Doctor Who and the Silurians (TV story)

Doctor Who and the Silurians was the second story in season seven of Doctor Who. It introduced several important recurring elements to the programme, including Bessie, the Silurians and, behind the scenes, colour videotape recording and colour separation overlay. The story is technically "missing" because those videotape masters were wiped. However, it is still viewable today because it was recorded to several different other formats.

Casting was notable for the first appearance of recurring Doctor Who guest actors Peter Miles, Paul Darrow and Geoffrey Palmer, as well as noted actor Fulton Mackay's lone turn on the programme. Silurians also had an unusual number of crew cameos, with Terrance Dicks, Barry Letts and, most prominently, Trevor Ray showing up at the Marylebone station scene. (DWM 222)

Due to a miscommunication with the graphics department who created the credits sequences, it was the only Doctor Who television story to have "Doctor Who" in the title. As such, it is often referred to simply as The Silurians, its originally intended broadcast title.

Synopsis
At Wenley Moor nuclear research facility, they're experiencing technical difficulties. The source is something old, the former rulers of the Earth, and they have awoken.

Episode one
Two potholers make their way down a metal rope ladder into a cave with a remarkable amount of stalactites. They are delighted at the sight of its majesty, but a loud roar spooks both of the men and incites them to find out where it came from. As they continue down a tunnel, another roar bellows from the distance. When one of the, rounds a corner, he is met with the hostile face of a reptilian creature. The leading potholer is mauled to deat. The other man dashes over to find the body. He sees the creatures and runs away screaming.

In a UNIT garage, the Doctor is merrily working to restore a bright yellow vintage car, which he had been given at his request, humming the first lines of Jabberwocky. A license plate emblazoned "WHO 1" lays in front of him as he sits beneath the car's undercarriage fixing its parts. Liz enters the room and calls for him. The Doctor doesn't hear her, and continues to tinker away at his vehicle, which he has affectionately nicknamed "Bessie", telling it to cooperate when it becomes a hassle to repair its chassis. Liz approaches the Doctor directly and gets him to emerge from underneath Bessie. She is sceptical to think he can get it running, but the Doctor is quick to defend his car, stating it has great character and he was very lucky to get it. The Doctor plans to take it for a test drive, though he seems to have left out a metal hoop, which he looks at with confusion. Unable to recognise the part, he tosses it aside. Liz informs the Doctor the Brigadier has an urgent message for the two of them while he's away investigating scientists. They are to go to Wenley Moor forthwith to attend a meeting. Seeing it as beneath him to comply, the Doctor claims he's too busy, and goes back to work on Bessie. However, Liz tries to make it sound like less of an order by noting that Wenley Moor is famous for its caves. Eager to give Bessie a trial run, he submits. The Doctor kisses his hand and plants it on Bessie's radiator. Her engine starts and the car rumbles to life.

At the Moor the director is speaking about the issues regarding their facilities. He resents UNIT's presence and feels it will interfere with the working of the plant. One of UNIT's soldiers notifies Lethbridge-Stewart that the Doctor and Liz Shaw have arrived and he leaves to meet them. The Doctor isn't pleased to be called in for a simple meeting, but follows the Brigadier and Liz back to the conference room with the hope it was important. Shortly after the trio enters to the conference room the director concludes the meeting. Brigadier introduces his colleagues to the director, Doctor Lawrence, Doctor Quinn, his number two, and Major Baker, station security officer. The group tells the trio they are at an experimental nuclear power for research centre for a cyclotron; a proton accelerator. They are trying a new process to convert nuclear energy directly into electric power. It is experiencing mysterious power drains and a high incidence of mental breakdowns, absenteeism, and accidents. This has stagnated their research program and Lawrence refuses to let it continue. UNIT have been called in to investigate. Brigadier orders Baker to triple check security arrangements, puts Liz in charge of inves the issues with personnel and the Doctor is given charge of the scientific troubles. The Brigadier establishes the conference room as his working HQ so Lawrence will not complain that UNIT is interfering with the operation of the centre. After everyone but Baker and the Brigadier have left the room, Baker confides to him that he believes there is a saboteur from the inside.

Quinn shows the Doctor and Liz the heart of the cyclotron. The Doctor is bemused to learn it is still being tested while power failures are happening. If one occurred at a critical time, when the machine was in use, it could incite a massive atomic explosion equal to a nuclear bomb. Quinn replies it is up to the director to shut down the cyclotron, whom the Doctor knows is being too stubborn to halt the research. Suddenly, Liz becomes dizzy and grips her forehead. The Doctor sees Liz in pain and voices concern. She says she is okay, then departs to examine her reports of personnel. Quinn assumes his duties at a booth while the Doctor commends the scientists for constructing an underground accelerator. Quinn expresses his like of potholing to the Doctor because the caves intrigue him, but he isn't so keen anymore as recently, one of the workers at the centre was killed while exploring the caves with a companion on their day off. He says they have brought in Doctor Meredith from a local hospital to treat the survivor, Spencer, who is still in sick bay. Quinn feels the status of his condition and what happened to him are being covered up. The Doctor grows suspicious. He asks if the power losses follow a pattern. When Quinn says the scientists think of them as random, the Doctor requests to look at the reports. Quinn hands over the log showing the power losses. The Doctor notices the log is incomplete. Quinn summons Miss Dawson and asks who was responsible for maintaining the log. She states it was Spencer, the same man who has been kept in sick bay, leaving no one to update it. Despite this explanation, the Doctor finds it more complicated than the log falling out of date- he's discovered some pages have been torn out entirely. Quinn and Meredith exchange troubled looks.

In the medical wing, Liz speaks to Doctor Meredith about the recent outbreak of mentally-affected patients. He does not understand why UNIT have been called in. They are joined by the Doctor. He wishes to see Spencer, but Meredith won't allow it; Spencer is due to be moved to the local hospital and the Doctor has no authority to warrant a visit. The Doctor briskly asserts his power as an associate of UNIT. Meredith concedes, but warns him the visit is at his own risk.

The group enters the sick bay to find Spencer scribbling with a marker on the walls. A member of the medical staff is supervising him, who walks out to allow Doctor Meredith to take over. Spencer has emerged from a coma and has previously tried to throttle Meredith. He's left Spencer to mark up the room's walls, since it's all that keeps him quiet. The Doctor approaches him to see if he can communicate. Liz warns him to be careful. He tries to speak to Spencer, but the man jumps and panics, immediately wresting his hands around the Doctor's throat and forcing him down onto a cot. Liz and Meredith rush to subdue him, but the Doctor tells them to stop and pries Spencer's hands loose and quells his violent reaction. Spencer resumes his scribbling while the Doctor nurses his neck. He remarks that a great fear has caused his mind to regress millions of years back.

Off in a corner of the cyclotron testing room, Quinn argues with Miss Dawson, his assistant, when she protests that they should stop "them" from taking the power. Dawson pleads with Quinn to order "them" to stop. He says he has already tried and they have refused to listen. She implores him to tell Baker or the Brigadie. He refuses. When she warns him of the risk he states that the promise of potential knowledge gain has outweighed the risk.

The Brigadier and Baker discuss UNIT's security clearance While checking the security reports. Baker says he has no central intelligence records of the Doctor. Lethbridge-Stewart states the Doctor as his responsibility. The Doctor returns to the conference room and Lethbridge-Stewart excuses Baker, giving him a chance to warn the Doctor he's trying to run a security check.

Lawrence checks on Quinn before the next test. Quinn states that all is normal. Quinn asks to run some supplementary tests but Lawrence blocks it as they are already behind schedule. The experiment begins. One of the scientists, Roberts, seems in a daze.

The Doctor has explained his discoveries to the Brigadier. The Brigadier is sceptical of any link. They are interrupted by a power failur.

The Doctor charges into the cyclotron testing chamber and learns it undergoing a dangerous fluctuation in power. As the operators attempt to stabilize the nuclear reactions, they shut down two sectors. Roberts is due to close down the third sector but suddenly he goes completely still. Dawson tries to get his attention, but he attacks her. The Doctor and Brigadier grab hold of him and rescue Dawson, then the Doctor manages to stabilize sector three.

The Doctor returns to Liz to check the medical patients' records. There has been a startling outbreak of neuroses in the cyclotron room, where she previously felt ill. She describes how she felt as oppression and horror. The Doctor thinks it doesn't have anything to do with the cyclotron itself, but the caves. That room is deepest and closest to the cave systems. He also believes the sickness affects only some people. The two look at the reports of Davis's death. His death was caused by a fracture to his cranium but unusual abrasions were found on his side that resembled scratches or claw marks.

Now changed into suitable clothes for exploration, the Doctor makes his way into the caves, where he hears a loud roar and goes to investigate. He finds a cave hammer and a rope abandoned from the last expedition. He hears the roar again, only closer, and draws nearer to the sound until he is in the same place as the original attack. He almost leaves, but hears the roar directly behind him. He turns to see a dinosaur, and it instantly bears down on him.

Episode two
A beeping sound calls the creature off. The Doctor pursues the creature and finds a huge footprint embedded in the mud.

Liz has told the Brigadier about where the Doctor is. The Brigadier is angry that he has put himself into danger and that Liz let him. Baker has organised a search party. It is called off when the Doctor reappears back at HQ.

Lawrence is questioning Quinn as to why the power supply is still failing. Lawrence tells Quinn of the Doctor's disappearance in the caves. Quinn seems worried until he is told that he has been found and no search party will be deployed.

The Brigadier does not believe the Doctor has seen a dinosaur. Baker speculates that whoever has been draining the power may have mocked something up to scare people away. It is decided that they will all go and explore. The Doctor is bemused when the Brigadier and Barker talk about how to arm themselves.

The Doctor leads the way in the cave system. He seems confused when the footprint in the mud has gone. They hear a rumbling and Barker runs off with UNIT soldier Captain Hawkins in pursuit. Barker sees a figure further down in the cave system. He shoots above the figure's head but the bullet ricochets down and strikes it. The dinosaur them appears and attacks Barker. Hearing the screams the rest of the party run to his aid. They find Barker conscious but confused. Hawkins finds blood on the floor and he and the Brigadier follow it. The Doctor takes a sample of the blood back to HQ for testing.

A wounded creature emerges into the moorland.



The Doctor has discovered that the blood sample has many similarities with the blood of reptiles. The Brigadier enters and says he has lost tracking the creature. He is to summon more men and continue the search the following day. The Doctor lies and says that results on the blood have proved inconclusive. The Brigadier tells everyone that Barker is OK and has minor concussion. The Doctor wonders why the creature killed it's first victim but was called off from himself and Barker. The Doctor theorises that their are two types of creature: one large and ferocious, the other small, more intelligent and less hostile.

The wounded creature stumbles into a barn.

Lawrence is furious with Ms Dawson when she tells him that Quinn has disappeared. Lawrence accuses him of being more interested in the book that he is writing than the project. The Doctor enters and is keen to question Quinn too.

Quinn is in the cave system. He reaches a certain point and a door in the cave opens for him. He is led, in a trance, to a console. When he comes to his senses he warns the creature he is talking to through a computer system of the UNIT soldiers. He is told that it is too late and that one of their men have injured one of their kind. Quinn says that the UNIT soldiers will withdraw if they stop taking the power. The creature refuses. The creature says Quinn must get their injured number back. Quinn refuses. He is told that they will not share their scientific secrets with him unless he does. He relents. He is given a summoning device, put back in a trance and sent off.

The next morning a farmer discovers the creature in his barn. He calls for his wife to call the police. The creature wakes up and attacks the farmer.

The UNIT soldiers have arrived and are to search for the creature. Lawrence enters and coldly tells the Brigadier that his men are not helping at all. The Doctor enters and says that he has investigated all the machinery and there is nothing wrong. The power is being affected by an outside agent. The Doctor recommends the closing of the base. Lawrence refuses and says he is going to go over the Brigadiers head to get him to leave the site. Lawrence leaves and the Brigadier gets a phone call informing him of the farmer's death. The police have noticed claw marks on his body.

Later the Doctor, the Brigadier and Liz are investigating the farmer's body. He suspects that the farmer cornered the creature causing it to attack. He observes that the claw marks are smaller than the ones on Barker. They are also not the main cause of death. The farmer died of heart failure.....of fear. The Doctor and the Brigadier are to go and interview the wife who has been hospitalised with shock whilst Liz is to stay and carry out some forensic tests.

The wife is beside herself with shock. The Doctor draws a picture of a creature. The wife states this is what killed her husband. The Doctor asks where the creature is. She responds "In the barn." The Doctor and the Brigadier realise the creature is still there.

Liz is doing her tests whilst the creature approached her. She turns to see the creature just as it attacks her.

Episode three
The creature attacks Liz before going to escape. It is blocked by a police guard and turns back.

Dawson comes to Quinn's cottage. Quinn is frantically looking for the tracker given to him in the caves. He tells Dawson about the wounded creature and Dawson tells him about the UNIT soldiers rushing off to the farm. Quinn thinks the creature must be there and heads off.

The Brigadier, the Doctor and the UNIT soldiers storm the barn. They find Liz unconscious. They can't find any trace of the creature despite the fact that the door was bolted from the inside. Liz starts to regain consciousness. Hawkins has found a back door which the creature must have escaped through. The Brigadier orders a full search around the barn. The Doctor asks Liz what the creature looked like. She reports it was a reptile that walked upright. Quinn arrives in the barn. He says he was just passing and saw all the fuss. He tries to question Liz as to what the creature looked like but the Doctor doesn't allow her to tell him. Quinn, seeing there are too many people around, tries to slope off but the Brigadier asks for his help with local landmarks.

The UNIT soldiers have started their full search using helicopters.

Quinn offers his help and then leaves. The Doctor asks him if he could give Liz a lift back to the headquarters. Quinn changes his story and says he needs to head into town to the garage first. Once he has left Liz points out that the barn isn't on Quinn's way from the cottage to the headquarters- so why was he passing?

Quinn pulls up in the middle of nowhere and switches on the tracker. The search dogs in the area go crazy. A helicopter passes at low altitude. Quinn hides the tracker and gets back in the car.

The Doctor and the Brigadier join the search. Hawkins tells of a man seen in the same place as a strange noise was detected. The Doctor and the Brigadier head off to explore.

Quinn has moved on and turns the tracker back on. The beeping builds up rapidly. The creature is approaching Quinn rapidly from behind.

All of a sudden the noise stops. The Doctor and the Brigadier have reached the area where it was emanating from. They find the tracks of a reptilian biped and car tracks. The Brigadier focuses his search to this area.

Back at headquarters, Baker has gained consciousness and is eager to join back up with UNIT. Liz says he is not well enough yet. He remembers everything that happened in the cave up until the moment he was attacked. He is insistent he wants to join back up but Liz refuses. As soon as she leaves he dresses himself.

The doorbell at Quinn's cottage rings. It is the Doctor. He questions why Quinn is neither at the garage nor at headquarters. Quinn tires to pacify him and send him on his way but the Doctor forces his way in. He notes how warm it is in the cottage. Quinn says the thermostat is broken. The Doctor comments on it being like the reptile house at the zoo. This rattles Quinn who asks the Doctor to leave. The Doctor tells Quinn to let him help but Quinn just shows him out.

Liz and the Doctor look through Quinn's files. The Doctor opens a locked cabinet and finds a strange ball and some notes. Liz inspects the ball and sees it is some kind of globe. The Doctor inspects it and says it is a representation of the world before the Great Continental Drift, two hundred million years ago. He has also deduced that the notes are calculations to do with the age of the Earth during it's Silurian period. Dawson interrupts them. The Doctor reveals his suspicions to her and implores her to tell him what she knows. She is about to tell all when they are interrupted by the Brigadier. She leaves. The Doctor is furious at the Brigadier.

Quinn's doorbell rings insistently. He leaves it. Whoever it in lets themselves in. It is Dawson. She tells of the Doctor and the fact he knows more than they thought he did. She implores him to tell someone. He refuses saying the Doctor will want to steal the scientific discoveries that he will gain. She gets cross and says he has t gained any scientific knowledge. He confides he has one of the creature locked up and isn't going to return it until it gives him the knowledge he requires.

In a meeting at headquarters, the Doctor confirms that the interference affecting the power is coming from the caves. Baker enters and demands they move in the caves in force. The Doctor disagrees. The Brigadier sends Baker back to the infirmary. Lawrence is peeved that the Brigadier is arresting his staff. The Brigadier says he agrees with Baker and that they should use force in the caves. Lawrence says he has very little time to take action on this as he has sent for the Permanent Under Secretary who is coming to inspect UNIT's operation and potentially call the Brigadier back. The Brigadier pursues Lawrence arguing. The Doctor heads off to Quinn's cottage to convince him to trust him.

Quinn's doorbell again goes unanswered. The Doctor lets himself in and looks round. He finds Quinn dead with the tracker in his hand. He turns it on. A reptilian humanoid enters the room and confronts the Doctor.



Episode four
The Doctor attempts communication, only for the Silurian to run away. Baker, still convinced that the answer lies in the caves, overpowers the UNIT soldier, Hart, guarding the sickbay and enters them by himself. He is soon captured by the Silurians and interrogated as to the capabilities of the humans. The Doctor and Liz explore the caves following Baker's route and open the entrance to the Silurian base with Quinn's signal device, where they find Baker in a locked cage. He tells them that they must warn the surface.

The Doctor and Liz leave undiscovered, but not before they see a Silurian being revived from hibernation by a machine, explaining the energy drains that the reactor has been experiencing. Meanwhile, Masters, the Permanent Under-Secretary in charge of the centre, arrives for a personal inspection, and Lawrence complains to him about UNIT's interference. The Doctor decides to tell them all about the Silurians in the caves, urging a peaceful contact instead of the Brigadier's proposed armed expedition. However, this falls on deaf ears when Miss Dawson reveals that Quinn was killed by the Silurian he held captive.

The Doctor goes to warn and reason with the Silurians, but they put him in a cage as well. An older Silurian seems to be willing to listen to the Doctor, but a younger one wants to destroy the humans and retake the planet. The UNIT troops soon find themselves trapped, with stone walls inexplicably appearing to block off their passage. The younger Silurian attacks the Doctor psychically with a glowing third eye.

Episode five
The older Silurian sees what is going on and stops the younger Silurian. He tells the Doctor how their race retreated underground and their lives in suspension when they saw the Moon approaching Earth millions of years before, with their scientists calculating that the Moon would draw off Earth's atmosphere, destroying "all life". The hibernation mechanism never woke the Silurians as the arrival of the Moon never created the predicted catastrophe; instead, the Moon was captured in Earth's orbit. The Silurians did not revive until a new power source—the nuclear reactor—was discovered.

The Doctor manages to persuade the older Silurian to release the Brigadier and his men, but the younger Silurian orders Baker infected with a bacteria before he is released. When the older Silurian discovers this, he releases the Doctor, giving him a canister of the bacteria culture so he can discover a cure. The younger Silurian kills the older one for this act.

At the centre, the Doctor warns everyone to stay away from Baker, who collapses with the infection. Masters, however, decides to return to London, unaware that he has also been infected. Baker is taken to a local hospital without the Doctor's knowledge and dies there. "The first one", the Doctor grimly notes.

Episode six
The Brigadier holds Baker's doctor and nurse at gunpoint to prevent them from leaving and spreading the disease while the Doctor returns to the centre to work on the cure. The Brigadier and Liz try to warn London, while all of the centre's staff are inoculated with a stopgap vaccine.

All, that is, except for Lawrence, who refuses. Masters, in the meantime, has reached London and eludes the search parties desperately looking for him. The illness begins to spread and the deaths begin, the infection even reaching France. Lawrence eventually dies from the bacteria, complaining in his last moments that the affair has ruined his career.

The young Silurian decides the Doctor must be killed before he finds a cure. The Doctor has indeed found one, and as he writes down the formula, the Silurians attack the centre and stun him with their third eyes and take him away.

Episode seven
Liz, however, discovers the formula and it is soon being mass produced and distributed. The Silurians have a back-up plan, however. They intend to use a weapon to destroy the Van Allen Belt and make the Earth's environment hostile to humankind, and will force the Doctor to connect the reactor to provide power to the weapon. UNIT troops are lured into the caves and commence a battle with the Silurians while the younger Silurian takes the Doctor to the reactor control room along with Liz and the Brigadier. The Doctor, however, overloads the reactor and tells the younger Silurian that the area will be irradiated for at least 25 years. The Silurians disengage from the battle with UNIT and reenter the caves to hibernate until the danger has passed. Since the mechanism is faulty, the younger Silurian will stay awake to operate it and sacrifice his life. The Doctor and Liz, meanwhile, repair the reactor, and go to the underground base, where the younger Silurian realises he has been duped into sending his race back to sleep. He attacks the Doctor in a rage, but is killed by the Brigadier.

Later, on Wenley Moor, the Doctor tells Liz that he proposes to revive the Silurians one by one and try to reach a peaceful compromise between them and humanity. However, the Brigadier has other orders, and the Silurian base is blown up. The Doctor is horrified at this act of genocide, but Liz tells him that the Silurians would never have agreed to come to terms. The Doctor, still disgusted, drives away.

Cast
This serial had a sizeable cast of background characters, doubles and extras that did not receive on-screen credit.
 * Doctor Who - Jon Pertwee
 * Liz Shaw - Caroline John
 * Brigadier Lethbridge Stewart - Nicholas Courtney
 * Dr. Quinn - Fulton Mackay
 * Major Baker - Norman Jones
 * Dr. Lawrence - Peter Miles
 * Miss Dawson - Thomasine Heiner
 * Dr. Meredith - Ian Cunningham
 * Roberts - Roy Branigan
 * Spencer - John Newman
 * Davis - Bill Matthews
 * Captain Hawkins - Paul Darrow
 * Doris Squire - Nancie Jackson
 * Squire - Gordon Richardson
 * Silurians - Pat Gorman, Paul Barton, Simon Cain, John Churchill, Dave Carter
 * Silurian Voices - Peter Halliday
 * Masters - Geoffrey Palmer
 * Sergeant Hart - Richard Steele
 * Travis - Ian Talbot
 * Old Silurian - Dave Carter
 * Young Silurian - Nigel Johns
 * Private Robins - Harry Swift
 * Silurian Scientist - Pat Gorman
 * Corporal Nutting - Alan Mason
 * Private Wright - Derek Pollitt
 * Hospital Doctor - Brendan Barry

Crew

 * Writer - Malcolm Hulke
 * Title music by Ron Grainer and BBC Radiophonic Workshop
 * Incidental music composed and conducted by Carey Blyton
 * Designer - Barry Newbery
 * Producer - Barry Letts
 * Director - Timothy Combe
 * Film Cameraman - Fred Hamilton
 * Film Editor - Bill Huthbert
 * Visual Effects - James Ward
 * Script Editor - Terrance Dicks
 * Costumes - Christine Rawlins
 * Makeup - Marion Richards, Teresa Wright
 * Studio Lighting - Ralph Walton
 * Sound - John Staple
 * Special sounds by Brian Hodgson & BBC Radiophonic Workshop
 * Videotape Editor - Sam Upton

Story notes

 * This story had a working title of The Monsters (also sometimes referred to as Doctor Who and the Monsters).
 * Bessie (on-screen numberplate WHO 1) is seen for the first time. Its real life numberplate was MTR 5, as WHO 1 was not available — having already been registered elsewhere. Special WHO 1 numberplates were made and used on the car when filming on private ground or on the public highway with permission from the police.
 * This is the first use of CSO (Colour Separation Overlay) in Doctor Who.
 * The unusual music in this story was conducted by Carey Blyton and featured clarinets, recorders, cellos and horns.
 * This is the only serial title to break the "Doctor Who" naming taboo (i.e. directly identifying the character by the incorrect name "Doctor Who"). Previously, an episode of the serial The Chase also broke the taboo by being titled "The Death of Doctor Who".
 * The title of the story came about because most of the scripts (up to this point) were titled Doctor Who and the... While the Doctor Who and the... was ordinarily left off the titles, this time, the title retained the words. To avoid this occurrence in the future, the Doctor Who and the... was left off the scripts in the following stories. The practice was, however, retained for the Target Books novelisations, although when the time came to adapt this story, a different title was chosen (see below).
 * There are non-speaking cameo appearances by members of the production team, including Barry Letts and Terrance Dicks as rail passengers and, most prominently, Trevor Ray as a ticket collector struck down by the Silurian bacteria, in the location scenes shot at Marylebone Station in London.
 * The cave creatures are named Silurians on the presumption that they come from the Silurian Period. It was known that reptiles had not evolved by the Silurian Period, so technically the name is a misnomer. Nevertheless the name was kept because it sounded good for the story.
 * When the Silurians return to hibernation at the end of the episode, they say they will be revived in fifty years. While the year of this episode is not given, it was broadcast in 1970. Fifty years later would be 2020, which coincides with the events of TV: The Hungry Earth.
 * With Mission to the Unknown, The Mind of Evil, The Daemons, The Sea Devils, The Sontaran Experiment, Genesis of the Daleks and Midnight, this is one of only eight televised stories in the history of Doctor Who not to feature the TARDIS.
 * For episodes one, three and four, Carey Blyton is given the credit "Incidental music by". For episode two and episodes five to seven, the credit is given as "Incidental music composed and conducted by".
 * Despite its 1970 airdate, this was the final story in the series to be filmed during the 1960s, having begun location filming in November of 1969. (DOC: Now and Then) As such, this story and Spearhead from Space are the only two of that sort to have been shot in full color.

Ratings

 * Episode 1 - 8.8 million viewers
 * Episode 2 - 7.3 million viewers
 * Episode 3 - 7.5 million viewers
 * Episode 4 - 8.2 million viewers
 * Episode 5 - 7.5 million viewers
 * Episode 6 - 7.2 million viewers
 * Episode 7 - 7.5 million viewers

Filming locations

 * Marylebone station, Marylebone, London (Where the disease breaks out)
 * Dorset Square, Marylebone, London (Where Masters gets out of the taxi)
 * Sheephatch Farm, Sheephatch Lane, Tilford, Surrey (Location of the farm the Silurian hides in)
 * Milford Chest Hospital, Tuesley Lane, Milford, Surrey (Wenley Hospital)
 * Hog's Back Transmitter Station, Hog's Back, Guildford, Surrey (Exterior shots of Wenley Moor Nuclear Power station)
 * Melcombe Place, Marylebone, London (Masters hails a taxi from here)
 * Swancombe House (walkway), St. Ann's Road, Shepherd's Bush, London (Masters succumbs to the infection and dies at this location)
 * Hankley Common, Rushmoor, Surrey (Wenley Moor)
 * High Street, Godalming, Surrey (The town through which the Doctor and Liz Shaw are seen travelling in Bessie at the start of the story)
 * BBC Television Centre, Studio 3, Studio 1, Studio 8

Production errors

 * Quinn arrives in the barn with a wet coat. In the next shot in the same scene, his coat is dry.
 * The vision impairment of the injured Silurian changes between episodes.
 * The "Doctor Who - Jon Pertwee" end credit card "ghosts" throughout Episode 6. Visually it looks similar to screen burn on a plasma television. The cause of this is unknown.
 * When Major Baker is released by the Silurians in order to spread their disease, the rock he gets up from can be seen wobbling.

Continuity

 * This story marks the first appearance of the Silurians. (see Silurians - list of appearances)
 * PROSE: Blood Heat and COMIC: Final Genesis both take place in (separate) alternate timelines which diverge from this story. In both versions, the Third Doctor died, with completely different outcomes for Earth's history.
 * Sea Devils, the Silurian's "aquatic cousins", appear in TV: The Sea Devils.
 * The journalist whom the Brigadier briefly speaks to over the phone at the Wenley Moor nuclear research facility is James Stevens of the Daily Chronicle, who received the number from a . (PROSE: Who Killed Kennedy)
 * After the failure of the Wenley Moor nuclear research facility, among other incidents, was publicised by Stevens in his "Bad Science" series of articles, Harold Wilson's position as Prime Minister of the United Kingdom became untenable and the Labour Party lost the general election in June 1970 to the Conservatives, led by Edward Heath. (PROSE: Who Killed Kennedy)
 * Several weeks after the plague outbreak, Doris Squire was still being treated for shock "after claiming to see some sort of lizard walking upright like a man." According to Stevens, this story did not even make the gutter press. (PROSE: Who Killed Kennedy)
 * Under the pseudonym "Victor Magister", was charged with having caused the plague outbreak, among other incidents, after being captured in Devil's End. Stevens notes that his terrorist activities were little remembered by most British people in 1996. (PROSE: Who Killed Kennedy)
 * By the time of his second incarnation, the Doctor had heard tales of a sentient race which evolved on Earth before humanity but had not yet encountered them at that point in his personal timeline. (PROSE: The Wheel of Ice)
 * Dr. Lawrence and Masters received letters which predicted the exact dates and times of their deaths from the Apocalypse Clock. Lawrence died at 4pm on 21 November. (AUDIO: The Last Post)

DVD releases

 * This story was released as part of a boxset called Beneath the Surface with The Sea Devils and Warriors of the Deep.

Digital releases

 * Released in standard definition in iTunes stores (Australia, Canada, France, Germany, UK and US) as part of the Doctor Who (rather than Doctor Who: The Classic Series) collection Monsters: Silurians, which additionally includes The Hungry Earth and Cold Blood, also in standard definition. (Individual episodes in this collection are titled The Silurians, Episode 1, etc.)
 * On 4 November 2013, this story was released in standard definition in non-UK iTunes stores (Australia, Canada, France, Germany and US) as part of the Doctor Who: The Classic Series collection Doctor Who Sampler: The Third Doctor, which additionally includes Revisited: John Pertwee, The Third Doctor. (Individual episodes in this collection are titled The Silurians, Episode 1, etc.)
 * This story was released in BBC Store, opened for UK residents on 5 November 2015.
 * Was available for streaming in the US through Hulu Plus until early 2016.

VHS releases

 * This was released on video in episodic format in 1993 in the UK and Australia and 1995 in the US.

Editing for both VHS and DVD releases was completed by the Doctor Who Restoration Team.

CD release
The story's soundtrack was released by BBC Audio in January 2008, with linking narration by Caroline John.