The Mind of Evil (TV story)

The Mind of Evil was the second serial of season 8 of Doctor Who.

It brought a radical change in the way UNIT was portrayed. Instead of being a primarily investigative body interested in alien or unexplained phenomena, here UNIT was mostly seen as a simple security force, guaranteeing the safety of international diplomats. In other words, the "United Nations" portion of their acronym was stressed over the "Intelligence Taskforce" bit — as later happened in such stories as Day of the Daleks and The Time Warrior. This forced the plot to partially concern itself with international espionage, thus lending an almost Bondian veneer to proceedings. The internationalism of the plot even allowed for highly unusual scenes of the Doctor conversing in a real language — Hokkien, a dialect of Chinese — other than English. Indeed, as of the eleventh BBC Wales series, The Mind of Evil was the only story which used English subtitles for the Doctor's speech.

Meanwhile, the main plot about the mind-control device was something writer Don Houghton intentionally included as an homage to.

Behind the scenes, The Mind of Evil went somewhat over budget, thanks in no small part to one of Doctor Who's rare usages of a real helicopter in the concluding episode. An unimpressed Barry Letts therefore withdrew director Timothy Combe from his informal "director's rota", and Combe never worked on the programme again. Following the loss of all six its 625 line PAL colour videotapes, which were either erased for reuse or destroyed, The Mind of Evil became the "most missing" serial of the Jon Pertwee era, in that not even a frame of it survived in colour on any broadcast-quality medium. Fortunately, the whole of it remained available as 16mm black-and-white telerecordings due to some of BBC Enterprises' overseas customers requiring this format for transmission. Additionally, a few colour clips survived from an off-air home recording, which allowed for some scenes to be recoloured for the 1998 VHS release. Its DVD release marked its complete restoration, with all six episodes recoloured.

Synopsis
Professor Emil Keller has created a machine that can pacify even the most dangerous of criminals. But when the Doctor and Jo arrive at Stangmoor Prison for a demonstration, things start to go horribly wrong - especially when they discover that the Doctor's old enemy is responsible for the machine.

What could he possibly want from the criminals? And what connects him with an impending World Peace Conference?

Episode one
The Third Doctor and Jo Grant arrive at Stangmoor Prison to view a demonstration of the Keller Machine, developed by Swiss scientist Emil Keller, which is claimed to cure anti-social behaviour by extracting evil impulses from the mind. Professor Kettering, acting on behalf of the absent Keller, reports over a hundred successful tests on European prisoners. The Doctor's open scepticism is apparently justified when the machine overloads, and the subject, a hardened criminal named Barnham, is rendered comatose. Meanwhile, UNIT is busy overseeing security at the first World Peace Conference. Things are not going too well, as the Brigadier attempts to calm Captain Chin Lee, furious at the apparent theft of classified documents from the Chinese delegation. Later, Chin-Lee reports even worse news: the Chinese delegate is dead. Meanwhile, Captain Yates is assigned to lead a small UNIT platoon in disposing of the Thunderbolt, an outlawed nerve gas missile.

Arthur Linwood, a medical student witnessing the Keller demonstration, is found dead near the Keller Machine, his face frozen in terror, covered in bites and scratches. His medical history shows a morbid fear of rats, but there are no traces of any in the prison. Professor Kettering is examining the machine when it becomes active, despite his not even having touched the controls. Kettering has a vision of waves of water and dies of an apparent heart attack. Investigating Kettering's death, the prison medic, Dr Summers, is mystified that the symptoms are consistent with death by drowning; Kettering had a morbid fear of water. The machine's activity also appears to coincide with an increase in hostility in the prison population. The Doctor is worried that the machine has power over people's minds and is growing more powerful. As suspected, Kettering's medical files show he had a morbid fear of water.

Later, as the Doctor examines the machine, it activates again. He is seized by terror as the room appears to erupt in flames...

Episode two
Jo enters the room and breaks the hold that the machine had over the Doctor. The Doctor is initially cross at Jo for disobeying his orders. Jo presents the report on Kettering's death and he tells Jo that he saw fire when the machine had a hold of him. He tells Jo that he once saw a planet go up in flames and the machine used this experience to attack him. Yates enters with orders to bring the Doctor back. The Doctor refuses and Yates tries to use force until the Doctor counters him with Venusian Karate. Yates tells the Doctor about the peace conference and the death of the Chinese Delegate which sparks the Doctor's interest. He leaves Jo in charge of the prison and orders her to get the Governor to lock and bar the doors.

Chin Lee is using a public payphone whilst Benton is waiting at a safe distance, keeping an eye on her. Lee leaves the booth and uses her mind control to cause Benton to faint. Lee escapes. When Benton awakens he tries to pursue her but she is hidden.

Benton reports to the Brigadier who disbelieves his story of fainting and is cross. The Doctor and Yates enter.

An engineer outside UNIT headquarters is working on the telephone line. After finishing his "work", he removes a latex mask, revealing himself to be the Master who has bugged the line and hears the plans for the movement of the missile. The Master removes his engineers overalls to reveal a suit and tie underneath, and is then picked up by a smart limousine.

Before the Doctor agrees to help the Brigadier he makes him promise that he will contact the ministry and put a ban on the Keller Process. Once the Brigadier agrees to this they head off to meet the new Chinese Delegate, Fu Peng. Yates makes a phone call (overheard by the Master) organising a motorcade for the missile at seven o'clock the next day.

When the Brigadier and the Doctor enter the Chinese Delegate's hotel room, he is initially cold towards them until, to the Brigadier's disbelief, the Doctor speaks with him in Chinese. The two go off to drink tea together, leaving the Brigadier a bit miffed.

A cleaner is shown into one of the cells in the prison.

Barnham is fit as a fiddle and has a conversation with Jo whereby he admits that he remembers nothing from before he awoke in the hospital bed. Summers tells Jo that the process has removed all negative impulses from Barnham - rendering him somewhere between an idiot and a saint.

The clamour of the prisoners draws the guard supervising the cleaner out of the cell momentarily. The cleaner hides a gun under the pillow. Shortly afterwards a prisoner, Mailer, is brought in. The guards distract themselves by playing checkers whilst Mailer checks for the gun.

Whilst the Doctor and Peng chat, the Brigadier doesn't get to ask any of his questions. They are soon led out with the Brigadier frustrated at the man's rudeness.

The food arrives and Mailer takes the guards hostage.

The Doctor speculates that there must be a link between the Keller Process and the death of the delegate. Yates presents the Brigadier with the plans for the movement of the missile. The Brigadier makes a comment with regards to Benton losing track of the Chinese girl. The Doctor realises that this is the link between the two things. He suggests that the Brigadier puts out a general alert for Lee.

Lee meets up with the Master. He says that he has another task for her. She is distressed by this but the Master hypnotises her. Her task is to kill the American delegate. He sends her away.

The prisoners are mutinying led by Mailer. Mailer says they need more hostages and goes to the medical ward.

Jo and Summers are in a state of panic when Mailer bursts in and takes them hostage.

The Brigadier is told of the fact that Lee has returned back to the Chinese Delegate's room and rushes off.

Lee rings the American Delegate and tells him that his Chinese counterpart wishes to see him. The American Delegate is unsure but eventually complies. Lee opens the door and hides. The American Delegate let's himself in. Lee closes the door behind him and asks him to sit down. She switches the light off and the whirring resounds in the delegate's ears. He sees the approach of a dragon and cowers in fear.

Episode three
Chin Lee is interrupted by the Brigadier and the Doctor who see the dragon. The Brigadier fires his gun and the dragon disappears. Lee falls into a faint. The Doctor says it is a collective hallucination. The American Delegate is on the floor unconscious through acute shock. The Chinese Delegate finds an amplifier behind Lee's ear and believes it is linked to the Keller Machine.

The riot at the prison continues. Mailer is told that the prison is surrounded but he is still confident as the prisoners have hostages.

The Doctor considers Lee to be a conduit to a larger threat. Lee awakes and the Doctor begins to interrogate her in Cantonese.

Mailer is told that the phone lines are down. They go into the cell where Jo and Summers are. Summers tries to attack the guard but is thwarted. He is told he is to send a message to the Governor demanding a safe exit from the prison. Jo is left alone in the cell.

There is an issue with the crane needed to move the missile which is delaying the process.



The Doctor brings Lee to the Brigadier. Yates rings and tells the Brigadier of the hold up with the missile. Yates asks after Lee. The Brigadier tells him everything.

The Master overhears this and orders his driver to take him to the prison.

Lee tells the Brigadier of her association with Keller. Lee says she has been in the processing room but can't picture it. The Doctor says she is suffering from post-hypnotic block and realises that the Master is behind all this. Emil Keller is the Master.

Jo is being moved at gunpoint.

The Governor is refusing to negotiate. Summers is furious. The Governor intends on waiting it out. Summers asks what he plans on doing with Jo. The Governor decides to inform UNIT.

The Doctor tells the Brigadier to let Lee go. The Brigadier is informed of Jo's position.

Mailer shouts through the door that they are to be freed or Jo will be killed. The Governor agrees to talk. Barnham arrives in a daze. Jo uses the distraction to disarm Mailer. The guards storm the prison. A fight breaks out. Jo ends up holding Mailer up at gun point and handing him over to the Governor.

Later the Master arrives at the prison. The Governor tells of the issues they have been having with the machine and the involvement of UNIT. The Master asks to see Mailer. He is taken to him. Mailer tries to hit the Master, but the evil Time Lord overpowers him. The Master whispers that he is here to help him. He gives Mailer weapons and says he is going to help him escape. The plan is to overpower the guards and, as soon as possible, make everything look like it is running normally. The Master and Mailer use smoke grenades and guns to escape and take over the prison.

Jo, Summers and Barnham are disturbed by the alarm.

The Master orders the prisoners to stay in their cells until the fumes have cleared. He puts a blocking device on the phone.

Jo is taken hostage by a prisoner.

The Master stops the alarm.

The Doctor arrives at the prison. The Master, who is now in charge, allows him in. As soon as he is through the gates, Mailer jumps out with a gun. The Doctor is distinctly unphased and allows himself to be led to the Master. The Doctor says that if the Master has hurt Jo he will not fail in taking revenge. The Master pulls a gun and says he needs the Doctor's help. The Doctor warns that that machine will kill the Master. The Master does acknowledge it has taken on a mind of its own but that is what he wants the Doctor to remedy whilst he is elsewhere. When the Doctor questions as to what the Master considers more important, the Master says that he intends on stealing the missile that UNIT are moving.

Yates contacts the Brigadier to say they intend on driving through the night to get back on schedule.

The Master tells the Doctor that he intends in launching the missile, wiping out the Peace Conference and plunging the world into war. The Doctor turns the desk over and runs. The guards try and get him but he eludes them.

Jo and Summers hear the gunfire and wonder if the Doctor has arrived. They call for him.

The Doctor sneaks back into the prison and hears their calls. He runs into the processing room where he is met by the Master and Mailer. Mailer handcuffs him into the processing chair before he is asked to wait outside. The Master says he has repaired the machine and wants to see how long the Doctor can hold out against it. He takes the amplifier out of the Doctor's pocket and switches it round so that the machine can project into his brain. He turns the machine on and leaves. The Doctor struggles to be free as the machine grinds into gear. He sees images of foes from his past, including a Dalek, looming towards him.

Episode four
The prisoners moan, clutching their ears and hear the moaning sound. The Master is also affected and goes to the Processing Room. He struggles to the machine and switches it off. He checks on the Doctor. Only one of his hearts are beating. He tries to kick start his other heart.

A prisoner comes to get Summers. He objects but is forced. Jo is told that she is being saved for the machine.

The Doctor awakens. The Master tells him that he was within an inch of dying. The Doctor is dispirited and says that no one can control the machine as he knows its secret; he encloses a creature that feeds on the evil of the mind. The Master considers this nonsense. He tells Mailer to put him in the cell with Jo, telling the Doctor that if he doesn't comply Jo will be next. Mailer helps the Doctor to the cell. He tries to fight with him but is too weak. He is thrown in the cell where he falls to the ground. Jo rushes to get water. The Master presents himself to her. He implores her to talk some sense into the Doctor before leaving and ordering the cell to be constantly guarded. He tells Mailer to clear everybody out of the wing apart from the Doctor and Jo. Once the Master leaves, Jo calls for help urgently. The guard enters and Jo begs him to get Doctor Summers.

The machine is reading high. The Master insists that the machine cannot harm him as he is stronger than it. He brought it here and gave it the minds it needed. He is overpowered by the machine and cannot switch it off. The Master sees his own greatest fear: a giant image of the Doctor, which looms above him laughing. He runs out the room and bolts the door. He says he will give the machine no more minds until it complies.



Summers has been brought to the cell. He remarks that the Doctor's biology is extraordinary and not human but he has sustained physical and mental shock and is in some form of coma. He can offer no help apart from some tablets he should take if he awakens. He is led away. Jo tries to give a semi-conscious Doctor the medicine but he refuses saying he has the wrong metabolism and that it would probably kill him. He falls unconscious again. Jo weeps.

The Master is exhausted. Mailer enters and he pretends all is well. The Master orders him to guard the Processing Room at all times. Mailer asks why they are not escaping. The Master explains they would be caught by the police or the army but he has a plan which will get them all a free pardon, unlimited money and a ticket to anywhere in the world. He shows Mailer a projection of the missile and explains that Mailer and the prisoners are to hijack it. Once he has it he will aim it at the Peace Conference. The Master shows Mailer a map of where they are going to intercept it.

A guard enters the cell. The Doctor is still unconscious. Jo asks for food. As soon as they are alone, the Doctor jumps up and thanks Jo.

The Master gives the prisoners their orders and they set off.

The food comes and Jo knocks the tray into the face of the guard before karate chopping him in the back of the neck. When the other guard enters, the Doctor strikes him over the head with the tray and they escape, locking both guards into the cell. They run into the Master's office. Jo sees that a search party is already being formed outside. The Doctor says that they will be expecting them to make a break for it but he intends on laying low for a while. Jo turns on the projector and sees the missile. The Doctor tells her of the Master's plan.

The prisoners are in place. They see the missile and perform the ambush. A roadblock is created. Yates contacts the UNIT headquarters but a gunshot incapacitates him.

The Brigadier receives the message but there is no further response.

Yates regains consciousness and sees the prisoners taking the missile. He runs to a motorbike and pursues them.

The Brigadier has figured out where the missile was hijacked and heads off there by helicopter.

Mailer unloads the missile into a warehouse - watched all the time by Yates. He is spotted and tries to escape but falls off his bike. The prisoners take him captive.



The Brigadier is talking to an injured Benton at the scene of the ambush. He sees that both Yates and a bike is missing so realises that he may have pursued. Benton says he recollects seeing a black van like the police use. The Brigadier consults a map and says it probably came from Strangmoor.

The Doctor and Jo are still waiting but the Doctor is eager to go and deal with the creature. He describes it as a mind parasite that feeds in evil and is the deadliest threat on humanity since the beginning of time. Jo sees the Master leaving. The Doctor sees his chance to get to the Processing Room and deal with the machine.

Inside the Processing Room, the machine, now able to teleport itself, disappears.

A prisoner is looking for the Doctor when the machine appears in one of the cells he is searching in. The prisoner is affected by the machine and then dies; the machine disappears once more. The Doctor and Jo find the prisoner and note that he looks terrified. The Doctor speculates that the creature has learnt to move. They go to the Processing Room and find the machine gone. Mailer and another prisoner enter and hold the Doctor and Jo at gunpoint. The machine appears behind them. The Doctor and Jo hide. The prisoner is killed and the machine disappears. The Doctor and Jo emerge, but the machine appears directly in front of them.

Episode five
The machine does nothing except disappear again. The Doctor suggests that it followed Mailer as he had a higher concentration of evil. The Doctor and Jo find Barnham outside and they all leave together.

The Brigadier is in a helicopter above the prison looking for the missile. He sees no sign of it but will continue to look.

Jo sees the helicopter and they try and get its attention but they are found by a prisoner. Barnham fights with the prisoner but the Doctor uses Venusian Karate to get Barnham off of him. They are soon surrounded by prisoners.

The Master and Mailer argue over the phone. The Master says that it is Mailer's fault that Yates followed them. Mailer wants the Master to come back to deal with the machine but he refuses to leave. Mailer says that if he doesn't come back, Mailer and the prisoners will leave and tell the world about the Master's plans. The Master agrees to come back. Once he hangs up the phone he tells Yates to stop feigning unconsciousness and tells him his plan. He explains that he is a hostage in case anything goes wrong and leaves him alone.

The prisoners present the Doctor, Jo and Barnham to Mailer. Mailer refuses to talk to Barnham. Mailer pulls a gun on the Doctor. The Doctor asks why Mailer is working with the Master. Mailer tells of the promises that the Master has made. The Doctor and Jo say that the Master won't deliver. Mailer asks if the Doctor can make him a better offer. When he says he can't, Mailer sends them back to the cells.

The Brigadier tells Major Cosgrove that he considers the missile to be in the prison. Cosgrove wants to attack but the Brigadier says the prison used to be a fortress and that they wouldn't be able to get in. Cosgrove asks if there was a secret underground passage. They check a map and find one. They are interrupted by report of a car containing the Master entering the prison. The Brigadier says they will use the secret passage and a Trojan Horse to gain entry to the prison.

The Master presents himself to the Doctor and Jo. They are playing checkers and keep him waiting until the game is complete. The Doctor refuses to control the machine and says he has no reason to help the Master. The Master says that it would save lives. The Doctor counters that it would be the lives of his mercenaries. The Master says that the Doctor has misunderstood him and tells him that Mailer will shoot Jo if he doesn't comply. Forced into helping the Doctor says that he does have a theory that might inhibit the machine. He is lead away whilst Jo remains in the cell.

The Brigadier briefs his men about the plan. Benton returns after discharging himself from hospital. He wants to come on the assault. The Brigadier eventually agrees. He asks after Yates and the Brigadier has to admit they have heard no news.

Yates has freed himself from his bonds. A guard comes to check on him. Yates overpowers him, steals his gun and escapes.

The Master begs the Doctor to hurry. The Doctor explains his plan is to put a metal coil connected to a device of his own creation around the machine. When the device is switched on it will create a fake impulse similar to the human brain which will confuse the machine and render it in one place. The Doctor goes in with the coil. The machine senses him and as he approaches the coil bursts into flames. The Doctor sees visions of the Daleks. He manages to put the coil around the machine and shouts to the Master to turn the device on. The visions stop. The Master calls for Mailer before he congratulates the Doctor. The Doctor warns it will not hold the machine for long. The Doctor is returned to his cell where he tells Jo of what he has done. They share scraps of food they find on the floor and drink water as the Doctor tells Jo of the time he was trapped in the Tower of London with Walter Raleigh.

A van approaches the prison. The Brigadier, disguised as a delivery man in flat cap and overalls, alights and rings the bell. Three UNIT soldiers emerge unseen from the back and stand behind the van. The Brigadier says he has provisions for the prison. The prisoner tries to send him round the back, but the Brigadier says his van won't fit. The prisoner tries to send them away, but the Brigadier says it will look strange if that was the case. The prisoner radios for guidance and it is agreed the "delivery man" can come in. The soldiers follow the van in and disable the two prisoners on the gate. UNIT ambush the prison. The Brigadier announces through a megaphone that the prison is now in military hands; however, the megaphone is then shot out of his hand by an unseen assailant.



The Doctor and Jo listen and hope that UNIT are swift before they start killing hostages.

There is a protracted firefight between UNIT and the prisoners. Many of the prisoners are killed. The Brigadier goes off to find the Doctor as more UNIT soldiers enter.

Mailer enters the cell and says he wants to use the Doctor and Jo as a human shield to get out of the prison. The Doctor leads the way then Jo then Mailer. As they go down some stairs, Jo falls backwards onto Mailer. Mailer grabs hold of her and points his gun at the Doctor. A gunshot resounds through the prison.

Episode six
The shot was not from Mailer's gun but the Brigadier's, and Mailer slumps forwards — dead. Benton tells the Brigadier that the Master got away. The Doctor tells the Brigadier that the missile is not in the prison and then questions how well he is doing.

The Master arrives at the hangar and begins to direct the missile.

UNIT have managed to get the prison back under control. A soldier says they found Barnham hiding and Jo stops them from locking him up with the other prisoners. The Doctor explains how Barnham came to be like he is. They begin to consult a man when Yates radios through from the mobile HQ. He tells the Brigadier where the missile is and the Brigadier says he will come out to meet him.

The coil around the machine begins to pop and smoke.

The Brigadier leaves Benton in charge of the prison as "Acting Governor". He bids goodbye to the Doctor in an arrogant manner, but the Doctor warns him that all might not be as straightforward as he envisages. He tells the Brigadier he intends on staying here to destroy the machine.

The machine tries to move. The coil bursts into flames. The controls set alight. Finally the machine moves in front of two guards and kills them.

The Doctor has finished his plan. He heads off with Jo in tow. Summers calls to ask Benton about some medical supplies. Barnham says he'd like to talk to Dr Summers, but Benton says Barnham can talk to whom he likes, as he's busy at the moment. Benton turns back to the phone call, and Barnham slopes off.

The Doctor and Jo find the guards. The Doctor says the machine has stored up all its energy and blown the circuits, meaning that it's stronger than ever. Barnham wanders by as the machine appears. Jo and the Doctor are affected, but as Barnham wanders in the machine stops. Barnham recollects the room and runs out, which causes the machine to start again. The Doctor grabs Barnham and forces him to the machine, realising the goodness in Barnham's brain — which has no evil impulses — neutralises the machine.

The Brigadier arrives at the mobile HQ. Cosgrove tells him that the missile has an abort process that can be controlled remotely.

The Doctor has unearthed the creature that lives inside the machine. Jo wants him to destroy it but the Doctor says that only an atomic explosion or an enormous charge of electricity can kill it. The Doctor goes to see Benton and asks him to arrange for a cable and a power boost from the National Grid. The phone rings. It is the Master. He asks if the tables have been turned.

Summers enters and orders Barnham back to the hospital. He drags him away and the machine starts again. Jo drags him back.

The Master tells the Doctor that he still intends to fire the missile to begin World War Three, render the planet in ruins and then emerge as the leader. The Doctor suggests a deal. He will give the Master the dematerialisation circuit for his TARDIS if he hands over the missile. The Master agrees and says that just those two should be present at the hand over. As soon as the Master hangs up the Doctor tells Benton to contact the Brigadier and cancel the attack.

Summers is convinced to leave Barnham with Jo.

The Doctor tells the Brigadier of his plan. The Brigadier says he has other plans up his sleeve. The Brigadier tells Cosgrove to stay on the line to missile control and tells Yates to clear the area around the hangar.

Jo doesn't understand why the Doctor is so anxious. The Doctor doesn't want to give the Master the circuit and allow him to escape and cause damage to other planets. All of a sudden the Doctor comes up with a plan which means both the Master and the machine will be destroyed.

The Master flicks a switch on the console and takes out a circuit.

Barnham picks up the machine and is led away.

The Brigadier tells the Doctor that they can't explode the missile manually. The Doctor says that the Master would obviously disconnect the abort circuit. The Brigadier says that they have no choice but to give the Master back his dematerialisation circuit. The Doctor is still concerned and says he has another plan.

Jo and Barnham are driven to the hangar in a police van by the Doctor. The Master pulls a gun as the Doctor emerges. The Doctor distracts the Master as Barnham and Jo sneak out the back. The Doctor and the Master have a stand off about the handing over of the circuit. Suddenly the Doctor uses Venusian Karate to knock the Master to the ground. Barnham drops the machine by him and all three run causing the machine to effect the Master. Jo contacts the Brigadier whilst the Doctor goes to look at the console. He repairs the abort circuit as a helicopter lands. As they run to the helicopter, Barnham stops to help the Master. The machine stops and the Master knocks Barnham down and runs him over in the police van in his effort to escape. The Doctor and Jo run back to check on Barnham, but he is dead. They escape in the helicopter. As the hangar explodes, Jo looks on in tears.

Back at the Governor's office, Jo and the Doctor mourn Barnham's death. The Brigadier urges them to be thankful that they at least managed to rid Earth of the machine and the Master. The Doctor isn't convinced that the Master is gone, but the Brigadier is confident that even if he wasn't killed in the explosion, he wouldn't get very far without his dematerialisation circuit. The Doctor begins to agree, only to realise when he checks his pockets that the circuit is gone; he must have dropped it back at the hangar. While the group is wondering what became of it, the phone rings. Benton answers it, and hands it over to the Doctor saying it's the Master calling. The Master gloats that he is alive and well, much to the Doctor's frustration. He adds that, thanks to the Doctor, his TARDIS is now working once again, and that they won't be seeing each other for quite some time. The Master vows he will one day return to destroy Earth, and the Doctor along with it, adding as a final insult to the Doctor "Enjoy your exile!"

Jo tries to lift the Doctor's spirits by reminding him he won, but to no avail. The Doctor is annoyed that the Master is free to come and go as he pleases, while he is stuck on Earth with the Brigadier. The Brigadier grins at that last remark.

Cast

 * Dr. Who - Jon Pertwee
 * Brigadier Lethbridge Stewart - Nicholas Courtney
 * Jo Grant - Katy Manning
 * Captain Mike Yates - Richard Franklin
 * Captain Chin Lee - Pik-Sen Lim
 * Prison Governor - Raymond Westwell
 * Dr. Summers - Michael Sheard
 * Professor Kettering - Simon Lack
 * Barnham - Neil McCarthy
 * Corporal Bell - Fernanda Marlowe
 * Linwood - Clive Scott
 * Chief Prison Officer Powers - Roy Purcell
 * Senior Prison Officer Green - Eric Mason
 * Prison Officers - Bill Matthews, Barry Wade, Dave Carter, Martin Gordon
 * - Roger Delgado
 * Sergeant Benton - John Levene
 * Mailer - William Marlowe
 * Vosper - Hayden Jones
 * Fu Peng - Kristopher Kum
 * Senator Alcott - Tommy Duggan
 * Charlie - David Calderisi
 * Major Cosworth - Patrick Godfrey
 * Fuller - Johnny Barrs
 * Main Gate Prisoner - Matthew Walters

Uncredited cast

 * Main Gates Prison Officer - Leslie Weeks (DWM 208)
 * Demonstration Audience - Desmond Verini, Dennis Balcombe, Phillip Webb, George Ballantine, Francis Batsoni, Leonard Kingston, Ned Hood, Cy Town, Alistair McFarlane (DWM 208)
 * Female Student - Maureen Race (DWM 208)
 * Prison Officers - Tony Jenkins, Richard Atherton, Les Clark, Gordon Stothard (DWM 208)
 * Medical Orderlies - Charles Pickess, Charles Finch (DWM 208)
 * UNIT Staff - Charles Marriott, Stuart Fell, Nick Hobbs (DWM 208)
 * Corpse of Cheng Teik - Francis Batsoni (DWM 208)
 * Photographers - Charles Marriott, Stuart Fell (DWM 208)
 * Police Superintendent - Paul Blomley (DWM 208)
 * Passer-by - Jim Delaney (DWM 208)
 * Voice of Mr Kerr and UNIT Transport - Lawrence Harrington (DWM 208)
 * Chinese Aide - Paul Tann (DWM 208)
 * Prisoners - Desmond Verini, Dennis Balcombe, Phillip Webb, George Ballantine, Francis Batsoni, Leonard Kingston, Ned Hood, Cy Town, Alistair McFarlane, Paul Blomley, Roger Marsden, Wolfgang Van Jergen, Michael Carter, Les Conrad, Les Clark, Roy Scammell, Mike Stevens, Marc Boyle, Terry Walsh, Richard Atherton, Timothy Combe (DWM 208), Valentino Musetti, Derek Martin, Max Diamond, Bob Blaine, Derek Chafer, Ricky Lancing, Johnny Clump, Pat Donahue, Michael Ely, Alan Chuntz, Billie Horrigan (TCH 16)
 * American Aide - Nick Hobbs (DWM 208)
 * The Master's Chauffeur - Francis Williams (DWM 208)
 * Police Inspector - Richard Atherton (DWM 208)
 * UNIT Corporal - Billie Horrigan (DWM 208)
 * UNIT Soldiers - Dennis Balcombe (DWM 208), Roger Marsden, Leslie Weeks, Tony Jenkins, Charles Marriott, Michael Carter, Ian Elliott, Robert Bald, John Griffiths (TCH 16)
 * Double for Barnham - Billie Horrigan (DWM 208)
 * Milkman - BG Heath (TCH 16)
 * Black Maria Drivers - Frank Bennett, BG Heath, Gary Gregory (TCH 16)
 * Van Driver - BG Heath (TCH 16)
 * UNIT Pilot - Ted Novak (TCH 16)
 * Dalek voice - Hayden Jones

Crew

 * Writer - Don Houghton
 * Title Music - Ron Grainer and BBC Radiophonic Workshop
 * Incidental Music - Dudley Simpson
 * Visual Effects - Jim Ward
 * Costumes - Bobi Bartlett
 * Make-up - Jan Harrison
 * Studio Lighting - Eric Monk
 * Sound - Chick Anthony
 * Special Sound - Brian Hodgson and BBC Radiophonic Workshop
 * Script Editor - Terrance Dicks
 * Designer - Ray London
 * Producer - Barry Letts
 * Director - Timothy Combe
 * Film Cameramen - Fred Hamilton, Max Samett
 * Film Editor - Howard Billingham
 * Action by HAVOC
 * Videotape Editors - Sam Upton, Roger Harvey

Uncredited crew

 * Effects Assistant - Dave Havard (INFO: The Mind of Evil)
 * Grams Operator - Gerry Burrows (INFO: The Mind of Evil)
 * Floor Assistant - John O'Shaunessy (INFO: The Mind of Evil)
 * Technical Manager - Graham Southcote (INFO: The Mind of Evil)
 * Vision Mixer - Mike Catherwood (INFO: The Mind of Evil)

Real-world cultural references

 * The Master listens to "The Devil's Triangle" by progressive rock group King Crimson, itself based on Gustav Holst's "Mars, the Bringer of War".

Food and beverages

 * The Chinese ambassador, Fu Peng, offers dried squid and stewed jellyfish to the Doctor and the Brigadier.
 * Jo gives Barnham a box of chocolates as a present.

The Doctor

 * The Doctor speaks fluent Hokkien (a dialect of Chinese).
 * When the Doctor is attacked by the Keller Machine he sees a Cyberman, a War Machine, a Zarbi, a Sensorite, Koquillion, an Ice Warrior (Slaar), and a Silurian, and hears a Dalek.
 * Aspirin is toxic to Time Lords.

Individuals

 * The Doctor says he once shared a cell in the Tower of London with Sir Walter Raleigh ("A very strange chap... kept going on about this new vegetable he'd discovered").
 * The Doctor says that he had a good enough relationship with Mao Tse-Tung that he was allowed to call the Chinese leader by his personal name, "Tse-Tung" (to understand the significance of this, the audience in 1971 would have needed to know that in Chinese names the surname is placed first, and the given name placed last).

Influences

 * A Clockwork Orange

Story notes

 * This story had the working titles The Pandora Machine, Man Hours, The Pandora Box and The Pandora's Box. Dave Houghton disliked the new title.
 * When the Doctor and Fu Peng are speaking Hokkien, a dialect of Chinese, English subtitles appear on screen — a first in Doctor Who history. English subtitles also appear in The Curse of Fenric, where they translate Russian language dialogue. In Remembrance of the Daleks, what appear to be Dalek subtitles appear (presumed to be a production unit joke). The dialect was chosen because it was the only one Pik-Sen Lim was comfortable teaching Jon Pertwee.
 * Lenny Vosper was named after script writer Don Houghton's agent, Margary Vosper (who also represented producer Barry Letts). Cheng Tiek was named after his father-in-law.
 * The Radio Times programme listing for episode one was accompanied by a black-and-white publicity photograph labelled "DOCTOR WHO in The Mind of Evil" showing the Doctor seated by the Keller Machine's control panel in the Process Theatre, with the accompanying caption "Jon Pertwee in a new story: 5.15". (original published text)
 * The production team jokingly dubbed the unconvincing Chinese dragon into which Captain Chin Lee appears to transform in episodes two and three "Puff the Magic Dragon", after the title character of the song by 1960s singing trio Peter, Paul and Mary. Director Timothy Combe subsequently used only brief shots of the dragon in the finished programme.
 * Tommy Duggan (Senator Alcott) appears in episode three only in the reprise, and is uncredited on-screen but credited in Radio Times.
 * William Marlowe (Mailer) appears in episode six only in the reprise, and is uncredited on-screen but credited in Radio Times.
 * Richard Franklin (Captain Mike Yates) is credited as "Captain Yates" in Radio Times for episodes five and six.
 * Matthew Walters (Main Gate Prisoner) is credited as "Main Gates Prisoner" in Radio Times.
 * At the beginning of episode one, the episode number caption remains on-screen after the opening title sequence ends, being superimposed onto the opening scene — the Doctor and Jo en route to HM Prison Stangmoor in Bessie — for a couple of seconds before it disappears. This was most probably a technical error.
 * With Mission to the Unknown, Doctor Who and the Silurians, The Dæmons, The Sea Devils, The Sontaran Experiment, Genesis of the Daleks, Midnight, The Lie of the Land, The Woman Who Fell to Earth and Ascension of the Cybermen, this is one of only eleven televised stories in the history of Doctor Who not to feature the Doctor's TARDIS. However, what appears to be the Master's TARDIS can be seen in the background near the end of episode six when the Master is on the phone to the Doctor, confirming that he has recovered his dematerialisation circuit.
 * The DVD recolourisation release of this serial features an additional set of credits for the restoration team that mimics the effects of the Keller Machine.
 * Stuart Humphryes, a.k.a. Babelcolour, manually recoloured episode one, as it lacked the necessary chroma-dot information to enable it to be restored to colour from black-and-white. (See Home video and audio releases below.)
 * In addition to playing Vosper on-screen, Hayden Jones provided the hallucinatory Dalek voice the Doctor hears while under attack from the Keller Machine.
 * Katy Manning named this as her favourite story.
 * The production team were loaned a real (but unprimed) Bloodhound 2 SAGW missile for use as the Thunderbolt from the 36th Heavy Air Defence Regiment out of Horseshoe Barracks in Shoeburyness, Essex, in addition to a number of troops who would play the Master's men (eight marines had also been made available for the Dover Castle sequences).
 * Kristopher Kum, who played the Chinese delegate Fu Peng, was cast at the last minute when the original actor, whose agent Kum was acting as, was considered by Timothy Combe to be unsuitable. Fortunately Kum had done some acting before turning to agency work, could also speak the right Chinese language, and hurriedly learned the lines.
 * Don Houghton's then wife Pik-Sen Lim played Captain Chin Lee. She was in the early stages of pregnancy at the time, so her costume was adjusted.
 * In a rarity for the early seventies, Chinese characters are played by Chinese actors. This was largely because Timothy Combe hated actors in yellowface, because he felt it was unrealistic.
 * The Master's henchmen were supposed to be wearing prison garbs, but they were played by soldiers in uniform, so Terrance Dicks added a line to episode five wherein the Master explained to Yates that the soldiers readying the Thunderbolt missile were "hired mercenaries in fake uniforms".
 * In the original script, the Brigadier was captured at Stangmoor Prison along with the Doctor and Jo; under the influence of the Master's hypnotism, he had the missile's route changed to enable the Master's men to hijack it.
 * Originally, one of the weapons used by the Keller Machine was the image of a Gorgon-like monster, which the Doctor eventually destroys by showing it its own reflection in the mirror of the missile transporter.
 * In the original script, Jo was subjected to the Keller Machine and her greatest fear turned out to be bats.
 * The script originally played up the tension between the United States and China, with Chin Lee attempting to frame an American delegate for Cheng Teik's murder.
 * Originally, the Keller Machine was simply going to be just a machine. During rewrites of the episodes, Terrance Dicks noticed that, due to plot holes that resulted from the editing process, it seemed to be acting like a self-willed, living thing and decided to go with that.
 * An early version of Episode Two's cliffhanger involved Chin Lee trying to blow up the peace conference using an explosive called kredalite.
 * The Master's pseudonym was originally Emil Dalbiac before the surname was changed to Keller; the first name was also sometimes spelt “Emile”.
 * The Keller Machine was originally called the Malusyphus box.
 * Corporal Bell was originally a man named Bates.
 * Costume designer Bobi Bartlett outsourced the assembly of the Stangmoor prison uniforms to a freelancer who had recently left the well-regarded Bermans & Nathans. The individual was then arrested for theft from his former employers, without completing his assignment. Bartlett was forced to visit him in prison in order to discover the location of the materials, which were then given to another costumier to finish the job.
 * The Doctor and Jo's escape via helicopter was added by Timothy Combe in order to add credibility to the scene, despite the substantial expense involved.
 * John Levene injured his leg during the Whitfield filming, after falling badly while being hauled out of the truck's cab by a stuntman playing one of the criminals.
 * Originally, another character pursued Chin Lee. When the actor fell ill, the scene was rewritten for Benton instead.
 * For the scene in which the Doctor speaks Hokkien Chinese, Jon Pertwee was coached by Pik-Sen Lim, although he still encountered sufficient difficulty that the lines had to be simplified.
 * Don Houghton intitially felt that the Keller Machine plot wasn't enough to sustain six episodes, so Pik-Sen Lim suggested a subplot involving intrigue at an international peace conference.
 * Timothy Combe had hoped to film inside a real prison, but was denied permission, so Dover Castle doubled as Stangmoor. The Doctor was given a line to explain that Stangmoor had originally been a medieval fortress, explaining why it looks like a castle.
 * Timothy Combe's children and Bobi Bartlett's son were the children on the playground in the scene where Chin Lee burned the purloined papers.
 * Andy Ho was originally cast as Fu Peng, but Timothy Combe wasn't satisfied with his performance, so Kristopher Kum was cast in his stead.
 * Katy Manning injured her back filming a fight scene when an extra fell against her.
 * The images of the Doctor's old enemies was originally going to include the Slyther, the Servo Robot and a Sensorite.

Ratings

 * Episode one - 6.1 million viewers
 * Episode two - 8.8 million viewers
 * Episode three - 7.5 million viewers
 * Episode four - 7.4 million viewers
 * Episode five - 7.6 million viewers
 * Episode six - 7.3 million viewers

Myths

 * The Doctor makes a comment in episode one which suggests he supports capital punishment. (His comment is ironic and suggests precisely the opposite.)

Filming locations

 * Cornwall Gardens, London (UNIT HQ Exterior)
 * Cornwall Gardens Walk, London (Benton mentally attacked when watching Chin Lee)
 * Dover Castle, Dover, Kent (Prison)
 * RAF Swingate, Dover, Kent (Yates on the phone)
 * Archer's Court Road, Whitfield, Kent (Prisoners prepare ambush)
 * Sky Charter Lmt, Kent (Missile prepared for launch)
 * BBC Television Centre (Studio 3 & 6), Shepherd's Bush, London

Production errors

 * In the office scene in episode four, a female sneeze from the studio is heard.
 * The hallway leading up to cell 7 (the cell where the Doctor and Jo are stashed at various points) has a different appearance, outside-looking-in than it does inside-looking-out.
 * When the Master's thugs throw the Doctor into the cell, the wall visibly shakes.

Continuity

 * The Master is still stranded on Earth when the story opens, in consequence of the Doctor having stolen the dematerialisation circuit from the Master's TARDIS in the previous serial. (TV: Terror of the Autons)
 * UNIT would subsequently provide the security for a second World Peace Conference. (TV: Day of the Daleks)
 * The Doctor mentions that he has recently witnessed an entire world consumed by fire. (TV: Inferno)
 * The Master uses gas grenades to knock out the prison guards but has a gas mask at the ready to protect himself. He would repeat this tactic in a later story. (TV: The Sound of Drums)
 * The Master plants a telepathic amplifier behind Captain Chin Lee's ear to control her mind. The Daleks would later utilise a human controlled remotely by a transmitter/receiver planted behind the victim's ear. (TV: Remembrance of the Daleks)
 * The journalist James Stevens was present as an observer at the demonstration of the Keller Process at Stangmoor Prison. After spending almost a year collating reports of agents provocateur known as "the Doctor" who had been involved in numerous unusual incidents, he finally saw one of them in person (he thought). He actually describes Jo: "[a] small, mousy looking woman with a pleasant face." (PROSE: Who Killed Kennedy)
 * A Northern Irish UNIT soldier named Francis Cleary was present for the riots at Stangmoor Prison and shot one of the inmates. (PROSE: Who Killed Kennedy)
 * Under the pseudonym "Victor Magister," the Master was charged with having caused the failure of the World Peace Conference, among other incidents, after being captured at Devil's End. Stevens notes that those terrorist activities were little remembered by most British people in 1996. (PROSE: Who Killed Kennedy)
 * In the Unbound Universe in which the Doctor's exile on Earth did not begin until 1997, the numerous deaths at the peace conference significantly damaged UNIT's reputation as an effective security endeavour. (AUDIO: Sympathy for the Devil)

DVD releases

 * This story was released on DVD on 3 June 2013 in the UK.

Special features

 * Audio commentary with actors Katy Manning (Jo Grant), Pik-Sen Lim (Chin Lee) and Fernanda Marlowe (Corporal Bell), director Timothy Combe, producer Barry Letts, script editor Terrance Dicks and stunt arranger Derek Ware. Moderated by Toby Hadoke
 * The Military Mind - A look at the making of the story. Featuring actors Nicholas Courtney, Pik-Sen Lim and Fernanda Marlowe, director Timothy Combe, producer Barry Letts and script editor Terrance Dicks
 * Now and Then - This feature visits the filming locations used in the story to see how they have changed over the years
 * Behind the Scenes: Television Center - Back in 1971, Presenter Norman Tozer visited Television Centre to find out what went on over 24 hours in the life of what was then an incredibly busy 'television factory'
 * 1971 Kellogg's Sugar Smacks promotion (DVD-ROM) - Doctor Who promotion in popular breakfast cereal
 * Radio Times Listings (DVD-ROM)
 * Photo Gallery
 * Programme Subtitles
 * Production Information Subtitles

Digital releases
This story is available:
 * for streaming through BritBox as part of Season 8 of Classic Doctor Who.

Video releases

 * This story was released as a double-cassette pack on VHS in 1998 in black-and-white — the only format in which it existed at the time. The only surviving colour footage from the story, approximately five minutes from the beginning of episode six, was included as a separate sequence at the end of the second tape.
 * Editing for the VHS release was completed by the Doctor Who Restoration Team.
 * According to the Restoration Team, episodes two to six had very strong colour signals embedded in the 16mm black-and-white film telerecordings, making it a good candidate for the colour recovery process developed from 2007–2009 which was used on episode three of Planet of the Daleks, part one of Invasion of the Dinosaurs, and episodes two to seven of The Ambassadors of Death. However, The Mind of Evil episode one was telerecorded with a notch filter present, which created a cleaner 16mm black-and-white film telerecording but rendered the colour signal lost forever. The Restoration Team has since used the chroma-dot technique to restore episodes two to six to colour. Episode one was recoloured manually by digital artist Stuart Humphryes, who worked from colour reference photos and the five episodes restored with the chroma-dot process.

Audio release
An audio version of the story was released on 9 February 2009, with linking narration provided by Richard Franklin.