The Invasion (TV story)

The Invasion was the third story of season 6 of Doctor Who. It featured the Cybermen in what became their established form until Earthshock in 1982.

The Invasion also featured the second appearance of Alistair Gordon Lethbridge-Stewart, now promoted to the rank which became his best known title - Brigadier. It additionally introduced the organisation known as UNIT, as well as the character of Corporal (later Sergeant) John Benton. Behind the scenes, it was the start of Terrance Dicks' record-setting tenure as script editor. Furthermore, it was the final major appearance of the Cybermen until Revenge of the Cybermen in 1975.

Synopsis
The Doctor, Jamie and Zoe return to Earth and become embroiled in the schemes of Tobias Vaughn. They meet up with an old friend, Colonel (now Brigadier) Lethbridge-Stewart, and some old enemies, the Cybermen.

Episode one
Jamie, Victoria and the Doctor have been all brought back to the TARDIS after their adventures in the Land of Fiction. They find that they are hovering over the dark side of the moon. As they look at the scanners they see something approaching them, they soon realise it is missile. The Doctor tries to move but the landing circuit is jammed. The Doctor wrestles with the controls. The missile explodes.

The TARDIS lands with a thud in a field of cows.

Inside the TARDIS, Zoe wonders why they were fired at without any questions being asked. The Doctor wonders if they have encountered whoever fired at them already. They check the scanner and the sight of cows tells them they are on Earth; the Doctor reckons in the Summertime of the 20th century. The TARDIS judders and the Doctor believes he needs some new parts. He decides to seek out his old friend Professor Travers for help. He takes one of the circuits from the console which causes the lights to fade. They make their way to the exit.

Once outside a lorry draws up. The driver asks if they are "getting out". The Doctor states that they are heading to London. The driver orders them in. The driver looks round nervously as they get in the cab. As he drives off they are being pursued by two motorbikes. The driver pulls off the road and disappears behind some trees. He stops the lorry and gets out, looking anxiously down the lane before walking off. The Doctor, Jamie and Zoe follow the driver into the undergrowth. The driver suspects that the company is on their trail. When the Doctor queries what he means by the company he is met with consternation, the Doctor states that they are strangers The driver wonders how they got into the compound. He explains that the company is International Electromatics, the largest electronics company in the world who have a vast monopoly on the electronics business and huge complexes forming large swathes of land. The driver reckons it's safe to get on the road again.

The lorry approaches a checkpoint. Jamie, Zoe and the Doctor are hidden away in the cab of the lorry. The driver presents his papers and is waved through. Soon after the driver stops his lorry and the travellers get out of the back. The driver tells them to get lost before driving off. The Doctor, Jamie and Zoe clamber over a hedge into a field. As they do the motorbikes pass them by. The guards pull up behind the lorry. As they dismount, one guard opens the lorry to search it. He discovers only milk. The main guard sees the driver's papers whilst the other guard continues his search. The main guard says he wants to take the driver in for questioning. The other guard finds nothing and nods to his partner. The driver states he is not going back to the compound. The guard pulls out his gun. The driver turns to get into the lorry but the guard shoots him.

The Doctor, Jamie and Zoe are hitch-hiking. A car stops and the Doctor says they want to go to London. The man nods and the Doctor, Jamie and Zoe get into the car.

Once in London the Doctor and his friends look up Travers' address but their is the name 'Watkins' on his doorbell and there is no answer. They continue raining into a young model by the name of Isabelle answers the door. She explains that Travers is in America with Anne and that her father, a Professor Watkins, is staying in his house. He is working for International Electromatics and has been away for weeks. The Doctor, seeing his only chance to fix his TARDIS, tries to contact Watkins but comes up against an automated answering service that tells him that Watkins is not available. They decide to go there themselves. Zoe decides to stay as she is enjoying modelling for Isabelle.

Two men in a car watch the Doctor and Jamie enter the IE building. They are met by a computer secretary. They, again, ask for Watkins and are, again, told he is not available. They want to speak to someone in authority - but they need an appointment. They need to see someone now - but they're all engaged. It's an emergency - but what kind of emergency? It's a private matter - an emergency cannot be a private matter. The Doctor switches the computer off in frustration. The Doctor and Jamie set off to find another way in.

One of the men in the car takes a photo of the Doctor and Jamie as they explore outside.

A further two men watch them in a video link. One of them flips a switch.

Two glass panels drop down either side of the alleyway that the Doctor and Jamie are in. Gas starts to seep in.

HQ deploy the two men in the car to get the Doctor and Jamie.

The gas has cleared and the guards open the glass panel. As the man prods Jamie with his foot, Jamie grabs it and trips him. The man pulls a gun. A man named Vaughan stops him. He appears to be called Packer. Vaughan orders the men to be brought to his office.

Packer is dismissed by Vaughan as soon as he gets to the office. Jamie is initially very aggressive but the Doctor is passive and apologises for the trespass. Vaughan introduces himself as the director of International Electromatics and states that their friend, Watkins, is very busy and is not available by choice. Jamie is satisfied and begins to ask Vaughan about circuits for the TARDIS. The Doctor kicks him. Vaughan's curiosity is peaked and asks how he can help. The Doctor reluctantly hands the circuits over to Vaughan. Vaughan is intrigued and says he'll send them to his workshop. As an apology to Jamie for Packer's rough treatment, he gifts him a disposable transistor radio before dismissing the Doctor and Jamie. Vaughan walks to the desk and flicks a switch. He asks Packer to show the Doctor and Jamie off the premises.

Packer escorts them out. The Doctor believes that Vaughan is not what he seems. He is not blinking at the rate that a normal human should. The Doctor considers him odd, sinister and inhuman.

In his office, Vaughan flicks a switch. A wall tilts back to reveal a piece of complex, alien equipment.

Episode two
As the Doctor and Jamie return from the IE building, they soon discover they are being followed. They start to run.

Back at Travers' house Zoe is modelling for Isabelle. She soon becomes distracted and worried about her friends.

The Doctor and Jamie are chased into an alley where they are caught by a pincer movement and loaded into the cars.

Vaughan shows the circuit given to him by the Doctor to his Assistant Researcher, Gregory. He is bamboozled by the technology. Vaughan gives him an hour to figure it out. He asks Packer for photos of the Doctor and Jamie.

Zoe has now become so worried about the Doctor and Jamie that her and Isabelle set off to find them.

On a mysterious runway the car the Doctor and Jamie were forced into boards a plane. They soon find themselves in the hub of a military base where they meet their old friend Colonel Lethbridge-Stewart, now promoted to Brigadier. It has been four years since they last encountered each other in the London Underground and the Brigadier is now in charge of the United Nations Intelligence Taskforce or UNIT, an international investigatory force. He tells the Doctor that he and Jamie have been being monitored since they left the complex and that he decided to pick the, up after they left the IE building. The Brigadier explains that people sometimes enter the IE building, yet never leave.

Zoe and Isabelle enter the IE building seeking the Doctor and Jamie. They try the computer in reception and enquire after them.

Upstairs, Vaughan unveils the alien machinery and asks for information regarding the Doctor. The machine tells him that they are known and hostile. They were encountered on Planet Fourteen and must be destroyed before the invasion. An alarm interrupts this conversation. Zoe and Isabelle are displayed on Vaughan's screens.

The computer receptionist is giving no information to Zoe. Refusing to be beaten, she bamboozles the computer using ALGOL, complex mathematical equations. The machine starts to smoke and eventually explodes.

All this is watched by Vaughan. He calls Packer to bring the two girls up.

Isabelle and Zoe start to leave when they are intercepted by Vaughan's guards.

The Brigadier explains to the Doctor that many senior anti-IE figures have entered the IE building and returned completely for their company. Sifting through the photographs Jamie discovers a photo of the driver that helped them out of the IE complex. The Brigadier explains he was an agent and hasn't been heard of for twelve hours. The Brigadier explains that IE was practically unheard of until they started controlling computer lines and investing in micromonolithic circuits, then Watkins disappeared and UNIT got involved. The evidence is not substantial enough for UNIT to search the IE building so the Doctor and Jamie are on their own, however the Doctor is given a transceiver if ever he needs to contact UNIT. The Doctor and Jamie are returned to London.

On their return to London they discover Travers' house empty. They enter and the Doctor absentmindedly dismantles the radio that Jamie was given by Vaughan have him. He discovers micromonolithic circuits that have no place to be in a radio. They find a note that Isabelle and Zoe have gone to the IE building. Panicked they follow them.

Vaughan berates Zoe and Isabelle for the destruction of his computer. Vaughan explains that Watkins has started to be uncooperative and that Isabelle could be useful in persuading him to work. Zoe and Isabelle are seized.

The Doctor and Jamie investigate the outside of the IE building. The Doctor uses the transceiver to check with the Brigadier that Zoe and Isabelle actually entered. The Brigadier confirms that they did indeed enter. As they explore they find a railway line that skirts the back of the building.

Gregory has drawn a blank on the circuits. He is dismissed. He opens the wall and demand more data on the Doctor. The machine refuses to give more information but just orders the destruction of the Doctor. Vaughan stands up to the machine. He says unless they share information or he will stop helping them. Reluctantly the machine tells Vaughan that the Doctor has a machine that can help him travel to other planets. Vaughan vows he will destroy the Doctor.

Jamie and the Doctor have snuck into the building. They witness workers carrying crates far beyond human strength. They sneak away.

An alarm is raised. Packer tells Vaughan that the Doctor and Jamie have been spotted. Vaughan tells Packer not to raise full alert but just to close off the area and that they are to be flushed out using Isabelle and Zoe as bait.

As they move around the warehouse, the Doctor and Jamie hear the screams of Zoe and Isabelle. Their unconscious forms are being put into crates to be loaded into the return van. Jamie, furious, attacks the guards. Reinforcements are called for and soon enough Jamie and the Doctor are surrounded by armed guards.

Episode three
Jamie confronts Packer again. Packer goes to hit him but Vaughan calls him off. Vaughan tells Jamie and the Doctor that Zoe and Isabelle were in the building but they left. Jamie protests but the Doctor calmly asks if they can inspect the containers. Vaughan allows but as soon as they all leave to do so, Packer orders the train to leave. Jamie and the Doctor arrive too late. Vaughan suggests that he will accompany them to the factory to do the inspection there.

The Brigadier is worried about the Doctor and Jamie when he receives reports that the two of them plus Vaughan are leaving the building together.

The Brigadier orders them not to be followed and orders one of his subordinates, Jimmy, to go to the factory in a helicopter.

Jimmy watches as Vaughan's car enters the compound. The Brigadier orders Jimmy to hang back as they need to not alert Vaughan's private army which might put the Doctor and Jamie at risk.

The Doctor and Jamie are led into the factory. Vaughan wants to question the Doctor further on the circuits he showed him. As Vaughan shows the Doctor and Jamie into the office, he suggests to Packer that he should go and see if he can convince Watkins to work.

When the Doctor and Jamie enter Vaughan's office they are surprised to see that it is exactly the same as his office in London. Vaughan has become suspicious of Zoe and the Doctor's abilities but isn't surprised or angry Doctor refused to be drawn in it. Vaughan promises the Doctor Watkins' help and leaves. Jamie suspects Vaughan and the Doctor considers him too nice but wonders why he would be offering them Watkins' assistance if he was evil.

Packer is threatening Watkins with harm to Isabelle if he doesn't continue working. Watkins considers it a bluff when Vaughan arrives and assures him it is true. He explains that whatever happens Isabelle will not be freed, she will just come to harm if Watkins refuses to comply. Watkins reluctantly agrees. Vaughan tells Watkins of the Doctor and Jamie and extends the threat to Isabelle to spilling the beans on him.

In the office, the Doctor notices a Deep Space Radio Communication System outside. This causes him to be furthermore suspicious of Vaughan. As they look outside they see Jimmy's helicopter swoop overhead. Packer enters and escorts the Doctor and Jamie into Watkins' presence.

Jimmy reports to the Brigadier that there is no sign of the Do tor or Jamie.

After the Doctor has introduced himself, Watkins says that Travers and Anne told him all about them.

Up in his office, Vaughan tells Packer that the Doctor has been on another planet and has some sort of vessel that he craves. He shows Packer a video screen that shows Watkins, the Doctor and Watkins' conversation.

Jamie begins to talk to Watkins about the TARDIS but the Doctor stifles him. He is aware they are being bugged. He puts a scrambler on the machine.

Vaughan checks all the other cameras - they are all functioning. He realises that the Doctor is quite an adversary and says it is no surprise his allies fear him. Vaughan has vowed not to destroy the Doctor until he knows more of his machine.

Left alone Watson says he is working on a machine called the Cerebraton Mentor, a teaching machine. The Doctor tells Watkins about the involvement of UNIT. Watkins says he has no knowledge of Vaughan's plans and thinks he wants complete control of the electronics industry of the world. The Doctor believes he has bigger aspirations than that. Jamie hears someone coming. The Doctor goes for the scrambler but Vaughan enters and removes it first. Vaughan tells the Doctor that they will make him talk in other ways. He admits he has Zoe and, unless he hands over his machine, she will be hurt. The Doctor and Jamie are led away.

As they are led towards the lifts the Doctor tells Jamie he is scared of lifts and can't even press the buttons. Jamie latches on and enters first. The Doctor wheels around to say that he is ready to hand over his machine already. As he does he distracts Packer, pushes him over and activates the lift. As the lift is in motion he destroys the circuits.

Vaughan berates Packer. Packer reviews a report that the lift is stuck.

The Doctor and Jamie find a door in the lift shaft.

Packer orders all exits to be covered and the lift to be fixed.

The Doctor and Jamie have made it to the roof of the lift. They begin to climb the ladder on the side of the shaft.

Packer has the lift working and orders it to be brought back up.

As the Doctor and Jamie climb they hear the lift approaching.

As the lift arrives Packer and Vaughan find it empty. Vaughan points out that the lift terminates on the roof. Packer sends some men but then also rides to the top to kill them.

The lift starts again but the Doctor and Jamie have reached the roof. They find a fire escape and climb down.

Vaughan is furious about Packer letting them escape and orders their immediate return.

The Doctor and Jamie find their way through the train carriages, hiding underneath when they hear approaching guards. They decide to hide in a sleeper. Jamie wonders if it is the train that contained Zoe and Isabelle. They hear Packer outside and hide in the containers. As Jamie is laying in his he realises that something is alive in his.

Episode four
The Doctor and Jamie emerge from the crates, and overhear guards being ordered to take Zoe and Isobel to the tenth floor.

Vaughn confides in Packer that he intends to use the cerebration mentor to control the Cybermen once they have invaded Earth; he also intends to use the TARDIS as a "getaway car", should he fail.

Vaughn broadcasts over the intercom system to the Doctor that he has ten minutes to surrender or Zoe will be harmed. Using a communicator given him by the Brigadier, the Doctor calls for assistance from UNIT, who assist in rescuing Zoe and Isobel from the room in which they are locked. Realising how dangerous UNIT are to his plans, Vaughn exercises hypnotic control over Major General Rutlidge, and orders him to cease UNIT's investigations.

The Doctor examines photographs of UFOs over the IE factory, and reasons that those ships are bringing cocoons to Earth. He, along with Jamie, sneak into the London IE warehouse, where they witness the emergence of a Cyberman from its cocoon.

Episode five
After witnessing the reactivation of the Cyberman, the Doctor and Jamie sneak back out of the IE warehouse. They return to UNIT HQ and warn the Brigadier that a Cyberman army is invading Earth, and that they are hidden somewhere in London. However, Rutlidge has ordered the Brigadier to cease all investigations against IE. Lethbridge-Stewart intends to gain authority from Geneva, but requires proof to back his reasoning. Isobel offers her expertise as a photographer, but the Brigadier refuses.

Vaughn tests Watkins' device on an awakened Cyberman; however, the alien is driven mad by the machine and escapes into the sewers. Vaughn reveals that in an hour's time the Earth will come under the control of the Cybermen through a micromonolithic circuit built into every IE device; the Doctor discovers this same circuit when he opens up an IE radio, and sets about making a device to block the telepathic signal.

Meanwhile, Isobel, Zoe and Jamie have ventured into the sewers to obtain proof of the Cybermen's presence on Earth. There they find the body of a policeman, who had followed them into the sewers and was subsequently killed by the Cybermen. They then encounter the insane Cyberman, who begins menacingly approaching the intrepid trio.

Episode six
The insane Cyberman walks past the trio and attacks the two other Cybermen. Turner then arrives with Benton, Walters and Perkins. They attack the Cybermen and manage to destroy two of them, but Perkins is killed. They then get Jamie, Zoe and Isobel out of the sewers. The third Cyberman grabs Jamie's leg, but is destroyed with a grenade.

Back at the house, Isobel shows the Brig, Jamie, Zoe and the Doctor the developed photographs, which prove to be worthless because they look to much like fakes.

Watkins perfects his machine and delivers it to Vaughn, but discovers that the Managing Director has been partially cyber-converted, which protects him from bullets. Some UNIT soldiers manage to free Watkins from IE, during which time the Doctor creates a neuristor, which neutralises the Cybermens' hypnotic signals. The Brigadier orders the troops to have one of these taped to the back of their necks.

At dawn, the signal is broadcast, causing people around the world to collapse unconscious. The Doctor's polariser has fallen off and he begins to blank out. The Cybermen exit the sewers and march through London with no resistance...

Episode seven
The Doctor is given a new polariser, and he and UNIT assess the situation, knowing the spaceship that the transmissions are coming from is on the Moon. UNIT decides to use a Russian rocket to destroy the source of Vaughn's signal, while using UK missiles to destroy the incoming Cyberfleet. The Doctor heads off to talk to Vaughn. Captain Turner is sent to Russia to organise the rocket, while the Brigadier goes to the Henlow Downs missile site.

The Doctor goes back to the IE building to try to persuade Vaughn one last time to help his people. The missiles are successfully launched, with help from Zoe, and the Cybermen blame Vaughn for the setback in their plans, announcing that they will use a megatron bomb to destroy life on Earth. The Doctor then asks Vaughn if this is what he wanted - to be the ruler of a dead world...

Episode eight
A furious Vaughn uses the cerebration mentor to destroy the machine in his office. Vaughn calls for Packer, only to see a Cyberman on the screen. Packer rushes in and tells Vaughn that the Cybermen have betrayed them and are taking over. A Cyberman then comes in and kills Packer. The Doctor destroys it with the cerebration mentor. The Doctor persuades Vaughn to now aid humanity instead of trying to defeat it, and they take a helicopter to the factory, where they use Watkins' machine to battle the massed army of Cybermen; UNIT forces arrive later to assist. Vaughn is killed in the skirmish, but the homing signal is successfully shut down.

The megatron bomb is destroyed by a missile, while the rocket destroys the last Cyberman ship, consequently stopping the hypnotic signal. With the crisis now over, and the visual stabiliser circuits now repaired, the Doctor, Zoe and Jamie depart in the TARDIS.

Cast

 * Dr. Who - Patrick Troughton
 * Jamie McCrimmon - Frazer Hines
 * Zoe Heriot - Wendy Padbury
 * Brigadier Lethbridge-Stewart - Nicholas Courtney
 * Tobias Vaughn - Kevin Stoney
 * Isobel Watkins - Sally Faulkner
 * Corporal Benton - John Levene
 * Captain Jimmy Turner - Robert Sidaway
 * Packer - Peter Halliday
 * Professor Watkins - Edward Burnham
 * Lorry Driver - Murray Evans
 * Tracy - Geoffrey Cheshire
 * Patrolman - Walter Randall
 * Gregory - Ian Fairbairn
 * Sergeant Walters - James Thornhill
 * Phone operator - Sheila Dunn
 * Major General Rutlidge - Edward Dentith
 * Workman - Peter Thompson
 * Policeman - Dominic Allan
 * Private Perkins - Stacy Davies
 * Major Branwell - Clifford Earl
 * Sergeant Peters - Norman Hartley
 * Cybermen - Pat Gorman, Ralph Carrigan, Charles Finch, John Spradbury, Derek Chaffer, Terence Denville, Peter Thornton, Richard King

Crew

 * Assistant Floor Manager - Sue Willis
 * Costumes - Bobi Bartlett
 * Designer - Richard Hunt
 * Film Cameraman - Alan Jonas
 * Film Editor - Martyn Day
 * Incidental Music - Don Harper
 * Make-Up - Sylvia James
 * Producer - Peter Bryant
 * Production Assistant - Chris D'Oyly John
 * Script Editor - Terrance Dicks
 * Special Sounds - Brian Hodgson
 * Studio Lighting - Robbie Robinson
 * Studio Sound - Alan Edmonds, Bryan Forgham
 * Theme Arrangement - Delia Derbyshire
 * Title Music - Ron Grainer
 * Visual Effects - Bill King, Trading Post

Cultural references from the real world

 * "Kilroy Was Here" can be seen written in the lift shaft.
 * Isobel plays "Teddy Bears' Picnic" on her gramophone.

Species

 * There are cows in the field where the TARDIS lands.
 * Jamie mentions the Yeti to the Brigadier.

Devices

 * ALGOL is a language understood by computers.
 * The visual stabiliser circuit controls the TARDIS' outward appearance; removing it renders it invisible.

Astronomical objects

 * The Cybermen have a spaceship hidden behind the far side of the Moon.
 * The Cybermen mention encountering the Doctor on Planet 14.

Production

 * Dialogue places this story four years after the events of The Web of Fear. This story is also placed "some months" before Spearhead from Space, according to dialogue in that story.


 * This story had a working title of Return of the Cybermen, which was later changed to The Invasion to keep the Cybermen's reappearance a surprise until episode four. It was originally conceived as a four-part story and got expanded to eight when the next story, The Dreamspinner, fell through.
 * This story marked the debut of Terrance Dicks as Script Editor and his first credited contribution to the series. Dicks would go on to write or co-write a number of episodes, and become best known for his work of writing novelisations for Target Books and eventually contributing to most lines of original fiction based upon the series on into 2008.
 * Together with The Web of Fear, this story was a sort of "test run" for a format switch. For the next two or three seasons, most stories would feature the Doctor working with UNIT to protect humanity on more-or-less modern-day Earth.
 * While the Cybermen would continue to change their appearance on the series, as they had done since their introduction, this story set the basic design for them, first developed for this story by Bobi Bartlett, through the 1980s. Cybermen emerging from cocoons was also used in Earthshock. They also operate in the London sewers in Attack of the Cybermen. A mass invasion of London by Cybermen also features in the Series 2 stories, Rise of the Cybermen, The Age of Steel, Army of Ghosts and Doomsday, and in the Doctor Who Magazine comic The Flood.
 * Cybermats were to have appeared in this story.
 * It was during filming of this story that Frazer Hines announced his intention to leave the series.
 * Zoe makes no appearance in episode three of the story as Wendy Padbury was on holiday during the week when it was recorded. Similarly, Jamie appears only in a pre-filmed insert in episode eight as Frazer Hines was due for a break.
 * A black and white shot of a Cyberman, with two others behind, walking down the steps of St. Peter's Hill, with St. Paul's Cathedral in the background, accompanied the Radio Times programme listing for episode one, bearing the title Invasion and with the accompanying caption "Dr. Who starts a new adventure today at 5.15 — one that will bring him face to face with some of his deadliest enemies, the Cybermen".
 * The following piece of behind-the-scenes information appeared at the foot of the Radio Times programme listing for episode five: "For this Dr. Who story more filming was done on location than ever before, and the production team were fortunate to have the co-operation of both the Army and Air Force on scenes that involved such equipment as jeeps, a transporter plane, a three-ton lorry, and a rescue helicopter."
 * Nicholas Courtney reprises his role as Lethbridge-Stewart, now promoted from Colonel to Brigadier, from The Web of Fear.
 * John Levene (Benton) previously appeared as a Cyberman in The Moonbase and as a Yeti in The Web of Fear. He was initially contracted to play a Cyberman in The Invasion, but landed the role of Benton after the actor originally cast – who shall remain nameless – was fired by Douglas Camfield for continually turning up late for filming, causing the planned shooting schedules to be changed.
 * John Levene (Benton) was uncredited on-screen for episode five, but was credited in Radio Times.
 * Peter Halliday also provided, uncredited, the voices of the Cybermen in episodes six to eight and of the Cyber Director — hidden in a concealed compartment in Vaughn's office — in episodes two and five to eight.
 * Norman Hartley (Sergeant Peters) was credited as "Sergeant" in Radio Times for episode eight.
 * The actors playing the Cybermen were credited on-screen, but not in Radio Times.
 * In the DVD's animated version of episode one, the words "Bad Wolf" (the story arc of the 2005 series) are written on Isobel's wall as an in-joke.
 * Also in the animated episode one, the car that the Doctor, Jamie and Zoe hitch a ride with after the lorry driver is shot has the licence plate H 23 63, which is a reference to the date of the original broadcast of An Unearthly Child, the very first episode of Doctor Who, on 23 November 1963.
 * Additionally, the animators got Zoe's costume wrong; for the beginning part of the missing episode one, Zoe would have worn her catsuit from The Mind Robber and she would have changed when Isobel got her fixed up with "some proper gear".
 * The episode was intended to prove that Earth-based stories could be produced cheaply and effectively. Ironically, it was the most expensive Doctor Who episode ever produced when made, and remained so for several years.
 * Originally, Professor Travers and his daughter Anne were to appear, but were replaced by Isobel and her uncle when Mervyn Haisman and Henry Lincoln refused to grant the rights. The DVD's production subtitles claim they were granted rights to the characters, but as the characters became less involved in the story, they thought it was not worth including them. The characters are mentioned in dialogue, however: Isobel lives in Travers' former house in London, and Professor Watkins mentions that Travers was getting "past it," so he persuaded him to live in America with Anne.
 * The prologue of PROSE: Iceberg opens during the Cybermen invasion in this story. The Cybermen in that novel are said to be from Planet 14, which was first mentioned in The Invasion by the Cyber-Planner. COMIC: The World Shapers also picks up on the Planet 14 reference, though it explains it away in a very different way. Since The Invasion takes place in either in the late 1960s or 1970s (see UNIT dating controversy) and no other televised Cybermen story had taken place prior to 1986 (the date of The Tenth Planet), the Doctor must have met the Cybermen before in an untelevised story. The Cybermen did have access to time travel technology, so that conclusion is not an absolute certainty. In 1986, the Cybermen on Mondas appeared to be of a less sophisticated design and did not give any indication of having a fleet of ships. The Cybermen in the 1970s seem to be more advanced and do have a fleet of ships.

Influences

 * The influence of the various spy thriller films and television shows which were popular at this time are very clear. Tobias Vaughn is similar to the supervillains featured in the James Bond films and The Avengers. The Doctor acting as advisor to a military group dealing with an otherworldly menace is highly reminiscent of the Quatermass serials. Specifically, the plot of The Invasion has some similarity to , though not as much as some other Doctor Who stories, such as Spearhead from Space.

Ratings

 * Episode one - 7.3 million viewers
 * Episode two - 7.1 million viewers
 * Episode three - 7.1 million viewers
 * Episode four - 6.4 million viewers
 * Episode five - 6.7 million viewers
 * Episode six - 6.5 million viewers
 * Episode seven - 7.2 million viewers
 * Episode eight - 7.0 million viewers

Filming locations

 * The cow pasture in which the TARDIS materialises was located at Williamstrip Farm at Coln St Aldwyns. Professor Watkins' house was located at St James' Gardens in Kensington.
 * Kingston Minerals in Kempsford served as the IE compound, while the compound's roof was actually that of the Associated British Malsters' Guinness factory in Wallingford, Oxfordshire.
 * Additional scenes at IE were filmed at the Guinness Factory in London.
 * The canoe sequence was filmed at Lisson Grove and the helicopter sequence at Denham Aerodrome in Buckinghamshire.
 * Other scenes were filmed at various locations in Gloucestershire.
 * Ealing Television Film Studios, Ealing Green, Ealing
 * Lime Grove Studios (Studio D), Lime Grove, London

Production errors

 * In episode five, the panel concealing the Cyber Director struggles to close.
 * The Cyberman falling from the roof of an IE building in episode eight is clearly an empty costume.
 * In episode eight, the strings that make the Cyber Director's "head" twist are clearly visible.
 * In episode four, the Doctor and his companions claim to have seen a ship on the moon — when they didn't. (In the DVD's animated episode one, a ship was added to cover this up.)
 * The Cybermen wear silver painted tennis shoes.
 * In episode eight, Wendy Padbury fluffs her line regarding the distance to the Cyber Ship, quickly correcting "30—" to say "50,000 miles."
 * Throughout, Brigadier Lethbridge-Stewart's moustache changes size and shape.
 * Some episodes of the story were broadcast in such an amplitude that sometimes makes it hard to make out what the cast were saying.

Continuity

 * Tobias Vaughn returns in PROSE: Original Sin, in which it is revealed that not only did he survive by transferring his mind into a cybernetic body, but funded the development of BOSS, Operation Golden Age, and Professor J.P. Kettlewell's robot, and influenced the expansion and policies of the Earth Empire.
 * At this point, the Cybermen are aware of the TARDIS ("he has a machine"), but make no reference to its nature or that he is a Time Lord.
 * Isobel's photographs of the Cyberman invasion were later derided as fakes and she became a standing joke on Fleet Street. The journalist James Stevens was highly dubious of her claims that the Earth had been invaded by "robot men from outer space." She was threatened by a man with a lisp and her boyfriend left her as his career was at risk because of their relationship. (PROSE: Who Killed Kennedy) However, her boyfriend was not Jimmy Turner as they later married. (PROSE: The Scales of Injustice)
 * The Cybermen killed in the conflict are claimed by UNIT and later used to create weapons effective against Cybertechnology (TV: Death in Heaven).

DVD releases

 * Released as Doctor Who: The Invasion, the DVD makes use of animated versions of the missing episodes one and four that were made by Cosgrove Hall, which had previously made Scream of the Shalka for the now-defunct BBCi website.

Release dates

 * Region 2 - 6 November 2006
 * Region 4 - 3 January 2007
 * Region 1 - 6 March 2007

Features

 * Commentary on episode one by James Goss (bbc.co.uk), Steve Maher (Cosgrove Hall films) and Mark Ayres (audio cleanup).
 * Commentary on episodes two to eight by Frazer Hines, Wendy Padbury, Nicholas Courtney and Chris D'Oyly John.
 * Flash Frames - A featurette about the creation of the animated episodes one and four, including interviews with the animation team at Cosgrove Hall.
 * Love Off-Air - An affectionate tribute to the people dedicated enough to capture the soundtracks of Doctor Who in the 1960s, enabling the recreated episodes on this DVD.
 * Trailers - Two animated trailers.
 * Character Design - Showcasing Steve Maher's character design drawings and animation tests.
 * Evolution of The Invasion - Cast and crew recall the making of The Invasion, featuring contributions from Padbury, Hines, Courtney and D'Oyly John, plus Kevin Stoney (Vaughn), Sally Faulkner (Isobel), Peter Halliday (Packer), Edward Burnham (Watkins), Ian Fairbairn (Gregory) and Terrance Dicks (Script Editor).
 * VHS Links - Nicholas Courtney's links from the 1993 video release of The Invasion
 * Photo Gallery - Includes music by Don Harper and John Baker as well as special sound by Brian Hodgson.
 * Production Subtitles

The animated episode one on the DVD release makes some changes to the episode, as noted on the commentary:
 * After the TARDIS is attacked, a ship goes across screen (put in by the animators to cover a plot hole).
 * The sequence after the Doctor leaves the van that takes them out the compound is shortened.
 * The words "Bad Wolf" are put on the wall where Isobel Watkins leaves notes, making reference to the Bad Wolf meme.

Notes:
 * Editing for the DVD release was completed by the Doctor Who Restoration Team.

VHS release
This story was released as Doctor Who: The Invasion in 1993 as a double video pack, with an introduction and linking material by Nicholas Courtney to cover the missing episodes one and four.

Release dates

 * UK June 1993
 * PAL - BBC Video BBCV4974


 * US June 1995
 * NTSC - CBS/FOX Video 8251
 * NTSC - Warner Video E1273

Audio releases
This story was released as Doctor Who: The Invasion as part of the BBC Radio Collection. It includes the original soundtrack of the serial with linking narration by Frazer Hines. It also includes a bonus interview with Hines.

It was first released on 1 November 2004 in the Cybermen box set (ISBN 0-563-52508-8), a special 3-CD tin which also contained the soundtrack of The Tenth Planet and a bonus disc. It was subsequently released individually on 9 January 2006 (ISBN 978-0-563-52327-7). It is scheduled to be re-released as part of Doctor Who: The Lost TV Episodes - Collection Five on 2 August 2012 (ISBN 978-1-4084-6755-8).

Unofficial releases
Loose Cannon Productions have made a reconstruction of the missing episodes one and four, using audio recordings, authentic pictures, composite pictures, pictures from other stories and specially created material. (Note: The surviving episodes are not included on the recon.)

Although Loose Cannon Productions and Cosgrove Hall were working from the same scripts and audio recordings, their visual interpretations of the episodes are very different and it is interesting to compare the two.

Features

 * Celebrity Introduction by Kevin Stoney (Tobias Vaughn)
 * Production Featurette
 * An Interview with Kevin Stoney (also includes clips from many of his television and film appearances)
 * A re-enactment of the scene of Cybermen descending the steps of St. Peter's Hill near St Paul's Cathedral, using Earthshock-style Cybermen, and comparing the re-enactment with the original.