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Mawdryn Undead was the third serial of season 20 of Doctor Who. It saw the return of the Brigadier, and was the first story in the "Black Guardian trilogy". It also marked the first appearance of Vislor Turlough as both a companion and a villain.

Due to its use of very specific date, such as placing the Brigadier's retirement during 1976, this story attempted to address the so-called UNIT dating controversy. However, in so doing, it became a major part of that very controversy.


Turlough may look a normal pupil at a boys' boarding school, but he’s actually an alien from another planet. And when the menacing Black Guardian asks him to kill the Doctor in return for a trip home, the boy quickly agrees.

By coincidence, Turlough's maths teacher is an old friend of the Time Lord's. But why doesn’t the Brigadier remember that? The Doctor, along with his friends Tegan and Nyssa, is about to find out…


Part one[]

In 1983, the former UNIT Brigadier Alistair Gordon Lethbridge-Stewart teaches mathematics at Brendon Public School for Boys. A mischievous student, Turlough, convinces his classmate Ibbotson to join him in a joyride in the Brigadier's priceless antique car, which they accidentally veer off the road and crash. While unconscious, Turlough is contacted by the sinister Black Guardian. The Black Guardian knows Turlough is actually from another planet. He offers Turlough transportation off Earth if he will kill the Guardian's greatest enemy: the Doctor.

At the same time, the Fifth Doctor, Tegan and Nyssa have problems of their own. As Tegan attempts to get reassurance from the Doctor that she is free from the Mara, the TARDIS is caught in a warp ellipse and materialises on board an apparently empty starliner locked in a perpetual orbit in time and space. Turlough, on the Black Guardian's instructions, transports himself onto the liner by means of a transmat capsule and encounters the TARDIS crew. The Doctor travels to Earth via transmat, taking Turlough with him, to get rid of the transmat interference trapping the TARDIS on the liner. The source of the interference is not far from the school grounds. As the Doctor is sorting out the device, Turlough, responding to the Black Guardian's exhortations, picks up a large rock and prepares to bring it down on the back of the Doctor's head...

Part two[]

Mawdryn regenerating

"The Doctor" regenerating.

The interference device explodes, knocking the Doctor backwards and forcing the rock out of Turlough's hands. The TARDIS materialises nearby, but vanishes shortly after, seemingly leaving the Doctor stranded. The Doctor meets the Brigadier at the school, but is puzzled when his old comrade-in-arms does not remember him. He eventually works around the apparent gap in the Brigadier's memory by mentioning Jo Grant, Liz Shaw and other past adventures. To the Doctor's surprise, the Brigadier claims to remember Tegan, having met her shortly before his nervous breakdown in 1977. The Doctor realises that the TARDIS hasn't disappeared; the destruction of the device knocked the TARDIS off a time track and sent it back six years.

In 1977, Tegan and Nyssa encounter the transmat capsule. Inside is an alien-looking humanoid whom they initially believe is the Doctor, horribly injured; they bring the figure back to the TARDIS and make him comfortable on the control room floor with blankets and the burgundy greatcoat worn by the previous Doctor. Tegan goes to the school for help, where she meets the younger Brigadier, who accompanies her back to the TARDIS, where Nyssa tells them "the Doctor" is regenerating. The three enter the TARDIS control room. The figure, who is a scientist called Mawdryn, now wearing the Doctor's coat, turns to face them. The top of his skull is missing, revealing his pulsing brain. Nyssa screams in horror.

Part three[]

Black Guardian on Mawdryn's ship

"There is nothing to fear. Reach out your hand."

Under the pretence of being the Doctor, suffering a failed regeneration, Mawdryn convinces the others to bring the TARDIS to the ship, claiming it has restorative capabilities. Meanwhile, the Doctor, Turlough and the present-day Brigadier use a TARDIS homing device on the damaged transmat to bring themselves to the ship, splitting up soon after to search for Tegan and Nyssa. Under the Black Guardian's instruction, Turlough opens a secret room, revealing several humanoids suffering from the same malady as Mawdryn. Mawdryn fools the present-day Brigadier into using a stolen Time Lord device to stabilise his condition. Finding the TARDIS, the Doctor reunites with Tegan and Nyssa. When he learns there are two Brigadiers aboard, he has to try to keep them apart lest the resulting energy discharge prove catastrophic.

The Doctor and Nyssa meet with the present-day Brigadier and Mawdryn. Mawdryn reveals his fellow scientists and he tried to steal the secret of regeneration from the Time Lords, but caused perpetual mutations, leaving them practically immortal but in horrible agony. Tegan is chased into the room by Mawdryn's mutated crewmates. The mutants take their places in the regeneration room and Mawdryn pleads with the Doctor to help them die by giving them his regeneration energy. The Doctor refuses, explaining to Tegan that if he did so it would mean the end of him as a Time Lord...

Part four[]

Black Guardian on the TARDIS screen

"They are harmless, except to the Doctor."

The Doctor explains that he can only regenerate twelve times, and that, as he has already done so four times, helping the mutants die would consume all eight of his remaining regenerations. Although Mawdryn proclaims that the only thing they desire is their deaths rather than the Doctor's 'murder,' the Doctor refuses, unwilling to sacrifice his remaining lives to save them from their own mistake.

Under the Black Guardian's orders, Turlough locates the Brigadier of 1977 and locks him in a side room to keep the two Brigadiers from touching.

Trying to leave in the TARDIS, the Doctor discovers that Tegan and Nyssa have been infected by the same malady as Mawdryn and his compatriots. Attempted time travel accelerates their conditions and reversing out of the warp ellipse only regresses Tegan and Nyssa into children. The only cure, it seems, is to do what Mawdryn demands; the Doctor must give up his remaining regenerations. Meanwhile, the past Brigadier escapes the room and encounters Mawdryn and his crew. Fearing the time imbalance, they send him into the transmat. Unbeknownst to them, the transmat cannot make the trip while the TARDIS is on the vessel and the capsule returns to its station seconds later.

Mawdryn's ship explodes

Mawdryn's ship explodes.

Hooking himself up to Mawdryn's apparatus, the Doctor is about to sacrifice himself when the two Brigadiers meet and touch hands, causing a discharge of temporal energy at precisely the right instant to act as a substitute power source. Tegan and Nyssa are cured, the alien scientists end their undead existence and the Doctor remains a Time Lord. The younger Brigadier, however, will not remember his time with the Doctor until they meet again in 1983. The Doctor, Nyssa and Tegan deliver the 1977 and 1983 versions of the Brigadier back to their respective times. Turlough is in the TARDIS control room when they return. He asks if he can join them and the Doctor comments that he already has. In space, Mawdryn's ship self-destructs.


Uncredited cast[]



Anatomy and physiology[]

  • Tegan, Nyssa, and the Brigadier refer to having seen the Doctor regenerate.

Cultural references from the real world[]





Theories and concepts[]

Transport technology[]

  • Tegan knows a great deal about transmats.
  • Mawdryn and his people make use of transmat capsules.
  • Tegan compares the spacecraft to the ships Queen Mary, about its luxury and Mary Celeste, about its desolation.
  • The Brigadier's car is a blue 1929 Humber 16/50 open tourer, Imperial model.


  • The Brigadier, oblivious of the Doctor, asks him if he had signed an Official Secrets Act to keep secret his involvement with UNIT.

Story notes[]

  • Every story during Season 20 included a story element from the Doctor's past. For this four-part story, one such element was the Black Guardian, who last faced the fourth incarnation of the Doctor at the conclusion of the Key to Time saga in 1979. Another, of course, was the Brigadier.
  • The original intent of the production team was for the character of Ian Chesterton, one of the original regulars from the series' first two seasons from 1963-65, to return for a guest appearance in this story, hence the school setting; Chesterton was a science teacher. However, actor William Russell proved to be unavailable due to a stage commitment. Some consideration was given to using Harry Sullivan, who was a regular in the programme for a season in the mid-1970s, before the return of Lethbridge-Stewart was eventually decided upon.
  • The Radio Times programme listing for part one was accompanied by a black-and-white photograph of the Doctor seated in the Brigadier's school quarters with the accompanying caption "More time travel problems for the Doctor (Peter Davison) result in a reunion with old 'friends': 6.50". (original published text)
  • Radio Times credits Nicholas Courtney as "Brigadier Lethbridge-Stewart" in the combined cast for parts one/two, and as "Brigadier" in the combined cast for parts three/four. All on-screen credits read "The Brigadier".
  • During the scene in part four where the Doctor's companions are regressed to children, the young Nyssa and Tegan were played by Lucy Baker and Sian Pattenden respectively — both of whom were uncredited on-screen and in Radio Times despite having the respective dialogue "It's no good, Doctor!" and "Stop! Stop!"
  • Former producer Graham Williams, the creator of the Guardians, did not know about their return in this season and learned about it only years later during an on-stage interview at a Doctor Who convention.
  • Originally the slot that this story occupies was to have been given to the long-delayed "The Song of the Space Whale" (or Space Whale), in which Turlough would have been one of a group of colonists. However, this was again cancelled and this story took its place. Since it would now serve to introduce Turlough rather than include him as an established character, his role was merged with one of the schoolboys.
  • Peter Grimwade's previous story, TV: Time-Flight, also takes place in two different time zones.
  • Peter Grimwade based the public school setting on his own upbringing. He was an alumnus of Truro School, an all-boys private establishment in Cornwall and he "knew the background of a dreadful minor public school very well".
  • The script suggests that the Doctor takes Turlough on because he misses Adric.
  • Nicholas Courtney later revealed that he was baffled by the script.
  • Turlough's headmaster was originally called Mr Sellick.
  • Ian Levine pointed out that setting part of the story in 1977 would now break with the continuity of the Brigadier's original serials, but was overruled.
  • Peter Davison thought there were an awful lot of holes in the plot and was amazed that the audience didn't notice. He claimed that it taught him a lesson about plots in general.
  • Mark Strickson claimed that the communication crystal was attached to a car battery to make it bright enough to be seen on camera and each scene with it had to be fourteen seconds long otherwise it got too hot to hold.
  • Peter Davison and Nicholas Courtney previously appeared in the All Creatures Great and Small episode "Matters of Life and Death".
  • Peter Grimwade originally wanted the events of the story to take place several centuries apart, but he was encouraged to bring them closer together so that one character could be present in both time periods.
  • The title was derived from the Welsh words marw (“dead”) and dyn (“man”).
  • David Collings was cast as Mawdryn due to his resemblance to Peter Davison.
  • Peter Grimwade included the flashback scene based on the success of similar scenes in Logopolis and Earthshock, both of which he directed.
  • Make-up designer Sheelagh Wells had been disappointed with the way Mawdryn's brain protuberance blended with his skin and so, during the intervening fortnight, costume designer Amy Roberts hid the join by adding a metal headband to the mutants' outfits.


  • Part one - 6.5 million viewers
  • Part two - 7.5 million viewers
  • Part three - 7.4 million viewers
  • Part four - 7.7 million viewers

Filming locations[]

Production errors[]

If you'd like to talk about narrative problems with this story — like plot holes and things that seem to contradict other stories — please go to this episode's discontinuity discussion.
  • In the scene in which Turlough crashes the Brigadier's car, when he closes in on the other car, the next shot shows the car on the other side of the road, then the next shot shows the car on the right side of the road.
  • In the same scene, both sides of the road are covered in thick bush, but as the car is about to crash, an open gate suddenly appears.
  • While both aspects of the Brigadier are walking the same stretch of corridor in Mawdryn's ship, a split-screen effect is used to have them both present, then faded out so that one of them can cross the full length of the set. Unfortunately, the fade is obvious in the finished programme as one half of the scene clearly shifts in tone.


  • The flashback montage when the Brigadier recovers his memory commits a continuity error by including a Krynoid, an enemy the Brigadier never encountered. The montage actually depicts an Axon, which the Brigadier did encounter. This confusion is likely the result of the first-stage Krynoid re-using an Axon costume that was sprayed green, and the montage using a sepia tint which makes the Axon look darker and more like a Krynoid.


Home video and audio releases[]

DVD releases[]

This story was released as Doctor Who: Mawdryn Undead.


Special Features[]

  • Commentary by Peter Davison (the Doctor), Mark Strickson (Turlough), Nicholas Courtney (The Brigadier), and Script Editor Eric Saward.
  • Who Wants to Live Forever? - Cast and crew look back at the making of this story
  • Liberty Hall - A new drama in which a journalist travels to Brendon School to interview Brigadier Lethbridge-Stewart
  • Deleted and Extended Scenes
  • Film Trims - Taken from the location filming, including clapperboards and cast and crew setting up and performing various scenes
  • Out-takes
  • New CGI effects - The option to watch the story with many of the original video effects sequences replaced by new CGI
  • Continuity - Original BBC-1 continuity announcements
  • Studio floorplans (DVD-ROM - PC/Mac)
  • CGI Storyboards (DVD-ROM - PC/Mac)
  • Radio Times Listings (DVD-ROM - PC/Mac)
  • Isolated Music Score
  • Production Information Subtitles
  • Photo Gallery
  • Coming Soon Trailer - The Twin Dilemma
  • Easter Eggs:
    • TARDIS Information File. To access this hidden feature, press left at Deleted and Extended Scenes on the Special Features menu to reveal a hidden Doctor Who logo.
    • ​Studio floorplans. To access this hidden feature, press left at Set Photo Gallery on the Special Features menu to reveal a hidden Doctor Who logo.


Box set[]

Video releases[]

This story was released on VHS in November 1992 in the UK markets, 1993 in Australian markets and 1994 in US markets.

External links[]