UNIT

UNIT was an international military organisation which operated under the auspices of the United Nations, originally under the name of the United Nations Intelligence Taskforce (AUDIO: The Scream of Ghosts, PROSE: The Secret Lives of Monsters) until being renamed the Unified Intelligence Taskforce, (TV: The Sontaran Stratagem) alternately known as the United Intelligence Taskforce. (AUDIO: The Dalek Transaction) Its remit was to investigate and combat paranormal and extraterrestrial threats to the Earth, (TV: Spearhead from Space) to protect humanity, no matter what. (PROSE: UNIT History: Fighting the unknown) UNIT was not the only alien defence organisation, but it was certainly the one with which the Doctor had the closest personal involvement.

During his exile on Earth, the Third Doctor was even on the UNIT payroll, as scientific advisor. During this time, the Doctor maintained a lab, worked on the TARDIS, and was sent out to investigate unusual going-ons, usually elsewhere in England. The Doctor worked closely with Brigadier Alistair Gordon Lethbridge-Stewart, who left a mark on this organisation, even after he was gone. In the 21st century, UNIT was led by Kate Stewart, the Brigadier's daughter. Her reforms included a greater focus on science, over and above the military structures of the previous century. Additionally, the Doctor never officially resigned from their job at UNIT.

Due to the machinations of the Grand Serpent, UNIT's activities were wound down in 2017 (TV: Survivors of the Flux) and operations were suspended and pending review by New Year's Day 2019, with all UNIT operations put on hold, following financial disputes and subsequent funding withdrawal by the UK's major international partners. (TV: Resolution) Soon afterwards, the Doctor remarked that UNIT was simply "gone", along with Torchwood. (TV: Spyfall) Ace, a former companion to the Seventh Doctor, also knew that UNIT was gone, though official protests continued from Geneva. (PROSE: At Childhood's End) By 2022, UNIT had been reinstated. (TV: The Power of the Doctor)

Accounts differed on whether UNIT survived into the mid-21st century, (AUDIO: A Death in the Family, PROSE: The Left-Handed Hummingbird, The Baron Wastes) and even as late as the 22nd century, (TV: Under the Lake) or came to evolve into one or many successors starting in the 21st century. (PROSE: Alien Bodies, The Indestructible Man, Cold Fusion, COMIC: The Mark of Mandragora, Echoes of the Mogor!, AUDIO: Council of War)

Roots and predecessors
An early 20th century counterpart to UNIT was LONGBOW. This world security organisation was set up by the UN precursor, the League of Nations. LONGBOW dealt with the occasional extraterrestrial incident, but was disbanded after the League and it failed to prevent World War II. (PROSE: Just War)

The roots of UNIT itself, however, lay in later alien encounters. The Intrusion Counter-Measures Group headed by Group Captain Ian Gilmore, which got involved in the Shoreditch Incident, served as a specialised military force with scientific assistance would seem almost a trial run for UNIT, though not an international organisation. Though Gilmore did have two scientific advisors serving much as the Third Doctor and Liz Shaw would later, the Seventh Doctor did most of the work on the technical end. (TV: Remembrance of the Daleks, PROSE: Who Killed Kennedy) The ICMG were later succeeded by the Home-Army Fifth Operational Corps (PROSE: Birds of Passage) or a new version of the team. (AUDIO: Who Killed Toby Kinsella)

Formation
The United Nations were aware the world faced threats from extraterrestrial sources. As space programmes sent probes deeper and deeper into space, mankind was drawing attention to itself. (TV: Spearhead from Space) According to one account, the United Nations had been working on a taskforce for alien threats since at least 1958. General Farquhar was tasked with setting up UNIT's British end and asked for assistance from a friend of his, a man named Prentis, in setting it up. There was a thirty-year investment plan by 1967, though UNIT was embarrassed when they missed the Post Office Tower incident (TV: Survivors of the Flux)

According to some accounts, an incident which led directly to the creation of UNIT was the takeover of London by the Great Intelligence, with robot Yetis and a deadly cobweb-like fungus. Assisted by the Second Doctor, another group of British infantrymen, led by then-Colonel Alistair Gordon Lethbridge-Stewart, beat back the Yeti from the tunnels of the London Underground. (TV: The Web of Fear) In reaction to the so-called "London Event", the British government formed the Home-Army Fifth Operational Corps to combat alien threats, headed by Lethbridge-Stewart. Lethbridge-Stewart was part of the organisation until the formation of UNIT in 1969 (PROSE: Who Killed Kennedy) or 1971 (PROSE: The Last Duty, Scary Monsters)

According to some accounts, Lethbridge-Stewart, unable to get the British government to form a permanent special operations force for alien threats, went over their heads to the UN Security Council, who proved more receptive. (PROSE: Who Killed Kennedy, Fear of the Web) The UN established UNIT with the mandate to investigate, monitor and combat such threats. This contingent was organisationally known as Department C19 within the British government.

As a United Nations group, UNIT often served as security at peace conferences, (TV: The Mind of Evil, Day of the Daleks) and the British contingent had foreign soldiers such as Sergeant Zbrigniev. (TV: Battlefield)

UNIT often faced hostility to its operations when investigating research facilities and companies. A common tactic against them was an appeal to any contacts in the Westminster government. These forced Lethbridge-Stewart either to back down or go over the government's heads to Geneva. (TV: The Invasion, The Green Death, The Claws of Axos)

Alistair Gordon Lethbridge-Stewart
According to one account, General Farquhar brought Corporal Lethbridge-Stewart into the organisation following C-Day and he quickly gained a reputation. That year, Prentis murdered Farquhar; undetected, he would continue to appear as a shadowy political figure throughought UNIT's history. (TV: Survivors of the Flux) At the suggestion of Gilmore from the ICMG, (PROSE: The Scales of Injustice) Lethbridge-Stewart was promoted to brigadier and put in charge of UNIT's British contingent. He would later refer to the promotion happening "since the Yeti do". (TV: The Invasion)

One of UNIT's first missions was an intensive investigation of International Electromatics, which turned violent. UNIT agents were killed and UNIT launched a helicopter raid to liberate prisoners at an Electromatics' facility. With the help, again, of the Second Doctor, UNIT discovered the company was a front for a Cyberman invasion, and was able to defend against it. Initially they had only intervened thinking Tobias Vaughn was involved in strange criminal activity, with the Brigadier agreeing with Captain Turner that Geneva would think he was mad without proof of the Cybermen's existence. (TV: The Invasion)

Lethbridge-Stewart became convinced of the necessity of scientific advice in battling extraterrestrial threats. He recruited Liz Shaw from the University of Cambridge. Around that same time, the Third Doctor had been exiled to Earth by the Time Lords. He agreed to join UNIT as its scientific advisor just in time to help defeat the Nestene Consciousness' invasion of Earth using its Autons in an attack on the Auto Plastics factory. (TV: Spearhead from Space)

UNIT investigated the disappearance of a RAF fighter in Scotland. The Doctor helped them discover the Armidians were responsible and, after his attempt at brokering peace failed, he instructed UNIT on how to earth the Tharon stone they drew their power from. During the investigation, Lethbridge-Stewart was impressed by RAF lieutenant Mike Yates and invited him to join UNIT. (AUDIO: Vengeance of the Stones)

UNIT was sent to investigate interference with experiments at Wenley Moor nuclear research facility, much to the chagrin of its director Charles Lawrence and head of security Major Baker, whom only reluctantly cooperated with UNIT. The Doctor uncovered the source of the interference was a colony of Silurians draining the facility's power. After helping UNIT foil their more radical leader's attempts at unleashing a plague and destroying the Van Allen Belt, the Doctor tricked the Silurians to return to hibernation. Against the Doctor's wishes, as he hoped to revive the Silurians again peacefully, the Brigadier ordered Corporal Nutting to blow up the Silurian base beneath Wenley Moor, permanently sealing the base off. (TV: Doctor Who and the Silurians) While in some accounts the tribe were said to have been killed as stated by the Third Doctor, (TV: Doctor Who and the Silurians) the Eleventh Doctor, (TV: Cold Blood) and Madame Vastra, (AUDIO: Rescue) according to another account, the Third Doctor said they were only entombed. (PROSE: The Scales of Injustice) UNIT subsequently investigated ancient archeological sites in case of any Silurian links. (AUDIO: AWOL)

Weeks after the Silurian incident, UNIT responded to the crash of an alien spaceship, taking it to Vault 75-73/Whitehall for examination. The pilot transpired to be a Mim scout which took the Doctor's form and exploited it to disable Earth's nuclear defences ahead of an invasion. The real Doctor helped UNIT destroy the scout, with Sergeant Robin Marshall being killed in the effort. The vault was sealed with the remains of the Mim inside, for fear of it reforming. (AUDIO: Shadow of the Past)

UNIT was asked to provide security for the return of the Mars Probe 7. (AUDIO: AWOL) They discovered alien ambassadors had replaced the astronauts upon their return to Earth and had subsequently been kidnapped by General George Carrington who was planning to convince the world's authorities to wage war against them. With the Doctor's aid, UNIT thwarted his plans and arranged the safe exchange of ambassadors for astronauts. (TV: The Ambassadors of Death)

UNIT was compromised by soldiers conditioned by the Unzal. When activated the soldiers rounded up UNIT's personnel, seizing control of the Geneva headquarters. Via the Doctor's TARDIS control console, the Doctor, Liz and Lethbridge-Stewart escaped the takeover of UNIT-UK and fled on the stand-by Hercules jet. They deduced the source of the conditioning to the Fulcrum training and confronted the Unzal there, freeing their human ally Cherilyn Dankworth from their conditioning and exposing their invasion force so combined air forces could defeat them. (AUDIO: The Unzal Incursion)

Whilst providing security at the Inferno Project in Eastchester, UNIT encountered the Primords. (TV: Inferno)

After the Doctor and Liz uncovered a crashed Cyber-ship in Cambridge, the Brigadier ordered his men to destroy it despite the Doctor having managed to put the Cybermen aboard in stasis. (AUDIO: The Blue Tooth)

UNIT troops led by Sergeant Benton successfully fought off a fleet of Silurians on the Kent coast, while troops led by the Brigadier rescued the Doctor and Sergeant Mike Yates from a splinter group of C19 in Northumberland. After this, Liz Shaw left UNIT. (PROSE: The Scales of Injustice) She went on to help the Ministry of Defence found the P.R.o.B.e. in the 1990s (HOMEVID: The Zero Imperative, The Devil of Winterborne) and was again associated with UNIT by 2010. (TV: Death of the Doctor)

Jo Grant was recruited to be the Doctor's new assistant. (AUDIO: Taken for Granted) Not a scientist, Jo had only managed to take science up to A level, of which she later stated, "I never said I passed". As Jo began assisting the Doctor, UNIT met and made an enemy out of another Time Lord —. (TV: Terror of the Autons) After foiling several of his schemes, including using the Keller Machine, (TV: The Mind of Evil) bringing the parasitic lifeform Axos to Earth (TV: The Claws of Axos) and advising the Mega's invasion, (AUDIO: The Mega) UNIT finally caught and imprisoned the Master after his attempt to awaken Azal in Devil's End. (TV: The Dæmons)

The Soviet Union's version of UNIT was the Yedinitza, which secretly became a scientific advisor to during the 77 years he was trapped on Earth for. (PROSE: The Master and Margarita) With tensions rising between superpowers, UNIT was called upon to provide security at a crucial conference at Auderly House. The conference was disrupted by attacks from misguided guerilla fighters from an alternate future and the Daleks, however UNIT were able to evacuate the delegates whilst fending off the Daleks, preventing a diplomatic incident. This prevented the timeline which the guerillas and Daleks had come from existing. (TV: Day of the Daleks)

Whilst the Doctor was away on Peladon, UNIT were forced to turn to the captive Master for aid in stopping an incursion from a parallel universe. (PROSE: The Face of the Enemy)

After numerous escape attempts from UNIT's custody, (COMIC: The Man in the Ion Mask, PROSE: The Switching) the Master was transferred to the Fortress Island. He managed to arrange his escape by manipulating the prison's governor, George Trenchard, and awakening a nearby colony of Sea Devils. (TV: The Sea Devils) During Omega's attempt to escape the anti-matter universe, UNIT HQ was besieged by gell guards. Various personnel and UNIT HQ itself were transported to the anti-matter universe, but returned home by efforts of the Second and Third Doctors. (TV: The Three Doctors)

When the Doctor's exile was ended, (TV: The Three Doctors) his association with UNIT became more sporadic. However the Doctor admitted to frequently coming back to UNIT after having come to enjoy their company. After his exile was lifted, the Doctor helped them combat Ramón Salamander, (COMIC: The Heralds of Destruction) the Gaderene, who had allied with the Master, (PROSE: Last of the Gaderene) and investigate the new humans. (AUDIO: The Rise of the New Humans) At Jo's urging, UNIT investigated Global Chemicals and discovered they had unwittingly created giant maggots and were run by an insane computer, BOSS. After the Doctor helped shutdown BOSS, Jo decided to leave UNIT. (TV: The Green Death)

After Jo's departure, the Doctor became less involved with UNIT but still helped them investigate the disappearances of scientists (TV: The Time Warrior) and thwart Operation Golden Age, which UNIT Captain Mike Yates betrayed his colleagues to help. (TV: Invasion of the Dinosaurs) UNIT was briefly infiltrated by the Remoraxians, which was exposed by Liz Shaw who summoned the Doctor back to Earth to resolve the Brigadier's increasingly erratic behaviour. (COMIC: In With The Tide) The Doctor also made use of UNIT's resources whilst researching ESP. His research embroiled him in the machinations of the Eight Legs, which resulted in him sacrificing his life to stop. Fatally poisoned, the Doctor returned to UNIT HQ where he regenerated in front of the Brigadier and Sarah Jane Smith. (TV: Planet of the Spiders) After recovering from his regeneration, the Fourth Doctor helped UNIT investigate the Think Tank and deal with their K1 robot. He subsequently departed, with Sarah Jane and UNIT's medical officer Harry Sullivan. (TV: Robot)

The Fourth Doctor worked with UNIT on much fewer occasions. He was summoned back to Earth by the Brigadier using the Space-Time Telegraph to investigate a series of attacks on oil rigs, discovering the Zygons were responsible and averting their gambit in London. Afterwards Harry Sullivan chose to return to duty at UNIT, whilst the Doctor and Sarah set out for UNIT HQ by TARDIS. (Terror of the Zygons) After several detours on the way back to UNIT, (TV: Planet of Evil, Pyramids of Mars) the Doctor and Sarah arrived in time to stop the Kraal invasion of Earth alongside UNIT forces led by Colonel Faraday (the Brigadier having gone to Geneva). (TV: The Android Invasion) Whilst he and Sarah based themselves on Earth between trips, the Doctor still answered the Brigadier's summons on occasion. (PROSE: A New Life, Avast There!, Double Trouble)

The Doctor and Sarah attended UNIT's Christmas party, which was disrupted by a Voddod spaceship crashing. As soldiers mobilised the Doctor resolved the situation with the alien pilot Brac peacefully. (PROSE: UNIT Christmas Parties: Ships that Pass) UNIT recommended the Doctor to investigate the Krynoid pods that an expedition had discovered in Antarctica. Sir Colin Thackeray later called in UNIT to assist the Doctor and Sarah Jane after one of the pods fell into the hands of Harrison Chase, who led a Krynoid germinate. With Lethbridge-Stewart in Geneva, Major Beresford led the response, sending soldiers to Chase's mansion and ordering an air strike to destroy the Krynoid before it could spread its seeds. (TV: The Seeds of Doom) Afterwards the Doctor's association with UNIT appeared to come to an end, though he never officially left UNIT. (TV: The Sontaran Stratagem)

Warrant Officer Benton oversaw the transport of radioactive cargo by UNIT Land Rover through woods outside Bolton. (HOMEVID: Wartime)

Lethbridge-Stewart was sent on a mission to Canada to investigate sentient electricity pylons, whilst Faraday was in Switzerland. (AUDIO: The Oseidon Adventure) During this time, after discovering the Master attempting to open a wormhole for an alien invasion in Dark Peak, the Doctor had his companion Leela communicate a message to attract UNIT's attention. (AUDIO: Trail of the White Worm) With Lethbridge-Stewart and Faraday away, Captain Clarke led UNIT forces to Dark Peak and assisted the Doctor and Leela stop a second Kraal invasion. (AUDIO: The Oseidon Adventure)

Jasper Corrigan, the head of new private anti-alien organisation Albion Defence, attempted to discredit UNIT by using telepathically-generated monsters. Lethbridge-Stewart was aided by the Ninth Doctor and his companions Rose and Jack in tracking the source of Albion's monsters, while UNIT nurse Tara Mishra sacrificed her career by claiming that she worked for Albion Defence to publicly expose their crimes. Afterwards Tara stowed away aboard the Doctor's TARDIS. (COMIC: Official Secrets)

When Robert Bertram provided UNIT with new virtual reality training equipment, Lethbridge-Stewart and Benton were forced to covertly act against UNIT when they realised that the equipment was altering the minds of those who used it. During their investigations into Bertram, they were reunited with the Doctor in his seventh incarnation. Identifying Bertram as his foe Mortimus, the Doctor was able to thwart his scheme by destroying the equipment he was using to contain Artemis, a Chronovore he had managed to capture, but the Brigadier was killed during the struggle. Due to the role the Doctor's companion Ace had played in her rescue, Artemis granted Ace one favour, with Ace choosing to alter her history so that she was in a position to save the Brigadier from death. Afterwards the Doctor hypnotised the Brigadier to retire from UNIT and forget about this meeting. (PROSE: No Future)

Lethbridge-Stewart went to Geneva to finalise his retirement from UNIT, encountering the Fourth Doctor and Leela and the Molai at the Hotel des Rois. (AUDIO: The Revisionists)

After Lethbridge-Stewart
Lethbridge-Stewart retired in 1976 to teach mathematics at Brendon Public School. His successor was Colonel Charles Crichton. (TV: The Five Doctors) Benton and medical officer Harry Sullivan also left. (TV: Mawdryn Undead) A few years after the Doctor's departure, Elizabeth Klein became the scientific adviser of UNIT. (AUDIO: Dominion) She was once visited by the Seventh Doctor at a UNIT facility. (AUDIO: The Architects of History)

In 1980, UNIT soldiers took control of the crash site of Beep's spaceship in Blackcastle. Beep later put them under the influence of Black Sun radiation, though they were later released. (AUDIO: Doctor Who and the Star Beast) The same year, Captain Muriel Frost went to Pompeii after the Doctor's TARDIS was discovered among the ruins. UNIT contacted the Fifth Doctor about the discovery. (AUDIO: The Fires of Vulcan)

During Crichton's tenure as Colonel, he hosted an anniversary reunion of UNIT, which Lethbridge-Stewart and the Second Doctor attended, (TV: The Five Doctors) and worked with the Sixth Doctor on UNIT business in Derbyshire. (AUDIO: I Wish It Could Be Christmas Every Day)

In 1984, (AUDIO: Warlock's Cross) Colonel Lewis Price was in charge of UNIT. He led an investigation into an alien signal, encountering the Fifth Doctor who was following the same signal. The Doctor took a disliking to Price and convinced UNIT's medical officer, Daniel Hopkins, to help him investigate alone. They found the source was Annabel Morden's clinic where she was luring and vivisecting aliens, so Hopkins called in the UNIT troops to shut her clinic down. After discovering her reasons, namely her having a half-alien child, the Doctor decided to help Annabel escape with the alien father who and returned. Price had them pursued but ultimately agreed to help them go. (AUDIO: The Helliax Rift)

On 12 December 1985, UNIT Arctic base Skywatch-7 was attacked by a Zygon. (COMIC: Skywatch-7)

Circa 1986, Hopkins took a leave of absence from UNIT after his family died in a house fire. Shortly after he returned to duty, Operation Warlock's Cross took place in which 8 scientists, 2 test subjects, and 1 alien perished in a thermal explosion when UNIT investigated an alien spaceship. (AUDIO: Warlock's Cross) A year later, Hopkins encountered the Cybermen who were scouting Earth ahead of an invasion and agreed to help them infiltrate UNIT, believing conversion to be the answer to his grief. During this time UNIT began the Cerberus program, a network of satellites to watch for signs of alien attack. (AUDIO: Hour of the Cybermen)

In 1987, Prentis killed the retiring Millington with the aim of succeeding him as chair of the UNIT Oversight Committee. (TV: Survivors of the Flux)

Approximately five years after the Helliax incident, Colonel Price called the Sixth Doctor for help when the UK faced an inexplicable drought. As they investigated they found a group of alien refugees who had fled to Earth from the Cybermen. The Cybermen arrived to finish them off and captured Price. Price escaped captivity aboard their spaceship, only to discover it was beneath the Cerberus base, and was killed by Hopkins. The Doctor discovered the Cybermen had compromised the Cerberus satellites and were using them to drain the UK's water, planning to do the same to the entire Earth. He infiltrated a fleet of Cyber-Ships hidden underwater and managed to reprogram the satellites to attack fluid in Cyber technology and exposed the location of the fleet to UNIT. The Doctor delivered Hopkins, who was comatose after the early stages of his cyber-conversion were interrupted, into UNIT's custody. (AUDIO: Hour of the Cybermen)

1990s
Colonel Lafayette took over UNIT, with Elizabeth Klein serving under him. UNIT faced a series of alien invasions from other dimensions, with a previously unknown arriving to lend assistance. During the incursions Lafayette was killed by the Skyheads and replaced as head of UNIT by Major Wyland-Jones. The Seventh Doctor and Raine arrived on Earth and also began helping UNIT, though the Seventh Doctor clashed with his other self causing UNIT to become suspicious of both of them. Eventually the Seventh Doctor discovered the other Doctor was actually the Master, who had caused the dimensional crisis and manipulated it to his own ends, and foiled his plan, ending the incursions. (AUDIO: Dominion) For a time, Elizabeth and her assistant Will Arrowsmith travelled with the Doctor. (AUDIO: Persuasion, Starlight Robbery, Daleks Among Us)

By 1994, Daniel Hopkins had regained consciousness and was being held in a UNIT prison, the Spar, overseen by Colonel McKenna. Elizabeth Klein was present at the facility when the Seventh Doctor arrived. They were both caught up in Linda Maxwell's breakout of Hopkins on behalf of Ship, the spacecraft at Warlock's Cross which was planning to trick UNIT into attacking it so it could destroy itself, devastating Earth in the process. Elizabeth and the Doctor managed to prevent McKenna falling for Ship and Hopkins' manipulations. (AUDIO: Warlock's Cross)

In the 1990s, Iris Wildthyme worked part-time as UNIT's special scientific advisor. (PROSE: Interference - Book Two, Bullet Time)

In 1995, UNIT, led by Brigadier Crichton, combatted the manifestation of the Great Intelligence at New World University. (HOMEVID: Downtime)

In 1997, Brigadier Winifred Bambera was tasked with overseeing a nuclear weapon convoy. The convoy became stuck in Carbury where Bambera was forced to work with the Seventh Doctor and Ace against an invasion by Morgaine and her armoured knights from another dimension, calling Lethbridge-Stewart out of retirement to assist her. Major Husak's led a branch of Czechoslovakian UNIT troops in assistance (TV: Battlefield)the only European UNIT troops available as most were observing the Azanian ceasefire. (HOMEVID: Battlefield: Special Edition) In the same year, the Seventh Doctor and Sarah Jane Smith exposed the existence of the Cortez Project within UNIT (PROSE: Bullet Time) and UNIT's division in the United States, led by Brigadier-General Kramer, worked with the Eighth Doctor, Sam Jones, and Carolyn McConnell to eradicate a horde of vampires living in San Francisco. (PROSE: Vampire Science)

In the late 1990s, whilst Lethbridge-Stewart was at a summit in Geneva, (COMIC: Darkness, Falling) UNIT, led by Captain Muriel Frost, investigated Mandrake, a potent new street drug in Britain being sold by Stranks. The Seventh Doctor and Ace arrived on Earth and connected Mandrake to the Mandragora Helix. They assisted Frost in combatting it, during which Frost was promoted to Colonel. (COMIC: The Mark of Mandragora) Later, UNIT, Corporal Ives and Colonel Muriel Frost helped the Seventh Doctor and Ace investigate a potential UFO that caused the crash of a German pilot during World War 2. After Ives and Frost helped the Doctor to confirm that a UFO, or rather a Q'Dhite Mind-Treader, was involved, however Ace was kidnapped by Alex Evening, who had found the Mind-Treader some time prior to the Doctor's investigation, and had used the Mind-Treader to build a world of his own which he took Ace to. The Doctor, Ives, Frost, and a company of UNIT soliders went in the Doctor's TARDIS to this world, where they fought Alex and the beings he created, with UNIT sustaining large casualities. (COMIC: Evening's Empire)

UNIT and Torchwood looked into the destruction of space shuttle Titania in re-entry, finding no evidence of anything unusual. (AUDIO: Dark Side of the Moon)

In 1998, Bambera led the unsuccessful pursuit of arms dealer Roman Krojač in Valge Maja. She intended to resign from UNIT following this failure but was summoned to UNIT Central in Geneva and offered a promotion to commander of UNIT-UK. She declined and accepted a final mission to protect a shipment of secret Soviet era canisters from Krojač, discovering they contained Chuchuna once imprisoned by the Network. After re-containing the Chuchuna, who had killed Krojač after he'd released them to aid his escape from UNIT, Bambera reconsidered the offer and accepted the post leading UNIT-UK. (AUDIO: Rogue State) At the behest of the newly appointed scientific advisor, Dr Louise Rix, Bambera and Savarin investigated Caverhurst Seedbank and Research Facility following the disappearance of two scientists. Discovering Dr Winston Grange had developed caterpillars capable of deageing anything into non-existence, Bambera had them destroyed to stop them spreading whilst Rix devised a way to restore them to normal. (AUDIO: Time Flies)

UNIT oversaw security at the BSP's launch of space station Britannia, ensuring the launch went successfully despite the attempts of an entity claiming to be the spirit of deceased astronaut Helena McNamara to prevent it. (AUDIO: Dark Side of the Moon)

Bambera, Rix and Savarin investigated the Hoplite Frequency developed by Colonel Hagen, (AUDIO: The Frequency) and supernatural occurences at The Dunes Hotel. (AUDIO: Haunt) At one point the Eleventh Doctor helped the Brigadier, leaving his contact details with Rix in case they needed him again. (AUDIO: Prologue - Clara)

At the end of 1999, UNIT provided security at the United Nations Security Council summit at St James' Palace. The summit proved to be a front of allies of the Zeta Hydri, led by Dame Lydia Kingsley, to gather the world leaders whilst Zeta Hydri invaded, using the Hoplite Frequency. Bambera refused to surrender, managing to send word of the traitors to the outside, whilst Rix discovered the invaders' weakness to high frequency sounds from a captive scout held by MI6, which she and Savarin exploited by reaching the Palace and broadcasting it in the Frequency's place. The Zeta Hydri were forced to retreat whilst their human allies were caught fleeing the Palace. In the aftermath of the invasion, UNIT decided to relocate UNIT-UK's headquarters to the Tower of London. (AUDIO: The Last Line of Defence)

At some point in the late 20th or early 21st century, Sarah Jane Smith published the book UNIT Fighting for Humankind about the history of UNIT. (TV: Whatever Happened to Sarah Jane?)

General trends
In the name of "homeworld security", (TV: Enemy of the Bane) UNIT adopted a controversial attitude towards civil rights and civil liberties which the Tenth Doctor found disquieting. (TV: The Sontaran Stratagem) UNIT maintained a secret prison where detainees could be held without charges being pressed or without the usual rights of prisoners. Among those kept as a prisoner by UNIT was Toshiko Sato after she stole blueprints for a sonic disruptor from the Ministry of Defence, despite having done so under duress. She was only released when Jack Harkness recruited her to work for Torchwood Three, even then with the condition she'd work for Torchwood for five years. (TV: Fragments)

At sometime prior to the Sontaran invasion, UNIT changed its name from United Nations Intelligence Taskforce to Unified Intelligence Taskforce. UNIT retained its traditional logos, even though they displayed the now-technically incorrect initialisation "U.N.I.T." (TV: The Sontaran Stratagem) The UN had come to publicly deny any connection with UNIT, forcing the secretive military organisation to alter its name. (PROSE: The Secret Lives of Monsters)

Specific events
In 2000, Alistair briefly came out of retirement to do reconnaissance for UNIT in Lanyon Moor, where he met the Sixth Doctor and Evelyn Smythe. (AUDIO: The Spectre of Lanyon Moor)

In 2001, Brigadier Bambera worked with the Seventh Doctor, Ace and Raine to investigate threats to secret experiments UNIT was conducting at Margrave University, discovering a student, Scobie, was working with the Numlocks. (AUDIO: Animal)

In 2004, (PROSE: Rise of the Dominator) the UK division of UNIT faced being shut down and replaced with domestic group the Internal Counter-Intelligence Service (ICIS). When it became clear ICIS were brutal and dangerous, Lethbridge-Stewart and Colonel Emily Chaudhry deliberately revealed UNIT's remit to the press - stating UNIT had faced over two hundred invasions - and the existence of Silurian ambassadors. This was viewed as a hoax, but it forced the government to leave UNIT in charge of alien matters, leading to uneasy co-existence with ICIS. (AUDIO: The Coup)

Unknown to UNIT, their leader, Colonel Brimmicombe-Wood, was an ICIS plant who had been groomed to assume leadership of their rival. (AUDIO: The Wasting) After Brimmicombe-Wood disappeared whilst transporting an alien spacecraft, Colonel Robert Dalton was placed in temporary command of UNIT. He and Chaudry reluctantly began working together, preventing the meltdown of a nuclear submarine (AUDIO: Time Heals) and killing the Vârkolak in Southend. (AUDIO: Snake Head) ICIS attempted a coup but were foiled by UNIT, however Dalton was killed in the process. (AUDIO: The Longest Night) Aided by Lethbridge-Stewart, UNIT stopped a worldwide pandemic of an alien virus, during which they found Brimmicombe-Wood and discovered his true loyalties. With ICIS shut down, Colonel Chaudry was given command of the UK contingent and suggested Lethbridge-Stewart become her scientific advisor. (AUDIO: The Wasting)

After the attempted invasion of Earth by the Nestene Consciousness on 5 March 2005 (TV: Rose) or on 26 March 2005, several UNIT officers coordinated clean-up efforts shortly after: Staff Sergeant A. Frederick and Capt Panos Karpidas dealt with information-based clean-ups, both using misinformation other similar tactics, with Frederick focusing on the press and Karpidas on the public; Lt David Judd focused on preventing any footage captured being shared on the internet; and Sgt Catherine Petts and her personnel focused on physical clean-up to the damage caused by the "mannequins" and the Consciousness. Frederick tried to seed a false theory to the press, that the mannequins only appeared to move due to the mannequins being made from faulty plastic with bubbles inside, leading the air inside to expand in reaction to a gas explosion, (PROSE: Operation Mannequin) and she also filed an embargoed press briefing to 28 March, which evasively ignored the allegations of the attack being mounted by terrorists or robots, and completely denied that it was in any way evidence of alien life existing. (PROSE: UNIT's Position on The London Incident)

After the Slitheen craft crashed into Big Ben and into the River Thames on 6 March 2006 (TV: Aliens of London) or 28 June, a group of UNIT officers discussed what to do in a operations board on a private part of the UNIT website; Major Jenny Maguire believed that containment of the situation was pointless, especially as the government was being uncooperative, however Staff Sergeant Annie Frederick advised that they wait out the crash in case it was a hoax. Over the course of the day, Corporal J Frinkstein posted updates about the situation, informing them of the advancements found on the craft and the "space pig", (PROSE: Operation London) which were conducted by UNIT, in assistance from Torchwood Three's Toshiko Sato, standing in for Owen Harper, at the Albion Hospital. (TV: Aliens of London, Exit Wounds)

UNIT then sent a delegation, including the Ninth Doctor, to a gathering of experts to 10 Downing Street, (TV: Aliens of London) as requested by the government, (PROSE: Operation London) however all of the experts were electrocuted by the Slitheen family, though the Doctor survived. (TV: Aliens of London) By the end of the day, Frederick informed the other officers that "he" had arrived, and the UNIT officers had differing opinions on his presence. While the UNIT officers didn't know about the Slitheen at the time, (PROSE: Operation London, Number Ten) it would later become known to UNIT of their involvement, which was recalled by Sam Bishop when he confronted another group of Slitheen with Christina de Souza. (AUDIO: Death on the Mile)

In 2006, a group of at least three Groske were stranded on Earth. UNIT found and recruited them. (TV: Death of the Doctor)

In Christmas 2006, UNIT had a command centre in the Tower of London under the command of Major Blake. During the Sycorax Invasion, Prime Minister Harriet Jones was brought to the facility and took command of the response. UNIT made contact with the Sycorax and they brought Harriet and the Major aboard. Blake was killed by the Sycorax leader. (TV: The Christmas Invasion)

Following the fall of Torchwood One at the Battle of Canary Wharf, (TV: Doomsday) a UNIT Black Ops agent, Edward Strong, infiltrated the Antebellum ahead of a raid by the Dow Cohort, planning to exploit it to gain access to the facility. Toshiko Sato, who had been brought as a hostage by the Dow Cohort, deduced Strong's true loyalties and foiled his plan. (AUDIO: War Chest) UNIT maintained contact with Torchwood Three, with Torchwood Three's leader, Jack Harkness, once having Tosh work on a "list for UNIT". (TV: Greeks Bearing Gifts) When the Cardiff Space-Time Rift fractured resulting in time slips across the world, UNIT was one of several organisations that noticed the strange appearances that were occurring worldwide and asked if it had anything to do with Torchwood. (TV: End of Days)

Sarah Jane Smith remained in friendly contact with UNIT during the 2000s, leading to its involvement in cleaning up the Coldfire Construction buildings left behind by the Slitheen. (TV: Revenge of the Slitheen) That said, she preferred to keep them at arm's length and handle things herself wherever possible due to her dislike of military responses, though she would not hesitate to call them in if she felt an incursion was beyond her ability to handle. (TV: The Last Sontaran) Her status as one of the Doctor's companions during his time as their scientific advisor seemed to have given her some pull; Sarah Jane said mentioning her name would ensure good pay. (TV: The Man Who Never Was)

By 2008, UNIT operated an aircraft carrier airship, the Valiant, which was mainly designed by British Minister of Defence Harold Saxon, who was in fact. (TV: The Sound of Drums / Last of the Time Lords)

A UNIT mission report concerning the Royal Hope incident, which dated the event to March 2008, recorded that moon rocks were retrieved from the Royal Hope Hospital. (AUDIO: Recruits)

At the request of US President Winters, UNIT took charge of first contact with the Toclafane from Prime Minister Harold Saxon, though their own authority was almost immediately usurped by Winters in turn, who desired the US to take credit for official first contact rather than UNIT or the United Nations. The event was held on the Valiant, which the Master had secretly designed for this purpose. The Toclafane killed Winters live on television, shortly followed by the Master activating his paradox machine and unleashing the Toclafane upon Earth. (TV: The Sound of Drums) This invasion was later erased from history and in the new timeline UNIT command called the Valiant requesting information on what had just happened to the President. (TV: Last of the Time Lords) Sometime afterwards the Doctor suggested UNIT recruit his former companion Martha Jones. (TV: Reset) Taking her unique field experiences into account, UNIT accelerated Martha's medical studies to make her a fully qualified doctor. (TV: The Sontaran Stratagem)

UNIT were involved in the Helsinki War operation. (PROSE: Something in the Water)

UNIT were called into Cardiff to combat an alien that was rampaging through the city. They arrived in force, driving several large trucks into the city. (PROSE: Harm's Way)

Jack Harkness requested Martha Jones to assist a Torchwood investigation into a series of murders, which they traced to the Pharm. (TV: Reset) After the death and subsequent resurrection of Torchwood's medical officer Owen Harper, Martha remained with Torchwood until she was content he was fit for duty. (TV: Dead Man Walking, A Day in the Death)

A UNIT facility was raided by Greys belonging to the Church of the Outsiders, which prompted Torchwood Three to begin investigating them. (AUDIO: Believe)

UNIT, led by a brigadier, confronted a Tomvaris destructor ship that came to Cardiff in search of the heir to the Yalnix Empire, which was being incubated by Jack Harkness. (AUDIO: Expectant)

In 2009, UNIT Australia saw off an advance party of Ice Warriors. (COMIC: The Age of Ice)

Sir Alistair Lethbridge-Stewart still had some involvement with UNIT in the 2000s (TV: The Poison Sky) as their "special envoy", being assigned a mission in Peru. However, he had come to dislike the "buzzwords" and "directives" that had overridden "common sense" amongst UNIT's current leadership. (TV: Enemy of the Bane)

UNIT became suspicious of ATMOS after fifty-two simultaneous worldwide deaths occured in cars fitted with ATMOS technology. Under the direction of Colonel Mace, UNIT carried out Operation Blue Sky to seize the ATMOS factory and Martha was tasked with recruiting the Doctor's aid. Confronting ATMOS' inventor, Luke Rattigan, with Private Jenkins the Doctor discovered Sontarans were behind ATMOS. After narrowly escaping being assassinated via ATMOS in a UNIT jeep, he passed on word to Martha, unaware that she had been replaced with a clone by the Sontarans to compromise UNIT. (TV: The Sontaran Stratagem) The clone delayed raising the alarm until the Doctor returned to the factory himself, by which time the Sontarans were ready to begin their invasion and had activated the ATMOS devices to poison the atmosphere.

The Sontarans retook the factory to keep the original Martha hidden, as her clone was foiling UNIT's efforts to launch a nuclear strike against their spaceship in orbit. Due to the Sontarans' use of a Cordolaine field signal that disabled guns using copper-based ammunition, UNIT soldiers within the factory were unable to fight back and were completely routed, sustaining many casualties including Private Jenkins. Whilst the Doctor began his own scheme to foil the Sontarans, UNIT switched out their copper-based ammunition with bullets that utilised a rad-steel coating and, with air support in the form of the Valiant, staged a successful counterattack against the Sontarans in the factory. UNIT personnel watched on when the atmosphere ignited after the Doctor used Rattigan's prototype terraforming technology to clear ATMOS's fog. (TV: The Poison Sky)

Following the Doctor's defeat of the Sontarans, UNIT began reverse-engineering technology scavenged from the aliens, and launched Project Indigo to create a backpack-sized teleportation device. It was top secret, although Jack Harkness found out about it. Jones was seconded as medical advisor for the project and stationed at UNIT's base in New York City. (TV: The Stolen Earth) UNIT also developed a contingency plan called the Osterhagen Project; in the event of global conquest that seemed unending, any three out of five UNIT facilities would end humanity's suffering by destroying the planet with nuclear weaponry under Earth's crust. (TV: Journey's End)

Donna Noble notified UNIT of duplicates the Collectors had put in positions in power around the world and the position of the Collectors' ship. UNIT mobilised to capture the duplicates and trained their weapons on the ship forcing the Collector Prime to agree to handover the originals and withdraw. (AUDIO: The Chiswick Cuckoos)

Following the relocation of the Earth and 26 other planets to the Medusa Cascade, UNIT went on high alert, and then a war footing as the Dalek invasion began. Both the Valiant and the New York headquarters were overrun by Daleks and destroyed, and the United Nations surrendered soon after. Martha Jones escaped using the Project Indigo device, maintaining possession of an Osterhagen key in the process. (TV: The Stolen Earth) She reached the Osterhagen Station in Germany and found the Chinese and Liberian stations had been already activated. Despite her orders, she chose to make a final broadcast to the Daleks threatening to destroy Earth and was teleported away by the Daleks before the bombs could be triggered. The Doctor later asked her to have the Project dismantled. (TV: Journey's End)

During Easter, UNIT was called out to a tunnel near Brixton after a bus carrying the Tenth Doctor and other passengers had gone through a wormhole. The Doctor contacted the senior officer on site, Captain Erisa Magambo and also spoke with their scientific advisor Professor Malcolm Taylor. He managed to get the bus back to its original location, but it was followed by three members of the Swarm. Whilst Malcolm successfully closed the wormhole in the nick of time, Magambo and her soldiers dealt with the three stingrays by shooting them down with missile launchers. The Doctor recommended to Magambo that there might be two more potential UNIT recruits from the bus, namely Barclay and Nathan. (TV: Planet of the Dead)

Martha became increasingly dissatisfied with her work at UNIT. After a late night investigation of a shapeshifter on behalf of Torchwood Three with Gwen Cooper, they were forced to destroy the UNIT facility. As Martha had been the only member of staff present, Gwen suggested she use this opportunity to disappear. (AUDIO: Dissected) As a result, Martha went freelance, eventually joining up with Mickey Smith. (TV: The End of Time)

Captain Magambo had Martha summon the Doctor back to Earth to help UNIT investigate moving trees in Greenwich. He discovered they were Enochai and was tricked into unleashing them. As UNIT fought them, Magambo refused to heed the Doctor's advice and was convinced to follow the Advocate's plan to destroy the Enochai's buried spaceship. Her plan was avoided when the Doctor launched their ship into space instead, and he angrily admonished Magambo afterwards. (COMIC: Don't Step on the Grass)

UNIT and Torchwood made a joint effort to investigate the voices coming from the Mariana Trench. UNIT supplied Torchwood with a submarine, the Octopus Rock, and a ship to transport it, the USS Calvin. (AUDIO: Submission)

In September 2009, UNIT investigated when every child in the world stopped, which was a prelude to the return of the 456. Colonel Augustus Oduya met with civil servant John Frobisher and showed him locations of children who had stopped all over the world, announcing his suspicions of an alien invasion. He correctly deduced that if UNIT had pieced the situation together, then Torchwood Three also must have. (TV: Children of Earth: Day One) Arriving at Downing Street to witness the 456's first contact, Oduya wanted UNIT to be involved in the handling the incident. (TV: Children of Earth: Day Three) After Frobisher killed himself, Colonel Oduya was selected to continue negotiations with the 456, and UNIT soldiers entered Floor 13. Oduya asked — not as a representative but as a father — what the 456 would do to the children once they were handed over. Upon receiving the reply that the children would essentially be used for drugs, he was clearly horrified. Oduya was present when the the 456 Ambassador was killed due to the actions of Jack Harkness which saved the Earth. (TV: Children of Earth: Day Five)

UNIT was infiltrated by the Bane, who had come to Earth seeking Horath, at the same time a fugitive Bane, Mrs Wormwood, tricked Sarah Jane Smith into recovering the Scroll of Horath, the key to find him, for her instead. With the aid of Sir Alistair, Sarah Jane stole it from UNIT's Black Archive. Major Kilburne, in actuality a Bane, pursued her back to Bannerman Road. Lethbridge-Stewart shot him with a gun concealed in his cane. (TV: Enemy of the Bane)

When the Master turned every human into a copy of him on Christmas Day, UNIT came under his command. When the Tenth Doctor piloted the Hesperus to Joshua Naismith's mansion the following morning, the Master Race-controlled UNIT fired missiles at the Doctor. Wilfred Mott and Rossiter destroyed them. When Rassilon and the High Council arrived at the mansion, his first act was to reverse the Master race back to their human forms. (TV: The End of Time)

Early 2010s
On 4 May 2010, after the Eleventh Doctor had destroyed an awaking Cyberman army, he predicted that a lot of questions would be asked by UNIT. He advised Chisholm to simply mention his name. (GAME: Blood of the Cybermen)

In 2010, UNIT Australia led by Colonel McCay faced chrono waves in Sydney, which downed a plane and unleashed dinosaurs. The Tenth Doctor and Majenta arrived in Sydney and were recruited by UNIT into helping their investigation, with the Doctor discovering the Skith were responsible. Whilst the Doctor investigated, an exiled Skith leader infiltrated UNIT's underwater base, Underbase 1, with the aid of Fanson posing as UNIT corporal, and enslaved much of its personnel, using their resources to take the Doctor, McCay and Majenta to the Skith ship as prisoners. They managed to expose the Skith ship to the outside world, enabling Underbase 1 to destroy it with its main guns. (COMIC: The Age of Ice)

The same year, UNIT Japan, led by Major Hiraki, had Martha call in the Eleventh Doctor to help their investigation into Goruda. His presence exposed an Axon agent within UNIT, who tried to assassinate him, and led to Axos accelerating its plan by converting thousands of children who had drunk Goruda into Axons. UNIT defended the Doctor from frequent Axon attacks whilst he devised a plan to stop Axos, eventually succeeding by inciting rebellion amongst the converted children and reversing the polarity of the electron flow of Tokyo's power grid to drain power from Axos. (COMIC: The Golden Ones)

Later that year, rogue Colonel Tia Karim leagued with Claw Shansheeth to gain the Doctor's TARDIS. They created a ruse that the Eleventh Doctor had died and prepared his funeral in UNIT Base 5 so they could drain the life force of Sarah Jane Smith and Jo Grant through their memories of the Doctor. They attached them to the memory weave and began the process to conjure a TARDIS key. The machine was overloaded by the many memories of Jo and Sarah Jane and it self-destructed, killing the group. (TV: Death of the Doctor)

In 2011, after the Miracle Day phenomenon was negated, UNIT sealed off the Blessing. (TV: The Blood Line)

In August 2011, UNIT began detecting unusual disturbances around Hexford. (AUDIO: The Hexford Invasion) A version of the Second Doctor, in truth a clone created by the Skishtari, (AUDIO: Survivors in Space) approached them to help the investigation, requesting someone from the old guard so UNIT called Mike Yates out of retirement. The Doctor, Mike and two soldiers were dispatched to Hexford, basing themselves in Nest Cottage. After weeks of investigation a Skishtari ship arrived and with the aid of the Second Doctor abducted the entire village, despite the efforts of the Fourth Doctor to stop it. (AUDIO: The Hexford Invasion) Mike and the soldiers helped the villagers survive for three months on an alien moon, until the Fourth Doctor tracked them down and helped return Hexford to Earth. (AUDIO: Survivors in Space)

Leadership of Kate Stewart
In time, the Brigadier's daughter, Kate Stewart, became head of scientific research and, through great effort, was able to transform UNIT into a force run by science. With Kate taking on control of the entire organisation, UNIT took in Shakri cubes that had appeared across Earth and experimented on them; they subjected them to temperatures from -200 to 200 degrees Celsius, simulated a water depth of five miles, dropped one out of a helicopter at 10,000 feet and rolled UNIT's best tank on one. The cubes were left intact. A year later, when the cubes activated and behaved unusually, several dozen were contained and examined in the Tower of London. Stewart called in the Eleventh Doctor and Amy Pond on the Doctor's psychic paper to look into this. (TV: The Power of Three)

Under Kate's leadership, UNIT repelled another attempted invasion by the Nestene Consciousness, during which agent Josh Carter was converted into a Nestene agent, but eventually overcame his conditioning to rejoin UNIT, and Colonel Shindi was heavily injured by Autons. (AUDIO: Vanguard, Earthfall, Bridgehead, Armageddon) They also encountered the Tengobushi, who attacked the Tower of London (AUDIO: Power Cell, Death in Geneva, The Battle of the Tower, Ice Station Alpha) and the Silents, who manipulated an election to negate the Doctor's conditioning of humanity to attack them with the aid of mind controlled UNIT agent Josh Carter and attempted to start a war to wipe out humanity in revenge. (AUDIO: House of Silents, Square One, Silent Majority, In Memory Alone)

With the aid of veterans John Benton, Mike Yates and Jo Jones, UNIT combatted Jastrok's clan of Silurians. (AUDIO: Call to Arms, Tidal Wave, Retrieval, United) UNIT began investigating the Auctioneers after discovering their operations including Maria Gonsalves' attempt to sell technology taken from a Dalek, (AUDIO: The Dalek Transaction) and establishing a cloning facility from a captive Sontaran. UNIT collaborated with the Eighth Sontaran Battle Fleet to shut down the cloning facility. (AUDIO: The Sontaran Project)

On a raid of an Auctioneer base in Vienna, UNIT discovered a capsule capable of travelling to a parallel universe, with UNIT scientist Osgood and Josh Carter accidentally encountering parallel counterparts of themselves whilst experimenting on it. (AUDIO: False Negative) UNIT's experiments with captured Auctioneer technology on the Fortress Island accidentally enabled Cybermen from a parallel universe to invade N-Space. (AUDIO: Telepresence, Code Silver) During the fighting, arrived on the Island and was forced by Kate to help UNIT stop the Cybermen, (AUDIO: Master of Worlds) only for him to leave Wirrn egg behind as revenge. (AUDIO: Hosts of the Wirrn)

In 2013, after the minds intended for the Great Intelligence were downloaded back into their bodies, UNIT took control of the Shard in London. They saw the workers' "factory settings" from before the Intelligence took over restored, causing them to forget their work. (TV: The Bells of Saint John)

Later in 2013, after figures from the Under Gallery's stasis cube paintings had disappeared along with the glass of the paintings being smashed outwards, UNIT summoned the Eleventh Doctor under the instructions of Queen Elizabeth I from the 16th century. The figures in the paintings were actually Zygons who hid themselves inside in 1562 while waiting for the Earth to become more suitable for invasion. UNIT had accidentally airlifted the TARDIS to the National Gallery not knowing the Doctor was still inside. The Zygons later took on the biological forms of Kate and UNIT scientists McGillop and Osgood and tried taking over the Black Archive.

Trying to stop them, Kate set off the countdown for a nuclear warhead, which her duplicate was unable to cancel, but the Tenth, Eleventh and War Doctors broke into the Black Archive, erasing the minds of the Zygons and the real Kate, McGillop and Osgood and making them forget which was "real" and allowing both Kates to agree to cancel the detonation. The Doctors refused to return the memories of the two parties until they agreed to a peace treaty. (TV: The Day of the Doctor) Twenty million Zygons were resettled in human form among the humans worldwide as part of Operation Double, a covert operation outside of UNIT's normal strictures. (TV: The Zygon Invasion)

In 2014, all UNIT troops were occupied with spiked-headed robots that were emerging from the eruption at the El Hierro volcano. (PROSE: The Crawling Terror)

In 2014, prior to the month of August, UNIT assembled outside of the House of Commons to disintegrate a Kharitite that was feeding on the negative emotions inside the building and destroying it in the process. They threatened to disintegrate Alice Obiefune if she did not agree to step out of their line of fire, but the Eleventh Doctor arrived in time to stop them. When a walking squid exited the TARDIS, they initially believed the squid had either taken over the TARDIS or that the Doctor had regenerated into the creature. They planned to fire at it even if it was the Doctor. (COMIC: After Life)

In late 2014, UNIT helped the Twelfth Doctor and Clara Oswald defeat the Fractures. (COMIC: The Fractures)

Shortly afterwards, UNIT investigated 3W, (TV: Death in Heaven) an organisation set up by one Dr Skarosa to create a place to house the consciousness of the deceased. Meanwhile, the Twelfth Doctor and Clara discovered 3W while searching for the recently deceased Danny Pink, and learnt the organisation's true nature as an operation manipulated by, who used a Matrix data slice to create the Nethersphere where the minds of the recently deceased would be uploaded and converted into an army of Cybermen. When the Cybermen emerged from 3W's base in St Paul's Cathedral, (TV: Dark Water) UNIT soon arrived on the scene led by Kate Stewart. Capturing both the Doctor and the Master, UNIT brought the two Time Lords aboard their presidential aircraft, Boat One, where the Doctor was met by Colonel Ahmed and inaugurated as an emergency President of Earth.

At this time, clouds appeared over the world's major cities, raining cyber-pollen on the graveyards to convert the dead into Cybermen. These Cybermen, now possessing the ability to fly, attacked Boat One resulting in its destruction with all hands including Colonel Ahmed and Osgood with the Doctor and the Master escaping. Offered control of the Cybermen army by the Master, the Doctor refused to submit to her claim that he was like her, he handed it over to Danny Pink, who rallied all the Cybermen to self-destruct, taking the pollen clouds with them. However, one Cyberman remained, converted from the late Brigadier Lethbridge-Stewart. Having rescued his daughter from the destruction of Boat One, he returned to the graveyard where he saved the Doctor the obligation of killing the Master. Receiving his wish of a salute from the Doctor, the Brigadier flew off. (TV: Death in Heaven)

During the month when the Hyperions ruled Earth in the summer of 2015, UNIT became a small resistance group led by Kate Stewart. The Twelfth Doctor provided them with alien weaponry to fight back against the Hyperions in London. (COMIC: The Hyperion Empire)

Missy, having survived the Brigadier's blast, grabbed UNIT's attention by using a time stop to freeze every plane in the sky across the globe, so that she could discuss the Doctor's confession dial with Clara, with eight snipers sent to ensure Clara felt safe enough to talk to her. Later, UNIT's scientists used a computer algorithm to find anachronisms and "crisis points" revealing the location and time period of the Doctor's meditation on Earth prior to his demise. Missy then used her vortex manipulator to bring Clara to 1138 Essex. (TV: The Magician's Apprentice)

UNIT's forces in the UK, along with a platoon in Turmezistan, were all killed by a radicalised faction of Zygons called Truth or Consequences after the peace treaty between humans and Zygons began breaking down. (TV: The Zygon Invasion) The ceasefire was later put back in place. (TV: The Zygon Inversion)

Mayor Me considered her hidden trap street, which had existed in London for at least a century prior to Operation Double, to be a more favourable way of housing aliens on Earth as opposed to the settling of the Zygons amongst humanity. Later, in a desperate gambit to prevent Clara Oswald from sacrificing herself, the Twelfth Doctor threatened Me to relinquish the Quantum Shade on Clara or he would expose her trap street and bring UNIT and the Zygons down on it. (TV: Face the Raven)

In 2016, UNIT cleaned up the mess left by the Transhuman Sisters of the Unholy Protocol after they tried to kill. (AUDIO: And You Will Obey Me) In 2016, a UNIT team was brought in to take away Garry Fletcher's alien body-swapping technology. (PROSE: Joyride) In October 2016, Tanya Adeola attempted to hack the UNIT Mainframe to find any information about the events at Coal Hill Academy using a code she had found on Reddit. She was however unsuccessful. (TV: The Coach with the Dragon Tattoo)

Andrea Quill was aware of UNIT and asked Dorothea Ames if she was affiliated with them. Dorothea replied that who she represented were "far more modest than that." (TV: Brave-ish Heart)

Closure
The UK government decided to divert their funding due to Brexit, (PROSE: Lucy Wilson and the Bledoe Cadets) unaware that they were being manipulated by Prentis. Prentis claimed to have fought in UNIT's corner against its shutdown but, in 2017, told Kate that he was conceding defeat. She was aware that Prentis was alien and threatened to expose him and call in the Doctor, a threat which led to an assassination attempt and her going into hiding. (TV: Survivors of the Flux)

The order to "mothball" the entirety of UNIT came from Whitehall. The order came as a surprise to Ace, who was now the chief executive officer of A Charitable Earth. She had previously made sure the A Charitable Earth headquarters was built to overlook the Tower of London, thus allowing her to see the number of vehicles heading in and out. This would give her an early warning to unusual activity, but this warning system was now gone. (PROSE: At Childhood's End)

In early 2018, Lucy Wilson attempted to phone her grandfather's old allies to help with an alien threat, but nobody answered the number she had memorised. (PROSE: The Midnight People) On 1 January 2019, the Thirteenth Doctor attempted to contact Kate Stewart following an invasion attempt by the Daleks. However, this was unsuccessful, as she discovered that UNIT operations were suspended due to funding disputes. (TV: Resolution) By the end of the 2010s, the Doctor knew UNIT to be "gone", alongside Torchwood. (TV: Spyfall)

Rumours circulated of UNIT's closure in London by 2020. (AUDIO: Lost Property) Official protests for UNIT did continue from Geneva, but Ace recognised that the organisation was over, meaning the Earth was less defended. She speculated that UNIT may have survived if Brigadier Winifred Bambera had remained in charge, though, at least according to everything Ace had found, she was still missing in action after a Sea Devil attack. (PROSE: At Childhood's End) With Torchwood, UNIT, (TV: Spyfall) and other such organisations shut down, the Preternatural Research Bureau ended up being tasked with their former duties, although Director Giles could not figure out how his organisation survived the budget cuts. (PROSE: Preternatural Days)

UNIT Remnants
Despite the official shutdown, in August 2020 a group of UNIT operatives including Osgood and Stewart were involved with recording information on a Time Fracture in a former UNIT Black Site. (GAME: The Lonely Assassins) Sergeant Robert Dudley and Kate Stewart described themselves as former UNIT members during logs about the fracture. The Doctor sent a message about Operation Time Fracture that included a list of names of hundreds of individuals. Stewart broke every security protocol they had to show an individual the recordings, revealing she did so because their name was on the Doctor's list. She invited the individual to help save the universe. (WC: 14681 UNIT Field Log, 14682 UNIT Field Log, 14683 UNIT Field Log, 14684 UNIT Field Log)

During the 2021 Sontaran invasion of Earth of Flux Offensive during the cataclysmic event of the same name, Kate came out of the shadows to lead the human resistance against the Sontarans, becoming the personal nemesis to Prentis, (TV: The Vanquishers) whose shutdown of UNIT helped bring about the Sontaran occupation. (TV: Survivors of the Flux) With the help of the Thirteenth Doctor and Team TARDIS, Kate and her resistance triumphed, with the Sontarans destroyed by the Flux event and Prentis being exiled to an asteroid. (TV: The Vanquishers)

In 2022, Kate Stewart was leading what was left of UNIT. As memory of the Doctor disappeared, even affecting Kate, UNIT investigated a sudden spate of disappearances apparently connected to the Doctor who they knew nothing about. They interrogated the three hosts of The Blue Box Files, a podcast focusing on mysteries associated with the Doctor, as three people they'd been in contact with were among the missing. (AUDIO: Interrogation) Kate subsequently disappeared, leaving Osgood to takeover as Chief Scientific Officer. Osgood took the hosts to the Black Archive in the hopes they could shed light on UNIT's increasingly confused records however two of them, Cleo Proctor and Shawna Thompson, refused to cooperate after discovering UNIT had possessions of Cleo's missing father in storage. (AUDIO: Recruits)

UNIT studied the ghosts that began appearing around the world, though Abby became uncomfortable with their methods, whilst the population began disappearing at a rapid rate. (AUDIO: Requiem) Shortly afterwards Osgood disappeared. UNIT troops responded to the mass appearance of ghosts at the Powell Estate, with Abby taking the opportunity to reunite with her friends and abandon UNIT. (AUDIO: Rescue) After everyone but Cleo became ghosts, she and the Thirteenth Doctor made use of equipment UNIT had setup in the Powell Estate to start to make the ghosts nearby remember the Doctor and restore them, ending the memory crisis. (AUDIO: Salvation)

Reinstated
UNIT had been reinstated by late 2022, with a new logo, new uniform, and newly built headquarters in London. Kate hired Tegan Jovanka and Ace as freelance specialists to help her gather intelligence on alien threats.

UNIT called the Doctor for help against the Spy Master and briefly took him into custody, but their London headquarters was overrun by Ashad's Cyber-Warriors. Most UNIT soldiers were killed or converted before Kate and Tegan blew up the headquarters, leading Kate to complain that she had just signed the lease. Later, while attending a support group meeting of the Doctor's former companions, Kate joked that she might recruit them to UNIT. (TV: The Power of the Doctor) In the wake of the battle, a group that was allied with UNIT put out a wanted poster on the Cybermen, in part due to their assault on UNIT's headquarters. (PROSE: )

In 2023 UNIT called up Private Matthew Reeves during a date to respond to an alien spacecraft over Ealing. (AUDIO: Here Today)

Late 2020s
In 2027, UNIT was using WOTAN Base 1 to monitor all of the world's computers for information. (AUDIO: A Death in the Family)

In the late 2020s, Patrick Gormley used UNIT's files on Ace to confirm who she was. (AUDIO: Signs and Wonders)

2030s
In 2030, the Seventh Doctor, Ace and Bernice Summerfield visited UNIT HQ in Geneva and picked up a note from Cristián Alvarez which had been left for them in 1993. (PROSE: The Left-Handed Hummingbird)

Later 21st century
By 2040, UNIT was a shadow of its former self. (PROSE: The Baron Wastes)

Some accounts indicate UNIT was replaced further into the 21st century. By one account, it was replaced by the more militant UNISYC (United Nations Intelligence Security Yard Corps), (PROSE: Alien Bodies) which had its roots in the 1990s. (PROSE: Interference - Book One) By another account, it was superseded by the global military PRISM. (PROSE: The Indestructible Man)

Beyond the 21st century
UNIT still existed in 2119. Alice O'Donnell was a fan of their work, and was familiar with the Doctor's association with the group, and Mason Bennett wanted to work for them. (TV: Under the Lake) The Doctor still had ties with them, and the Twelfth Doctor assured Clara Oswald that they would cut out the Faraday cage from the Drum and take it into space as well as destroy the Arcateenian hearse to ensure that the Fisher King's writing wouldn't infect anyone else. (TV: Before the Flood)

Following human expansion into the galaxy, UNIT evolved into the Foreign Hazard Duty. (COMIC: The Mark of Mandragora, Echoes of the Mogor!)

By the 26th century, UNIT had become a secret society called the Unitatus. (PROSE: Cold Fusion) Unitatus survived at least until the 30th century. (PROSE: So Vile a Sin)

United Galactic Intelligence Taskforce (UGIT) was another of UNIT's successor organisations. (AUDIO: Council of War)

British branch
Whilst investigating International Electromatics, British UNIT had a command centre in the cargo hold of a C-130 Hercules military transport aircraft and could use the plane itself as a mobile base. (TV: The Invasion) The plane was kept on constant standby in case UNIT needed it. Whilst carrying Lethbridge-Stewart, Liz Shaw and the Third Doctor the Hercules was shot down by Unzal drones during their incursion. (AUDIO: The Unzal Incursion)

At the start of the Doctor's exile, the British branch of UNIT operated out of an office building in London, (TV: Spearhead from Space) near Whitehall. (AUDIO: Shadow of the Past) It also maintained a mobile headquarters in the form of a large bus-like vehicle that could be driven to the site of an incident. (TV: The Dæmons) The HQ subsequently moved a number of times, finally settling in a building in the country that had been built over the ruins of a priory. (TV: Pyramids of Mars) The Doctor would note that UNIT was more "homespun" during this era. (TV: The Sontaran Stratagem) Vault 75-73/Whitehall was maintained at the site of UNIT's original London headquarters. (AUDIO: Shadow of the Past)

In the 1980s, British UNIT established a facility for the Cerberus program of satellites. Unknown to UNIT, a Cyber-ship was secreted beneath it. (AUDIO: Hour of the Cybermen)

In the 1990s British UNIT maintained a prison facility, the Spar. (AUDIO: Warlock’s Cross) In the late 90s, UNIT's base was a small office building in Central London and had the ability to monitor emergency calls. It was located there in secret, pretending to be an office between a theatre and a language school. (AUDIO: Time Flies) The Warehouse facility contained relics from UNIT's missions. (HOMEVID: Auton)

By Lethbridge-Stewart’s era the British branch had a base in the Tower of London. (AUDIO: UNIT Dating) Following UNIT's security being compromised in 1999 it was decided to relocate the main headquarters there. (AUDIO: The Last Line of Defence) In this capacity the base was also known by the name Tower Ops. (PROSE: Guinevere One) By 2011 the Tower housed the Black Archive, (PROSE: For the Girl Who Has Everything) which had previously been located in a separate facility in the 2000s, (TV: Enemy of the Bane) along with the Grey Archive, Red Archive and Blue Archive. (PROSE: For the Girl Who Has Everything) In addition, British UNIT was known to have at least one detention facility by the 2000s, (TV: Fragments) a victim-retrieval station in Hereford which was destroyed in 2009, (AUDIO: Dissected) and a base beneath Mount Snowdon. (TV: Death of the Doctor)

In 2022, UNIT was briefly based in a office tower in London until Kate Stewart and Tegan Jovanka deliberately destroyed it after an invasion of Cybermen. UNIT had not finished paying the lease by this point. (TV: The Power of the Doctor)

Whilst not an official part of UNIT, King Henry's University had close ties to the organisation. (AUDIO: Power Cell) Margrave University also hosted secret experiments on UNIT's behalf. (AUDIO: Animal)

Branches outside of the United Kingdom
UNIT was an international organisation that pulled its members from every nation it maintained a presence within. As such, various military officials from throughout Earth's history had links to UNIT. (PROSE: The Secret Lives of Monsters) UNIT Central Control was in Geneva, Switzerland. (TV: Spearhead from Space, et al.) Martha Jones was briefly attached to Geneva when UNIT was tasked with handling security for the CERN project (AUDIO: Lost Souls)

The French division of UNIT was known as NUIT (or Nations Unies Intelligence Taskforce). (PROSE: The Dying Days)

The Russian division was named ОГРОН or OGRON. This stood for Operativnaya Gruppa Rasvedkoy Obyedinyonnih Natsiy, which roughly translated as United Nations Reconnaissance Operations Group. (PROSE: Emotional Chemistry)

South-East Asia possessed a multi-national UNIT contingent, UNIT-SEA, headquartered in Singapore. (PROSE: Bullet Time)

UNIT had a Japanese division by 2010. (COMIC: The Golden Ones)

Kriegeskind Castle in West Germany was converted into a UNIT base when the organisation was formed, serving as both a research centre and military outpost. It was destroyed following a paranormal outbreak. (AUDIO: Old Soldiers)

UNIT had Osterhagen Stations in Germany, Argentina, Liberia and China. (TV: Journey's End)

By the time of the Vietnam War, UNIT-US was fully operating in America, (PROSE: Bullet Time) and by the 1990s, there were multiple divisions, such as UNIT ONE and THREE, (PROSE: The Dying Days) however, in mid-2005, Major A Highway reorganised UNIT's many disjointed operations in America into a "pivotal single site operation", (PROSE: UNIT's New York Operation Expansion) that being the UNIT New York City Base. The centralised base now carried out projects such as Project Indigo in the 2000s with Martha Jones as Medical Director. The base was later heavily damaged by the Daleks. (TV: The Stolen Earth) Petronella Osgood later referred to Dr Jones working for UNIT North America. (AUDIO: The Dalek Transaction)

In the 1990s, Czechoslovakia possessed a specialist engineering group. (TV: Battlefield)

Australia's Underbase was an underwater UNIT base in the Sydney harbour; it contained a museum of alien relics. In 2010 it came under attack by the Skith. (COMIC: The Age of Ice)

UNIT had a base in the Arctic, which was attacked by a Zygon in 1985. (COMIC: Skywatch-7)

UNIT had a facility at Gibraltar. (AUDIO: The Turn of the Tides)

Mobile bases
From around 2008 on, UNIT possessed at least two flying carrier ships, the Valiant (TV: The Sound of Drums) and the Starling, (COMIC: The Age of Ice) which could be used as bases. The Valiant was destroyed after the Daleks relocated Earth, (TV: The Stolen Earth) but was rebuilt or replaced by a ship of the same name by the time of the 3W incident. (TV: Death in Heaven)

Whilst the Doctor held the title of President of Earth during the 3W incident and the breakdown of Operation Double, UNIT transported him onboard two specialised planes. The first was brought down by Cybermen and the second was shot down by Bonnie. (TV: Death in Heaven, The Zygon Invasion)

Rivals
One division within the Central Intelligence Agency headed by a man known only as Control was a rival of sorts to UNIT. (PROSE: The Devil Goblins from Neptune) A few years later, another American, Bill Filer, worked on friendly terms with UNIT. (TV: The Claws of Axos)

In Britain, UNIT would come into conflict with a domestic anti-alien agency named ICIS (Internal Counter-Intelligence Service), who had a nationalist agenda. (AUDIO: The Wasting) While not running into conflict with them, they were viewed with contempt by both the Forge, (AUDIO: Project: Twilight) and MI6. Under Director Woodrow, MI6 became aware of an alien incursion in London, but deliberately did not mention it to UNIT and tried to handle the situation themselves; this led to the agency being massacred by Cybermen and an unprepared Earth being assaulted. (COMIC: The Flood)

An internal conspiracy within UNIT, the Cortez Project, attempted to massacre any alien, hostile or not, that arrived on Earth. Its existence was exposed in 1997, and UNIT began hunting down its cells. (PROSE: Bullet Time)

Organisation
UNIT's status was supported by enabling legislation that allowed it to assume emergency powers when necessary. Although it operated under the authority of the United Nations, its members were seconded from the host country's military and were still bound to obey that chain of command. Lethbridge-Stewart, for example, reported to the Ministry of Defence and the Prime Minister. (TV: Terror of the Zygons) However, when such orders conflicted, appeals could be made to Geneva. The Enabling Acts helped establishing jurisdictional guidelines: article 17 of the Third Enabling Act set up Geneva's role, while article 18 was "Matters of Domestic Concern" and stated in such cases, UNIT "will place itself at the disposal of the host nation in all respects". (TV: The Time Monster, The Green Death)

In the United Kingdom, its secrecy was guaranteed by the Official Secrets Act. (TV: The Time Monster onwards) Some believed it to be a kind of covert counter-terrorist unit. (AUDIO: Degrees of Truth)

Despite the change of name to the Unified Intelligence Taskforce, the United Nations commanded and funded UNIT. (TV: The Sontaran Stratagem / The Poison Sky, Children of Earth: Day One)

Equipment
Its personnel had a wide range of weaponry to call on, some custom-made to combat specific threats.

The standard issue firearm in the 1970s was the L1A1 SLR, a British version of the FN FAL, which was the current rifle used by the British Army. In the late 1990s, UNIT troops were armed with the Steyr AUG assault rifles. (TV: Battlefield) As the Brigadier explained to the Doctor, these could be loaded with armour-piercing munitions for use against robots, explosive rounds for Yetis or gold-tipped rounds for use against Cybermen, as well as silver-tipped rounds kept in inventory "just in case". (TV: Battlefield) UNIT had a laser rifle at its disposal to deal with a Krynoid, though the weapon did not manage to kill it. (TV: The Seeds of Doom)

By the early 21st century the standard weaponry of UNIT consisted of G36 and G36C assault rifles, M4A1 assault rifles and limited numbers of K23B-styled M4s. (TV: The Poison Sky) They also had access to SIG-Sauer P226 pistols, as well as heavy weapons such as the FIM-92A Stinger and the AT4 rocket launcher.

UNIT had access to the USS Calvin, a ship and Octopus Rock, an advanced deep-sea submarine. They also had experimental diving suits made of dwarf star alloy capable of surviving miles below the surface. (AUDIO: Submission)

20th century
Early in its history, UNIT troops and officers wore beige uniforms consisting of a Velcro-fastening jacket with a green/grey shirt and silver/green tie; and beige berets not unlike the British Special Air Service. (TV: The Invasion through TV: Doctor Who and the Silurians) Apart from Brigadier Lethbridge-Stewart, who retained his regular uniform, the exceptions to this were new futuristic-looking uniforms, which consisted of a zip-up jacket without lapels worn over a rolled-neck sweater; (TV: The Ambassadors of Death) and combat gear, as worn by the troops stationed at the Inferno Project in Eastchester. (TV: Inferno)

They reverted to uniforms not unlike that worn by the British Army, but with the addition of UNIT logos and cap badges. (TV: Terror of the Autons through The Seeds of Doom)

In the 1990s, British and Czechoslovakian UNIT soldiers wore the standard uniforms of their host countries with the addition of a blue beret, with blue representing the United Nations. (TV: Battlefield)

21st century
By 2006, UNIT troops had adopted a paramilitary all-black look, with scarlet berets. (TV: The Christmas Invasion) Officers wore service dress (such as British Army No. 2 Dress or US Army Class A). (TV: Fragments, The Sontaran Stratagem, The Stolen Earth) As an alternative, officers could wear a black version of service dress with the UNIT beret. (TV: Turn Left)

By the time of Kate Stewart's leadership, troops wore black body armour with black helmets and tinted goggles. (TV: The Power of Three) Officers such as Colonel Ahmed wore a navy blue jacket with a white shirt and tie. (TV: Death in Heaven) When revived in 2022, troops wore black uniforms with dark blue/black body armour that had UNIT's name on the back. Troops on operations wore black helmets with the UNIT insignia enscribed, while troops in headquarters wore large black berets with white insignia. Non-combat staff in HQ wore normal office clothes in dark colours. (TV: The Power of the Doctor)

Divisions
UNIT maintained a number of specialised departments. One, the Paranormal Division, in which Lieutenant Hamlet Macbeth investigated psychic powers and phenomena. (PROSE: The Left-Handed Hummingbird) Broadsword was UNIT's intelligence wing and Special Ops division. (PROSE: No Future) It also maintained the Warehouse, a place to store alien artefacts; security breaches at this and similar facilities were handled by the Containment Team. (HOMEVID: Auton) Internal affairs were handled by the Internal Security Division. (HOMEVID: Auton 2: Sentinel) UNIT also maintained a warehouse known as the Black Archive. (TV: Enemy of the Bane)

In the late 1990s, UNIT's American branch had at least two divisions: UNIT ONE, the Creative Intelligence division; and UNIT THREE. (PROSE: The Dying Days)

Call signs
UNIT used a variety of call signs and code words for their agents. The most common call sign was Greyhound. By convention the senior officer (usually Brigadier Lethbridge-Stewart) was Greyhound One (TV: Invasion of the Dinosaurs) or Greyhound Leader. Other Greyhounds included Mike Yates as Greyhound Two, (TV: The Dæmons) Martha Jones as Greyhound Six, and Ross Jenkins as Greyhound Forty. (TV: The Sontaran Stratagem) The commander of operations was often called Trap One, with both Lethbridge-Stewart (TV: Invasion of the Dinosaurs) and Colonel Mace (TV: The Sontaran Stratagem) using the call sign at times. An alternative term was Watchtower. (TV: Doctor Who and the Silurians)

More unusual were the call signs used during the first World Peace Conference, which were based on planets of the Sol system, with the Brigadier as Jupiter and Mike Yates as Venus. (TV: The Mind of Evil) Lieutenant Richards, commanding a missile convoy, was designated Salamander Six-Zero. Brigadier Bambera, in the same operation, was Seabird. (TV: Battlefield)

Helicopter call signs included Windmill 347, (TV: The Mind of Evil) Eagle (TV: The Green Death) and "Uniform November Nine-Zero", (TV: Battlefield) whilst the Valiant was Hawk Major. (TV: The Poison Sky) UNIT's call sign for the TARDIS was Blue Eagle. (TV: The Day of the Doctor)

Alternate timeline versions
In an unstable mini-universe created by the Monk, (PROSE: No Future) the Wenley Moor incident resulted in the Silurians conquering Earth, with the remnants of UNIT led by Lethbridge-Stewart fighting a vicious insurgency against them. (PROSE: Blood Heat)

A deliberately altered timeline saw UNIT fighting a counter-insurgency against a British anarchist terrorist group named Black Star. A plain-clothes division named Broadsword had been created. (PROSE: No Future)

During the Year That Never Was, 's agents used technology previously belonging to UNIT, among other secret organisations. (AUDIO: Deceived)

UNIT in parallel worlds
The fascist Britain in a parallel universe the Third Doctor visited had its own version of UNIT, the Republican Security Forces, led by a counterpart of Lethbridge-Stewart. (TV: Inferno)

The Seventh Doctor visited one parallel universe in which humans had made peace with the Silurians after the Wenley Moor affair. In this universe, United Races Intelligence Command or URIC had replaced UNIT. An alternative version of Muriel Frost headed the organisation, following the death of the Brigadier in a bomb attack; this world's Doctor was killed in the same attack. (COMIC: Final Genesis)

In the Unbound Universe, Alistair Lethbridge-Stewart became the Brigadier of UNIT but had to face alien attacks without the Doctor's assistance. These included the “Plastic Purges”, lizards (which required the sacrifice of Mike Yates via time travel to stop) and the Ambassadors, who left a string of crators along North America. The Brigadier took drastic actions against these attacks, including bombing Surrey. (AUDIO: Sympathy for the Devil) In 1972, UNIT encountered the Daleks. Three Daleks were able to kill 47 men. (AUDIO: Masters of War) Due to UNIT's many disastrous failures, Alistair was regarded as a dangerous crackpot and ultimately driven out from UNIT. In 1997, he and the Doctor encountered UNIT forces in Hong Kong led by Colonel Brimmicombe-Wood. (AUDIO: Sympathy for the Devil)

In one parallel universe, a version of the Doctor was associated with UNIT, exploiting his credentials with the organisation to gain the confidence of Professor Eric Vollmer. (AUDIO: Full Fathom Five)

In Donna's World, UNIT soldiers retrieved the dead body of the Tenth Doctor following the Christmas Star incident, and later a division of UNIT worked with Rose Tyler to reverse-engineer the TARDIS and allow Donna Noble to go back in time and make her younger self turn left instead of right at a junction. (TV: Turn Left)

In Pete's World, President Harriet Jones created UNIT by merging Torchwood and the Preachers. UNIT was headquartered in Big Ben and the Meta-Crisis clone of the Tenth Doctor served as its scientific advisor. (AUDIO: The Siege of Big Ben)

Copyright
UNIT was created by Derrick Sherwin for the serial The Invasion, which served as a pilot for the Earth-bound years of the Doctor's exile. However, uncharacteristically, the rights for UNIT at least partially stayed with the BBC rather than belonging fully to the writer because at the time Sherwin worked as a BBC staff-member. This prevented him from independently developing a science-fiction series starring UNIT at the end of the 1980s.

Name controversy
It was because of the Doctor Who tie-in website U.N.I.T. using the original UNIT acronym (United Nations Intelligence Taskforce), the real world United Nations took legal action against the BBC and the acronym was hastily changed to the Unified Intelligence Taskforce.

The Making of Doctor Who

 * According to the non-narrative source The Making of Doctor Who, UNIT was overseen by a Commander-in-Chief in Geneva in the early 1970s.

Other matters

 * In 1984, a comedic stage play titled Recall UNIT: The Great Tea-Bag Mystery was produced, written by Richard Franklin (Captain Mike Yates) who also reprised his character in the play. The cast included Nicholas Courtney as the Brigadier and John Levene as Sergeant Benton and was performed between 20 August and 24 August as part of the.
 * The UNIT vehicles and the mobile headquarters used in many of the adventures from 1969-1975 were BBC Outside Broadcasting vans used by the BBC production unit, with the BBC logos on the vehicles covered up.
 * Several non-individualised UNIT ranks, such as commander, medic and soldier, are used in the Doctor Who: Legacy mobile game both as allies and as enemies.