The Sensorites (TV story)

The Sensorites was the seventh story of the first season of Doctor Who. Though The Keys of Marinus and The Daleks had both been clear examples of science fictional Doctor Who adventures, neither had specifically stated they were in the relative future of the series. By contrast, The Sensorites was the first story to flatly state a setting in advance of the century of broadcast.

The third episode, "Hidden Danger", had the dubious distinction of being the first episode of Doctor Who delayed because of programming from another BBC department. Just as Series 3 and 4 of the BBC Wales version have featured a one-week gap for the Eurovision Song Contest, The Sensorites was interrupted for special sports programming. (REF: The First Doctor Handbook)

Narratively, certain elements of the story carried on into 21st century Doctor Who. Susan's description of her home planet was almost directly quoted by the Tenth Doctor in Gridlock, and Planet of the Ood suggested a genetic kinship between the Ood and the equally telepathic Sensorites.

Summary
The Doctor, Ian, Barbara and Susan arrive in the TARDIS on board a spaceship. Their initial concern is for the ship's human crew who are suffering from telepathic interference from the Sensorites, but Susan communicates with the Sensorites and finds that the aliens are fearful of an attack from the humans and are just defending themselves. Travelling to the Sense Sphere (the Sensorites' planet) the Doctor then seeks to cure an illness the Sensorites and Ian have succumbed to, but finds that this has been caused by deliberate poisoning. The political manoeuvring of the Sensorite City Administrator adds an additional threat to the TARDIS crew as he seeks to discredit and implicate them.

Strangers in Space (1)
The TARDIS travellers find they have landed on a drifting spaceship and find the crew dead. As they inspect the bodies, they find that they are warm, even though their self-winding watches (which are powered by the movement of the wrist) say they have been dead for at least 24 hours. As the travellers go to leave, one of the crew members, Captain Maitland, regains consciousness and Ian Chesterton helps revive him using a device that he later calls a heart resuscitator. They use this device on the other crew member, Carol Richmond. These two tell the travellers that they are on an exploration mission from 28th century Earth and are orbiting Sense-Sphere. However, its inhabitants, the Sensorites, refuse to let them leave the orbit as they are able to control the brains of any human around them. They say that the Sensorites put them to sleep but never kill them; in fact they regularly feed them.

As they are leaving they do not notice that a mysterious figure is burning the lock out of the TARDIS. As Ian starts to question Maitland on the future of Earth, the Doctor decides that they should leave for fear that Ian learns too much. It is then they discover that the lock is missing which means that the TARDIS is permanently locked.

The Sensorites send the Earth ship on a collision course towards the Sense-Sphere by taking over the minds of the two pilots. The Doctor manages to divert this because he and his travellers seem to be immune from the Sensorites' power. Carol says they have found that different people are affected in different ways. She speaks of another crew member named John who was affected more. When Maitland is questioned about John he says he'd rather not talk about it.

Later that day Barbara and Susan are making food for the rest of the crew and ask Carol where they can find some water. Misunderstanding the directions they go through a sensor operated door. As they go through, an unknown man, seemingly John, locks them in with him inside. John appears to be in a zombie-like state and begins to shuffle towards the frightened girls. However when he finally has them cornered he collapses in front of them and weeps. Barbara consoles him and says that she will make sure he gets better.

Meanwhile on the outside of the door the rest of the crew realise that Barbara and Susan are stuck inside the lock with John. Maitland begins to use a cutting device to get them out. While this is happening Carol confides to Ian that John was to be married to her when they returned to Earth. As the cutting goes on Maitland hears a noise. It is an approaching Sensorite ship. The crew prepare themselves at the controls as the ships roam into sight. Eventually the ship is surrounded and Ian is astounded to see a Sensorite at the window.

The Unwilling Warriors (2)
The Sensorite at the window render Carol and Maitland entirely incapable of movement. Eventually the Doctor awakens Maitland and reminds him of Susan and Barbara trapped on the other side of the door. Maitland continues to cut them out. In the locked area Barbara and Susan are comforting John who is still visibly distressed. He appears to be in semi-constant communication with the Sensorites, who are trying to convince him to scare away the travellers; he refuses to do this as they are his friends now. This act of defiance leaves him crumpled up in pain on the floor.

Two Sensorites have entered the ship. John senses this and informs his new friends. Susan mentions to Barbara that she once visited a planet named Esto on which there lived a species of telepathic plants that screeched if you stood between them, as you affected their thought pattern. With this in mind Barbara and Susan try and overpower the Sensorites thought patterns by both focusing on the phrase, "We Defy You" at the same time. This seems to strongly affect the Sensorites who crumple to the floor.

Ian and the rest of the team manage to open the door and release Barbara, Susan, and the unconscious John. Whilst Ian is putting John to bed he mentions the phrase "the dreams of avarice." Ian shares a theory that John discovered something about the Sense Sphere that would prove valuable to the human race which is why they have trapped the vessel. This is backed up when Maitland states that John was the ship's mineralogist. A quick glance at his findings confirms to the Doctor that the Sense Sphere is rich in molybdenum, a very precious material. As the Doctor makes this discovery the Sensorites mentally attack Carol and Maitland again. Barbara and Ian look for the Sensorites and eventually find them. Barbara runs back to the crew to ask how to lock the doors in an effort to imprison them, whilst Ian slowly backs up, threatening them with a hammer he's found.

Barbara has to wake John to help with locking them out. Barbara notes that they were reasonably passive and never tried to harm Ian. As Barbara and Ian go back to the others to discuss what to do with their prisoners, the Sensorites use a device to cut through the lock. Standing on the other side of the main door the Sensorites talk to Susan telepathically, asking her to ask the others whether they can talk. This is agreed to. They inform the travellers that they have allocated an area of the Sense Sphere where the humans can live in peace but they mustn't leave. The Doctor confronts the aliens and says that he will not live on the Sense Sphere and demands the lock to his TARDIS back. The Sensorites leave to decide what to do. The Doctor notes to his companions that the Sensorites had very heavily dilated eyes in the light which means that in semi-darkness they would be almost blind. It is then that the Sensorites contact Susan again. She appears to be agreeing to something. On being questioned to what she is agreeing to she informs the Doctor that she has agreed to go to live on the Sense Sphere with the Sensorites as they threatened to kill all of the humans otherwise. Two Sensorites take Susan away and the door to the control room closes.

Hidden Danger (3)
The Doctor and his companions refuse to let Susan just leave and chase after her and the Sensorites. They demand that they give her back but the Sensorites argue that they need to take one of their number hostage to ensure the safety of their planet. Susan agrees with the Sensorites, eager to save the lives of her friends. The Doctor shouts at her seeming submissiveness in the face of her kidnapping, which upsets her. When the Doctor tries to grab Susan, the Sensorites get out a weapon. Ian dims the lights which, as the Doctor previously theorised, leaves the Sensorites blinded and terrified and allows the humans to slip away. The Doctor and Susan argue about whether she is adult enough to make her own decisions yet.

Meanwhile the Sensorites have brokered an agreement with Ian whereby Barbara and Maitland remain on the ship while the other humans go down to the Sense Sphere to talk with a Sensorite elder. Ian reluctantly agrees to this but is swayed when the Sensorites say they will be able to cure John on their planet. The Sensorites also share with the humans why they are trapping them in their atmosphere. They recount a story wherein humans visited the Sense Sphere. In their eagerness to leave and inform the rest of their people about the riches of the Sense Sphere they crashed. This crash caused the Sense Sphere to be polluted with a mysterious disease which has been killing large number of the Sensorites ever since. The Doctor promises to see if he can uncover the cause of this mysterious illness. The humans leave for the Sense Sphere.

On the surface of the mysterious planet, three Sensorites are talking. The Elder Sensorite is justifying his decison to the others saying that the risk he is taking on inviting the humans into his palace will be rewarded if the Doctor can cure the Sensorites of the disease. The other two seem dismissive of the human race saying that they are lesser beings and loud and ugly and should have been met in the mouintains. Eventually the two other Sensorites act subservient to the Elder's face but as soon as he leaves they doubt his leadership. The most vocal Sensorite in this uprising is a Sensorite known as the Administrator. He informs the other Sensorite that he is so distrustful of the humans that he has aimed a device called the disintegrator at the room where the humans are to meet the Elder in order to preserve the Sense Sphere's purity.

When the humans are welcomed into the court of the Elder, John and Carol are taken away to be cured, while the Doctor, Ian, and Susan are ushered in for a meeting with the Elder. While this is going on the administrator is setting the coordinates for the humans' destruction. Just as he is about to shoot, a Sensorite comes in and orders the Administrator to stop, saying that the humans are harmless and are only there to help. The Administrator reluctantly complies, but he also further doubts the Elders capabilities and discusses a potential uprising with his friend.

Back in the court the humans are given food and water. The Elder shouts at a Sensorite servant, incredulous as to why his guests have not been given the same food and water as he has. He sends the water back with the Sensorite ensuring that he return with the Crystal Water of which he drinks. However, Ian has already drunk his. The Elder explains the rigid hierarchy of the Sense Sphere. Elders such as he wear two sashes, other controllers wear one, while the populace are content with no sash. The Doctor asks what is the difference as you rise up the social order. The elder states that the higher up you get the better your quality of life and the better food and drink you get. The Doctor asks if any of the elders fall foul of the disease. The elder responds in the negative. All through this conversation Ian has been coughing and choking. On being asked what is wrong, he says his throat is burning up, and asks for some water. Before he can answer he falls to the floor unconscious. The Elder informs the Doctor that this is the first sign of the illness and Ian is dying.

A Race Against Death (4)
The Doctor and Susan try to figure out what it is that may have caused Ian's collapse. They suspect that it may have been the water as that is they only thing that Ian experienced that they did not. He suspects that the disease of which the Sensorites speak isn't a disease but a poisoning. Meanwhile two elders discuss whether Ian's collapse is a subterfuge on the Doctor's part to gain the trust of the Sensorites, seemingly to cure him and then regain the TARDIS. They decide that they should allow the Doctor to try to cure the poisoning.

This news does not go down well with the Administrator, who orders the scientists to murder John, whose mind they are trying to erase. He is berated by an elder saying that his constant belligerence will get him into trouble. The Administrator tells the scientist that the Doctor is evil and is trying to gain the trust of the Sensorites only to betray them. John, half conscious, seems to agree with this by saying, "Evil." The Administrator convinces the scientist that this is the human admitting and tells him to pass it on to the elders. When the scientists leave John tells the Administrator that he meant that there is evil in the Sensorites. The Administrator says that he knew that all along and does not care for what humans think as his only wish is to wipe them from existence. On hearing the Administrator's theory the elders decide to not allow the Doctor his TARDIS in order to conduct experiments on the water and instead allow him access to their own laboratory. This upsets the Doctor who shouts at them, which clearly causes them pain. Eventually he reluctantly agrees.

The Administrator talks to another Sensorite about how to claim back the key to the disintegrator. He says that the only way that Sensorites tell each other apart is by their sashes. He says that if he were to disguise himself as an elder he could gain it back. The Doctor briefs the scientists on what he is looking for. He suspects that the water supply has traces of atropine poision in it. The scientists tell him that their are 10 different areas from which the water is gathered. He asks them to fetch samples for him in order to test them all. When they do, it is discovered that it is only Area 8 that possess traces of Atopine poison. The Doctor prepares an antidote for this affliction.

Meanwhile the Administrator kidnaps an Elder and his family. Taking off his sash he says that he will use this disguise to prove to the Elder that the Doctor is evil and does not intend to help them at all. He suspects that the antidote that the Doctor has made is actually a poison. He believes Ian has been play acting at being ill and that he will pretend to get better. When he does this the poison will be diseminated to the Sensorites which will wipe them out, leaving the humans to harvest the Sense Sphere. The Administrator soon proves that this is an effective plan when he encounters a scientist who thinks him to be the Elder. He tells him to give him the antidote as he would like to give it to Ian. As soon as the scientist is out of sight he smashes the test tube on the floor. This way if Ian gets better regardless he will know that the Doctor has been lying, but if he dies then the Doctor will be proved true.

A scientist escorts the Doctor down to the aquaduct for the Doctor to experiment on the source of the poison. The scientist says that they can never stay down there too long as it is dark and for one reason or another their plans to light it are always scuppered. When the Doctor tells the scientist that he plans to enter the aquaduct the scientist balks and warns him that there are monsters inside. The Doctor questions whether they have ever seen the monster and the scientist says that they have only heard his roar. The Doctor disimisses the scientist but speculates how convenient it is that the aquaduct is both dark and noisy, two things the Sensorites cannot tolerate. The scientist returns to the Elder and tells him that the Doctor has gone into the aquaduct. The Elder is disgusted saying that the aquaduct is death to anyone that enters. Hearing this Ian and Susan go to rescue him. The Elder, impressed with the humans' love for each other, telepathically tells his fellow Elder that they are mistaken and that the humans are noble people. This message is picked up by the Administrator who is disgusted with the Elder's weakness but delighted that the humans are heading to their death in the aquaduct.

Ian and Susan reach the mouth of the aquaduct. The scientist gives them a radio electric light. Ian seems to be getting weaker but still enters. Deep inside the dark aquaduct the Doctor seems to have found what he suspected he would - Deadly Nightshade. As he does however a terrifying roar echoes through the tunnel.

Kidnap (5)
The Doctor looks up in terror at the unseen figure before him. Ian and Susan hear this noise and a scream from the Doctor and run towards where the sound came from. They find the Doctor prostate on the floor, rumpled but unharmed. The only damage done to him is a ripping of his jacket. Once out of the aquaduct the Doctor shares his theory that a Sensorite is plotting against them and that the beast in the aquaduct is the thing that is poisoning the water supply. Unluckily for the travellers they have been overheard by a Sensorite loyal to the Administrator.

Meanwhile back at the police Carol speaks to the Sensorites about John, wondering why it is that their interference with her lover has made him so ill. The scientist explains that the Sensorite brain is always open and is always receiving information. In the case of John's mind it has opened the fear compartment of his brain and is constantly rendering him terrified. She also wonders why he constantly speaks of treason and betrayal. The scientist explains that it must be delusional as Sensorite society is built on trust and respect for others.

The Sensorite spy reports to the Administrator that the Doctor is on to his plot. The Administrator demands that the Second Elder contact the Chief Warrior in order for him to hand over the key to the disintegrator. This the elder begrudingly does. The Administrator goes to pick up the key in the courtyard.

As the Doctor, Ian, and Susan return to the Palace they decide that they should ask if Barbara could join them on the Sense Sphere. At this point they encounter the Administrator in the guise of the Elder as he takes the key from the Chief Warrior. The Doctor pursues him to ask if Barbara could be brought to the Sense Sphere but the Administrator runs off.

When the Administrator returns to the disintegrator room he begins to set up the weapon. However the Second Elder overpowers the Sensorite helper and snatches the key from the Administrator and bends it. By this time the helper has composed himself and kills the Elder. The helper is concerned that this will expose them but the Administrator says that he can work this to their advantage. He asks if the Chief Warrior can describe how the Doctor looks. In receiving an answer to the affirmitive he takes them to the palace.

The Chief Elder receives the Doctor and his friends, his kindness underlined by the fact he gives the Doctor a cloak to replace his coat. The Doctor lays down his plan in helping purify the water supply. He intends to go back into the aquaduct and slay the monster that lies within. This discussion is interrupted by the Administrator who tells the Chief Elder that the Second Elder has been killed. The Chief Warrior says that he saw the Doctor kill him over a fight about the disintegrator key. The Chief Elder asks if it was sure that it was the Doctor, and the Chief Warrior says that he could tell by his distinctive hair and the fact that he could clearly see that the Doctor took the weapon out of his coat. Ian cross examines the Chief Warrior making sure that he reasserts that he saw the Doctor's coat. At this point the Doctor stands and reveals he is wearing a cloak. The Chief Warrior tries to change his tune but the Chief Elder sends him to prison. The Administrator apologises to the Elder for bothering him. The Elder states he was doing exactly what he ought to. The Administrator gives the Elder the sash of the Second Elder and says that he should now pick his replacement. The Doctor, seeing an opportunity to befriend another Sensorite, suggests the Admistrator. The Elder agrees and gives the sash to the Administrator. He shows no thanks to the humans.

Meanwhile John is entirely healed and reunited with Carol. He also recognises Susan. When Susan asks what he was referring to when he spoke of betrayal he says that he can't quite remember but is sure that a Sensorite is plotting against the humans but is unsure which one. The Administrator pounces on this and asks whether the treacherous Sensorite is in the room. John says he is not. The Administrator leaves and John says that the only thing he remembers about the Sensorite is that their was something odd with his uniform. In another part of the lab the Doctor has discovered an old map of the aquaduct which he asks the scientist to improve and bring to him in order for him and Ian to have a working map for their expedition. At this time John remembers that the strange thing about the Sensorite that is treacherous is that he had a collar. The Doctor is distraught to realise that it is the Administrator that is evil.

Meanwhile the Administrator has sprung the Chief Warrior out of prison and is asking another favour of him. He asks if he can render the weapons that are going to be given to the Doctor and Ian netural. The Chief Warrior says that that is easily done. He also intercepts the map of the aquaduct and corrupts it so that the explorers will get lost.

Ian and the Doctor are given the false information and the ineffective weapons by the Chief Elder and ask if Barbara might be allowed to come to the Sense Sphere to look after Susan. The Chief Elder agrees with this. Ian and the Doctor decide to not tell Susan that they are going as she would only demand to come with them and as Barbara will soon join her it would not be worth it. They leave for the aquaduct.

Carol, John, and Susan, oblivious to the Doctor and Ian's journey, are preparing a meal for when the other humans return. After a long period of waiting Carol goes to look for them. As she crosses the courtyard a hand grabs her and pulls her away.

A Desperate Venture (6)
Carol is brought into the disintegrator room and is foced to write a letter to John and Susan saying that she has gone up to the space ship. Little does the Administrator know that Barbara has just been brought down from the ship and can prove that Carol was not there. When the letter is received by the humans they become even more suspicious of the Sensorites around them. They show the letter to the Chief Elder who says that the letter is obviously falsified. They also suspect something has happened to the Doctor and Ian but the Chief Elder says that they have gone into the aquaducts and did not want to worry their friends. Susan points out that the ink on the letter is still wet, meaning that Carol must be being held very close. They ask the Chief Elder where they could be. He suggests the disintegrator room. John goes to investigate and sneaks in as Carol is being threatened with the disintegrator by the Chief Warrior. While he is distracted by John, Carol unarms him and the Chief Warrior is yet again imprisoned.

In the palace the Administrator is talking to the Chief Elder offering consternation as to how the Chief Warrior escaped and expecting him to serve a long sentence in prison. He is also very concerned as to whether the Chief Warrior has implicated anyone else.

Meanwhile in the aquaduct the Doctor and Ian discover something moving ahead of them. As Ian edges forwards to investigate a human attacks them. A scuffle ensues and the man escapes. All that is left is a badge in the shape of a rocket ship.

Back at the palace it is decided that, due to the fact that the Doctor's weapons and maps are faulty, another party should enter the aquaduct in order to rescue them. It is decided that Barbara and John will go in whilst Susan will stay behind and guide them using her ability to transmit her thoughts to the Sensorites - for this Barbara borrows one of the Sensorites tools for communication.

Back in the aquaduct the Doctor and Ian are in pursuit of the humans but are soon surrounded by them. They take charge of the two men and take them to their Commander. They seem wild and unhinged. The Doctor suggests that these are the men left over from the last expedition to the Sense Sphere. They are keen to know if the men are alone and they promise that they are. As they are taken deeper into the aquaduct to meet the Commander, the Doctor surreptitiously makes marks with chalk in order to find their way back if they need to escape. However, Barbara and John take this to be a signal for them to follow them.

When the two men meet the Commander he reveals to them that they were indeed the survivors of the first expedition. The ship that crashed all those years ago were deserters from this militia. The Commander was forced to blow up the ship before they escaped from the army. His group has also been the ones poisoning the Sensorites in order to completely wipe them out and harvest their planet. He seems to be under the illusion that his men are at war with the Sensorites. At this point one of the men comes in reporting that there are more people coming. This angers the Commander who believes that the Doctor has lied to them. When Barbara and John turn up, the Doctor convinces the men that they are a victory party celebrating the glorious success of the humans in the war. They make way to the exit of the Aquaduct. Surreptitiously Barbara contacts the Sensorites to position themselves at the mouth of the aquaduct with their weapons., where they seize the humans.

The next scene is in the TARDIS, after the Sensorites have presumably returned the lock to the Doctor. The travellers are watching Carol, John, and Maitland disappear off into space. Ian makes a comment stating that at least the spacemen know where they are going. This angers the Doctor who says that wherever they land next he is leaving Ian there.

Cast

 * The Doctor - William Hartnell
 * Ian Chesterton - William Russell
 * Barbara Wright - Jacqueline Hill
 * Susan Foreman - Carole Ann Ford
 * John - Stephen Dartnell
 * Carol Richmond - Ilona Rodgers
 * Captain Maitland - Lorne Cossette
 * First Sensorite - Ken Tyllsen
 * Second Sensorite - Joe Greig
 * Third Sensorite - Peter Glaze
 * Fourth Sensorite - Arthur Newall
 * First Elder - Eric Francis
 * Second Elder - Bartlett Mullins
 * First Scientist - Ken Tyllsen
 * Second Scientist - Joe Greig
 * Warrior - Joe Greig
 * Commander - John Bailey
 * First Human - Martyn Huntley
 * Second Human - Giles Phibbs
 * Sensorite - Anthony Rogers (uncredited)
 * Sensorite - Gerry Martin (uncredited)

Crew

 * Writer - Peter R. Newman
 * Director - Mervyn Pinfield (episodes 1-4), Frank Cox (episodes 5-6)
 * Producer - Verity Lambert
 * Script Editor - David Whitaker
 * Designer - Raymond Cusick
 * Assistant Floor Manager - Dawn Robertson
 * Assistant Floor Manager - Val McCrimmon
 * Associate Producer - Mervyn Pinfield
 * Costumes - Daphne Dare
 * Incidental Music - Norman Kay
 * Make-Up - Jill Summers
 * Make-Up - Sonia Markham
 * Production Assistant - David Conroy
 * Special Sound - Brian Hodgson
 * Studio Lighting - Peter Murray
 * Studio Sound - Jack Brummitt
 * Studio Sound - Les Wilkins
 * Theme Arrangement - Delia Derbyshire
 * Title Music - Ron Grainer

Story notes

 * All episodes exist in 16mm telerecordings.
 * Negative film prints of all episodes were recovered from BBC Enterprises in 1978.
 * Jacqueline Hill does not appear in episodes 4 and 5 as she was on holiday while they were filmed.
 * This story was nearly cancelled as a result of a studio dispute.
 * Hidden Danger (Episode 4) was postponed for one week due the BBC's sports programme Grandstand being extended on 4 July 1964, Hidden Danger was therefore postponed and shown the following week.
 * Stephen Dartnell, who appears as John, had previously appeared as Yartek in The Keys of Marinus.
 * John Bailey, later to feature as Edward Waterfield in 1967's The Evil of the Daleks, has a role here as the Commander.
 * Designer Raymond Cusick used almost all curves in his sets for the Sense Sphere, feeling that this would give a more alien look.
 * Russell T Davies has acknowledged the Sensorites as an influence on the basic concept of the Ood in The Impossible Planet and The Satan Pit. Computer readouts (and a mention by Davies in an episode commentary) revealed that the Ood sphere and Sense Sphere are part of the same star system.
 * For decades, Who fandom was unable to discover much about the story's writer, Peter R. Newman. It was not until production of supplementary features for the 2012 DVD release that facts such as his exact dates of birth and death and his general biography became known (DOC: Looking for Peter).

Ratings

 * Strangers in Space - 7.9 million viewers
 * The Unwilling Warriors - 6.9 million viewers
 * Hidden Danger - 7.4 million viewers
 * A Race Against Death - 5.5 million viewers
 * Kidnap - 6.9 million viewers
 * A Desperate Venture - 6.9 million viewers

Myths

 * The Humans responsible for poisoning the water supplies were part of a group called INEER. (The letters INEER on the badge Ian rips from the man's uniform are clearly the end of the word 'Engineer'.).
 * Arthur Newall appeared in Doctor Who as a Dalek. (He in fact appeared in this story as a Sensorite.)

Filming locations

 * BBC Television Centre Studio (TC3)
 * Lime Grove Studios (Studio D)

Production errors

 * During episode 1 while the Doctor is delivering his lines the camera hits the table in front of him.
 * The drill marks are visible before Maitland starts to use the drill.
 * In some scenes, the walls are visibly unstable.
 * The Doctor calls Maitland "John" in episode 1.
 * When Ian sees the Sensorite in space at the end of episode 1, its hands are pressed against the window, but at the start of episode 2 its hands are not pressed on the window.
 * The note Carol is forced to write and hands to the City Administrator is different to the one Barbara is reading in the next scene.
 * A woman's voice reciting numbers can be heard in the background of one scene in which Susan speaks with a Sensorite. The DVD release explains this was audio of a production assistant calling out camera shots which somehow was overheard by the studio microphones (possibly from an unattended set of live headphones in the studio).
 * In episode 1, the Doctor and Maitland react to a sound effect that isn't actually heard.

Continuity

 * The Doctor and his companions, in episode one, all talk about how a simple trip turned into one big adventure (A paraphrase of "it all started as a mild curiosity in a junkyard" from The Pilot Episode). They then recount the events of An Unearthly Child, The Daleks, Marco Polo, The Keys of Marinus and The Aztecs.
 * In his tenth incarnation, the Doctor visited the Ood Sphere, located in the same star system as the Sense Sphere.
 * The Doctor first mentions his dislike of weapons, which is very prominent in the newer series.
 * Susan mentions Quinnis, a location later featured in a Companion Chronicles storyline.

Timeline
Carol Richmond states that the story takes place in the 28th century.

Timeline

 * This story occurs after ST: The Reign Makers
 * This story occurs before CC: The Transit of Venus

Novelisation and its audiobook

 * Main article: The Sensorites (novelisation)


 * The story novelisation was published as Doctor Who: The Sensorites in July 1987 ISBN 0-426-20295-3. The story was written by Nigel Robinson and was number 118 in the series of 156 Doctor Who novels published by Target Books.

DVD, video and audio releases

 * Video Release - Released as Doctor Who: The Sensorites


 * UK Release: June 2000 / US Release: October 2003
 * PAL - BBC Video BBCV7276
 * NTSC - Warner Video E1852


 * Released as part of The First Doctor Collection boxset in the UK - BBCV7278.


 * Released as part of The End of the Universe Collection in the US.


 * The Sensorites was released by BBC Audio in July 2008, with linking narration by William Russell.


 * Editing for VHS release completed by Doctor Who Restoration Team


 * DVD release occurred in the UK on 23 January 2012, followed by North American release on 14 February. As with most releases from this era, the episodes have been reprocessed digitally to simulate the original videotaped look of the original broadcasts.

Special features:
 * Looking for Peter (21 min.): documentary hosted by Toby Hadoke in which he and researcher Richard Bignall attempt to learn more about the enigmatic writer of The Sensorites, Peter R. Newman.
 * Vision On (7 min.): Clive Doig discusses the role of the vision mixer in making early Doctor Who episodes, including footage and discussion of studio mishaps that occurred on screen.
 * Secret Voices of the Sense-Sphere (2 min.): a companion piece to Vision On. Doig explains the origin of a mysterious female voice heard reciting numbers in the background of one scene.
 * Audio commentary by William Russell, Carole Ann Ford, Joe Greig, Martyn Huntley, Giles Phibbs, Frank Cox, Raymond Cusick, and Sonia Markham (makeup artist). Moderator: Toby Hadoke
 * PDF materials: Radio Times listings and original design drawings
 * Photo gallery (4 min.)
 * Production notes subtitles
 * Trailer for the Revisitations 3 box set