Logopolis was the final story of Season 18 of Doctor Who.It was Tom Baker's last story as the Doctor and marks the first appearance of Peter Davison in the role, at the very end of the story. This serial also marks the first appearance of Janet Fielding as new companion Tegan Jovanka.
The Doctor goes to Logopolis to repair the TARDIS's chameleon circuit, but his old enemy the Master has plans of his own for the planet of mathematicians, a plan that could spell doom for the universe.
The Doctor is pacing around in the TARDIS Cloister Room, pondering thoughts of decay and entropy. As he and Adric prepare to leave, the large bell in the centre of the room begins to ring. This worries the Doctor, as the sound of the Cloister Bell is a sign of impending universal catastrophe.
To keep his mind off this, he decides to repair the TARDIS's chameleon circuit, which has frozen it into the shape of a police box. In order to do this, he intends to materialise the TARDIS around a real police box (thus disguising it), and then obtain its precise measurements in 27 dimensions. With these measurements, he will have the inhabitants of the planet Logopolis produce a mathematical calculation — a Block Transfer Computation — to reset the circuit. However, the "police box" he materialises around is actually the TARDIS of the Master, who has survived their encounter on the planet Traken. When the Doctor materialises around the Master's TARDIS, a recursive loop of TARDISes within TARDISes is formed.
Meanwhile, an airline stewardess, Tegan Jovanka, is being driven to the airport by her Aunt Vanessa. After their car breaks down, Tegan decides to go to the "police box" for help, but finds herself lost in the TARDIS instead. The Doctor and Adric enter another police box in a duplicate TARDIS, but the Doctor, telling Adric to wait behind finds himself this time outside the box. He meets a number of policemen, who find the shrunken, dead bodies of Tegan's aunt and another policeman.
The police think the Doctor has something to do with it, but Adric creates a distraction, and allows the Doctor to escape. In the distance, a mysterious white-clad stranger watches the proceedings. Realising that the shrunken bodies are the trademark of the Master, the Doctor decides to materialise the TARDIS underwater, to literally flush him out. The Doctor misses the River Thames, however, and lands on a boat instead. The mysterious stranger appears here too, and beckons to the Doctor, telling him to go to Logopolis.
As the TARDIS arrives at Logopolis, Tegan finds her way to the control room, somewhat annoyed. She asks to know where her aunt is, and the Doctor, realising that Tegan's aunt was the dead woman in the car, skirts the question. Once they exit the TARDIS, the Doctor asks the Logopolitan leader, the Monitor, for his help. The Logopolitans are able to model reality by pure mathematics — whatever they calculate can take physical form. Since block transfer computations cannot be calculated by machines or computers, the Logopolitans speak aloud a line of calculations and passing them on.
However, unknown to the group, the Master has arrived on Logopolis, and has killed several Logopolitans, which disrupts the calculations for the TARDIS. When the Logopolitans produce the required computation and the Doctor attempts to enter it into the TARDIS, it instead shrinks the TARDIS to half its normal size and causes strange effects inside the ship.
The Logopolitans try to stabilise the TARDIS using sonic projectors to project a stasis field while the Monitor and Adric attempt to uncover the fault. Meanwhile, Nyssa has been brought from Traken by the Watcher, the mysterious white figure the Doctor spoke with. She is searching for her father. The Monitor and Adric work through the city and discover the shrunken bodies of three Logopolitans. Correcting the error this has caused, they bring the new computation to the TARDIS. Tegan holds the notes up to the TARDIS so the Doctor is able to read them through the scanner and correct the fault. The Doctor emerges from the now restored TARDIS, and admits to Tegan that her aunt is dead. Meanwhile, Nyssa finds the Master, whom she believes to be her father as he is inhabiting Tremas's body. The Master gives her a bracelet, which is actually a device which will allow him to control her actions.
The Master attaches a device to the sonic projectors and sets up a counterwave that brings silence to the Central Registry, preventing the Registers from making their calculations. He then goes to the Registry's control room (a replica of the Pharos Project on Earth, a radio telescope tasked to seek out signs of extraterrestrial life), and demands that the Monitor tell him what the true purpose of Logopolis is. The Doctor arrives with Adric and Nyssa, and Adric deactivates the Master's device, only for the Master to have Nyssa attempt to throttle him. Tegan restores the device, and the Master repeats his demand. The Monitor warns the Master that bringing Logopolis to a halt will cause universal disaster, but the Master replies that it is only a temporary effect, which he attempts to demonstrate by deactivating the suppression device.
However, the silence persists and the calculations do not resume. They go outside, and find all the Logopolitans dead, crumbling to dust, and the city itself collapsing. The Master thinks this is some sort of trick and tries to have Nyssa strangle the Monitor, but the control device ceases to function. He tries to increase the device's power, but this causes it to fall apart as local decay increases. The Monitor explains the situation: the universe had long ago passed the point of heat death. To stave off final collapse, the Logopolitans had been modelling a number of temporary Charged Vacuum Emboitments, like the one through which the TARDIS had been previously transported into E-Space. The excess entropy generated by the universe had been passing through the CVEs to other universes. However, The Master's interference has caused the CVEs to close and the universe is now dying at last.
Realising that he and the Master must work together, the Doctor orders his companions into his TARDIS, and has the Watcher take them out of spacetime. However, Tegan refuses to co-operate and follows the Doctor, Master and Monitor back to the Logopolis control room. The Monitor reveals that they had been completing a program to make the CVEs permanent, and prepares to use it on one of the surviving CVEs, but entropy takes hold of him and he disintegrates before their eyes. The Doctor dismantles the computer and realises the program is stored in bubble memory that they can use with the real Pharos Project. The Doctor, Master and Tegan escape from Logopolis in the Master's TARDIS.
Adric and Nyssa watch helplessly in the Doctor's TARDIS as a portion of the universe is wiped out by encroaching entropy — including Traken. On Earth, the two Time Lords reconfigure the Logopolitan program and feed it into the Project's computers, but the Master points out that the transmitter is pointed away from the last surviving CVE. After speaking with the Watcher, Adric brings the Doctor's TARDIS to Earth as the Doctor and the Master run on foot to realign the dish. The Doctor's companions distract the guards and the two Time Lords get to the dish's control room, hooking up a light speed overdrive from the Master's TARDIS to ensure the signal gets to the CVE in time. Upon transmission of the program, the CVE begins stabilising.
The Master's co-operation with the Doctor has been a ploy, however. Holding the Doctor at gunpoint with his Tissue Compression Eliminator, he transmits a message to the peoples of the universe, saying that if they do not acknowledge his rule, he will send a signal to close the CVE and restart the collapse. The Doctor climbs onto the radio telescope's gantry to disconnect the power cable, and the Master attempts to prevent him by tilting the dish 90 degrees. The Doctor succeeds in disconnecting the cable, but falls off the gantry. As he hangs on to the disconnected cable, visions of old enemies mock him. Losing his grip, the Doctor plunges to the ground. The Master enters his own TARDIS and it dematerialises.
The Doctor's companions run to the spot where he has fallen. Dying, the Doctor experiences visions of the companions that have accompanied his current form and observes, "It's the end... but the moment has been prepared for." They turn to see the Watcher approach, and as he does so he merges with the Doctor. Nyssa realises that the Watcher was the future Doctor all the time. As the companions look on, the Fourth Doctor regenerates into a new, younger body — the Fifth Doctor.
- Doctor Who — Tom Baker
- Doctor Who — Peter Davison
- Adric — Matthew Waterhouse
- Tegan Jovanka — Janet Fielding
- Nyssa — Sarah Sutton
- The Monitor - John Fraser
- The Master — Anthony Ainley
- Vanessa — Dolore Whiteman
- Detective Inspector — Tom Georgeson
- Security Guard — Christopher Hurst
- Writer - Christopher H. Bidmead
- Assistant Floor Manager - Val McCrimmon
- Costumes - June Hudson
- Designer - Malcolm Thornton
- Executive Producer - Barry Letts
- Film Cameraman - Peter Hall
- Film Editor - Paul Humfress
- Incidental Music - Paddy Kingsland
- Make-Up - Dorka Nieradzik
- Production Associate - Angela Smith
- Production Manager - Margot Heyhoe
- Script Editor - Christopher H. Bidmead
- Special Sounds - Dick Mills
- Studio Lighting - Henry Barber
- Studio Sound - John Holmes
- Visual Effects - John Horton
- Producer - John Nathan-Turner
- Director - Peter Grimwade
- The exact nature of the information given to the Doctor and, later, Adric in unheard conversation with The Watcher is never revealed.
- The Logopolitans are vital to the stability of the Universe. They discovered long ago that the Universe had passed the natural point of total collapse and so used block transfer computation to create Charged Vacuum Emboitments into other universes.
- The entropy field caused by the destruction of Logopolis also destroys a portion of the universe; Traken and Mettula Orionsis (Traken's star) are mentioned.
- The Doctor's transmission of the Logopolis program saves the rest of the Universe, starting with the constellation of Cassiopeia.
- On Logopolis, sonic projectors are said to "create a temporary zone of stasis". The mathematics of block transfer computation is a way of modelling space/time events through pure calculation
- The TARDIS cloisters are seen for the first time.
- The Cloister Bell is described as 'a sort of communication device reserved for wild catastrophes and sudden calls to man the battle stations'.
- The Doctor states that the TARDIS was in Gallifrey for repairs when he 'borrowed' her. "There were rather pressing reasons at the time"
- There are references to the TARDIS' faulty chameleon circuit and a demonstration of how it could function.
- After picking up Adric and Nyssa, the Watcher disconnects 'the entire co-ordinate sub-system' of the Doctor's TARDIS, which takes it "out of time and space".
- The Master's TARDIS disguises itself as a police box, a tree and an Ionic column at various times.
- The Master suggests "we reconfigure our two TARDISes into time cone inverters... We create a stable safe zone by applying temporal inversion isometry to as much of space/time as we can isolate.".
- This story was the last to feature Tom Baker as "the current" Doctor. He would reprise his role only in recorded links for the video release of the incomplete Shada in 1992 and then on the Children in Need special Dimensions in Time (1993). As of 2007, Tom Baker holds the record for having the longest tenure (seven years) as the Doctor on-screen.
- The key plot point of shunting excess entropy into another universe was previously used in Isaac Asimov's novel The Gods Themselves.
- This serial arguably — as pointed out in About Time 5 by Lawrence Miles and Tat Wood — has the largest body count of any Doctor Who story, albeit not graphically shown, as the destruction of Logopolis apparently causes a significant portion of the entire universe to be swallowed by a wave of entropy. At the very least, the Traken Union is destroyed, which would put the death toll in the billions and making the Master a mass killer on an unprecedented scale, albeit not by intent.
- Tom Baker's face was electronically removed from the closing credits of Part 4, and the titles were re-shot with Peter Davison's face for the following story, Castrovalva.
- Part 4 of this story was the last time the lead character was listed in the credits as "Doctor Who" for the next 24 years. Beginning with the next story, Castrovalava, until the series' cancellation in 1989, the character was credited simply as "The Doctor". The 1996 television film did not have an on-screen character name credit for either the Eighth Doctor or Seventh Doctor, however the press kit for the film credits them as "The Doctor" and "The Old Doctor", respectively. The 2005 relaunch returned the credit to "Doctor Who", and then again to "The Doctor" in The Christmas Invasion.
- Also, Episode 4 was the first to credit two actors as "Doctor Who" or "The Doctor" when a regeneration scene was involved. It also happened at the end of Episode 4 of The Caves of Androzani. In both instances, Peter Davison was billed second.
- With his cameo at the very end, Peter Davison became the first person to be in both Doctor Who and the Tomorrow People
- Part 1 - 7.1 million viewers
- Part 2 - 7.7 million viewers
- Part 3 - 5.8 million viewers
- Part 4 - 6.1 million viewers
to be added
- Ursula Street, Battersea, London (Outside Vanessa's house)
- Cadogan Pier, Chelsea Embankment, London (the barge the Doctor lands his TARDIS on)
- Amersham Road (A413), Denham, Buckinghamshire (the motorway the Doctor lands the TARDIS next to)
- Albert Bridge, London (location where the watcher first beckons from)
- Crowsley Park BBC Receiving Station, Blounts Court Road, Sonning Common, Berkshire (doubled as the Pharos Project for some external shots)
- The Lovell Telescope at Jodrell Bank was used for the filming of the location scenes at the Pharos Project.
- BBC Television Centre (TC3 & TC6), Shepherd's Bush, London
Discontinuity, Plot Holes, Errors
- This story features the Doctor's TARDIS materialising around the Master's TARDIS and creating a gravity bubble and the recursive phenomena of infinite TARDIS'es nesting within each other. Two TARDISES's materialized "inside" each other in The Time Monster, but did not happen when the TARDIS materialised inside Professor Chronotis's rooms (actually his TARDIS in disguise) in the untelevised Shada. Chronotis's room was not a complete TARDIS; it was not dimensionally transcendant.
- Why is there a litter bin next to the 'Take Your Litter Home' sign in part one? Such bins are often meant for incidental litter only, not for large amounts of trash. Reminders of such are sometimes posted.
- Why does the policeman take the doll-like corpses so seriously? Because he recognizes one of them as being the first constable seen in the story.
- At the beginning of part 2, when The Doctor and Adric are going back to the TARDIS to escape the policemen, the Doctor opens the door to the right, however Adric goes through a door that is open to the left.
- Surely the Doctor's plan of flooding the TARDIS to flush-out the Master is absurd nonsense. The Doctor was feelinmg very fatalistic at this point. It is doubtful there is a normal procedure of what to do when your arch-nemesis creates a gravity bubble within your TARDIS.
- When the Master puts the bracelet onto Nyssa's wrist, part of it falls off.
- In part four, when the Master enters his TARDIS, his shadow stays after it dematerialises.
- Tegan appears amazingly reconciled to the extraordinary events happening around her. In particular she does not appear to comment on the size of the TARDIS. She witnesses the regeneration of the Doctor without any evident wonderment and without questioning what is happening. Not everyone reacts to surprise the same way.
- The only indication that the Watcher is the Doctor's future self is Nyssa saying, 'so it was the Doctor all along'. But how does she know? Possibly Adric exlained some detail off screen and she she was working it out
- It is never really explained how/why the Watcher has come into existence for this regeneration and not previous or future ones. It's a process that is not always necessary. It's been rather clearly shown that the Doctor does not have the smoothest time with regeneration. Sometimes he needs a little help, even if from a future part of himself.
- The Lock on the Master's TARDIS changes place in part 1. The chameleon circuit adjusted it.
- This story continues a loose arc of three serials featuring the Master. The trilogy began with The Keeper of Traken and concluded in Castrovalva. Although the Master does not appear until Part 3, his laughter can be heard in the first two episodes and Anthony Ainley is credited accordingly.
- This story picks up soon after the events of The Keeper of Traken, at the end of which the Master secured a thirteenth regeneration by killing Nyssa's father Tremas and stealing his body. The Doctor and Adric briefly discuss Romana's departure and decide to postpone their trip to Gallifrey, where the Doctor had been under orders to return his former companion.
- Before the Doctor falls from the dish, the enemies that mock him are the decaying Master (DW: The Deadly Assassin), a Dalek (DW: Destiny of the Daleks), the Pirate Captain (DW: The Pirate Planet), the Cyberleader (DW: Revenge of the Cybermen), Davros (DW: Genesis of the Daleks), a Sontaran (DW: The Invasion of Time), a Zygon (DW: Terror of the Zygons) and the Black Guardian (DW: The Armageddon Factor).
- As he is lying on the ground after falling the Doctor sees visions of all the companions that previously accompanied his fourth incarnation: Sarah Jane Smith (DW: Terror of the Zygons), Harry Sullivan (DW: The Sontaran Experiment), Brigadier Lethbridge-Stewart (DW: Invasion of the Dinosaurs), Leela (DW: The Robots of Death), K-9 (DW: The Armageddon Factor), Romana I (DW: The Stones of Blood) and Romana II (DW: Full Circle).
- The exact date of 28 February 1981 for this story is set in Four to Doomsday, as the Doctor is trying to get Tegan to Heathrow in time for her flight. Logopolis and Four to Doomsday both happen on the same date. This synchronicity is also shared by the stories DW: The War Machines, The Faceless Ones, and the first episode of The Evil of the Daleks, which all occur around the same date in 1966.
- PDA: The Quantum Archangel briefly shows an alternate timeline where the destruction of Logopolis did result in the death of the universe.
Video, DVD, and audio releases
- Commentary by Tom Baker, Janet Fielding and Christopher H. Bidmead
- A New Body at Last - A 50-minute documentary looking at the transition from Tom Baker to Peter Davison, featuring many of the actors and production team involved, including exclusive behind-the-scenes footage of the regeneration.
- Nationwide - Interviews from the BBC news magazine show with Tom Baker and Peter Davison.
- Pebble Mill at One - Peter Davison interviewed on the long-running BBC lunchtime show.
- BBC News Reports on Tom Baker's wedding, the announcement of Tom Baker's departure and Peter Davison's arrival.
- Music-Only Option - The original score for this story is included on a separate soundtrack.
- Trailers & Continuity Announcements
- Radio Times Billings (PDF DVD-ROM)
- BBC Enterprises Literature (PDF DVD-ROM)
- Doctor Who Annual 1982 (PDF DVD-ROM)
- Photo Gallery
- Production Subtitles
- Main article: Logopolis (novelisation)
- A novelisation of this serial, Doctor Who - Logopolis, written by Christopher H. Bidmead, ISBN 0-426-20149-3, was published by Target Books in October 1982. It was number 41 in the series of 156 Doctor Who novelisations published by Target.
- BBC Episode Guide to Logopolis
- Outpost Gallifrey Episode Guide: Battlefield
- Doctor Who Reference Guide: Detailed Synopsis - Logopolis
- A Brief History of Time (Travel): Logopolis
- The Locations Guide to Doctor Who - Logopolis
- Five-Minute Logopolis — Parody version