NB: This episode no longer exists in the archives, nor is there a full set of telesnaps. Representative images are therefore used to illustrate it.
As Katarina goes to check on the airlock door she is seized by the convict Kirksen, who drags her inside and seals them both in...
The desperate man insists that they change course. He cannot go to Earth, and demands to be taken to Kembel instead. Bret argues that they cannot jeopardise their mission for the sake of a single individual, whilst Steven insists they do everything in their power to free Katarina. The Doctor is forced to agree that they should change course for Kembel - though only to give them time to work out some other plan.
Realising that the fate of millions depends upon the success of the Doctor's mission, and recalling the prophecy of her imminent death, the young Trojan elects to open the outer airlock door.
She and Kirksen are sucked out into space...
Steven and Bret are horrified at what has just happened, but the Doctor has them focus on their mission. Katarina has sacrificed herself so that they might have a better chance of success, so they must not let her death be in vain.
On Kembel, the Dalek pursuit ship has reported its failure on Desperus. Despite being in a position to resume its chase, the Supreme orders that the vessel be destroyed. Failure is not to be tolerated.
Trantis begins to openly criticise the Daleks for putting so much trust in Mavic Chen.
He, meanwhile, is back on Earth and is working with his deputy Karlton to identify the agents who have interfered with their plans - for Karlton is fully involved in his superior's treason.
He dismisses his deputy's claims that Trantis will be made the chief ally of the Daleks. It is a role he plans to assume himself.
Chen is unhappy that his underling failed to stop the investigations by first Marc Cory and then Vyon and Gantry. He insists that the occupants of the Spar be killed immediately on landing.
All agents have been recalled, and Chen approves of Karlton's decision to place agent Kingdom in charge of the operation.
The Spar approaches Earth, and Bret informs the others that he plans to make for a scientific research centre well away from the main landing area, where a friend named Daxtar is based. He should be able to help them.
Chen sends an update to the Supreme, adding the deliberate disinformation that Bret's allies have been identified as coming from Trantis' galaxy.
Daxtar is at first difficult to convince of Chen's treason with the Daleks, but then he offers to assist them. The Doctor suddenly accuses him of being part of the conspiracy. he had mentioned the Taranium Core, when no-one had said anything about it containing that mineral. Realising that his friend is another traitor, he guns shoots him dead.
The Spar was damaged on landing so they cannot return to it, but Space Security agents are closing in. Kingdom forces scientist Borkar to accept her fellow agents taking over the complex.
The Doctor and Steven run deeper into the research centre whilst Bret holds back to win them time to escape, hoping to convince his fellow agents that they are being manipulated.
He is pleased to see Kingdom - Sara Kingdom - but she guns him down.
She orders that the other two criminals are to be shot dead - coldly advising her colleague to aim for the head...
Next Episode: Counter Plot
Written by: Terry Nation
Recorded: Friday 12th November 1965 - Television Studio TC3
First broadcast: 5:50pm, Saturday 4th December 1965
Ratings: 9.5 million / AI 51
Designer: Barry Newbery
Director: Douglas Camfield
Additional cast: Jean Marsh (Sara Kingdom), Maurice Browning (Karlton), Roger Avon (Daxtar), James Hall (Borkar).
For Adrienne Hill, her first work on Doctor Who was to attend Ealing Film Studios on Monday 27th September to film her death scene.
It had become apparent very quickly that the character of Katarina, deriving from the ancient past, would be difficult to write for. She would need even the most basic technological concepts explaining to her - like switching on an electric light bulb.
It was decided to quickly write her out of the series, and John Wiles and Donald Tosh hit upon the idea to have her die. This would wake up the audience, who might have become complacent about the dangers faced by the Doctor and his companions. Especially when they were up against the Daleks, no-one was safe.
So Hill went to Ealing along with Doug Sheldon, who was playing Kirksen. They were filmed in slow motion on a trampoline, set against a star-scape back projection. The camera filmed up through the weave of the trampoline surface, which disappeared due to the nature of the focus.
Hill and Sheldon appeared to slowly float and revolve in the finished footage.
When The Traitors was broadcast on 4th December, one viewer who was especially interested in this sequence was film director Stanley Kubrick. He was in England working on his adaptation of Arthur C Clarke's sci-fi short story The Sentinel, which would become 2001: A Space Odyssey, and was keen to know how Camfield had handled the space-set scenes.
His office rang the Doctor Who team the following Monday to make enquiries.
As one door closes, another opens, and joining the series this week is Jean Marsh, who had previously played Princess Joanna in two episodes of The Crusade for Camfield the year before.
Sara would take Katarina's place for the remainder of the story, and was very much a creation of Terry Nation's. He would later use the character in his attempted Dalek spin-off series, as well as featuring in some stories in the tie-in Dalek books of the mid-60's.
The character was very much inspired by Cathy Gale of The Avengers, who frequently employed her martial arts skills. She could be feminine whilst still being a strong, independent individual.
Her name was one of the things which Nation refused to allow to be changed by Tosh or Camfield.
Sara certainly doesn't come across as companion material in her opening scenes. She's cold hearted, and kills Bret, who we've come to like over the last four week.
Viewers at the time might have only just started to get over the shock of Katarina's sacrifice when they're confronted by the death of another of the Doctor's friends.
It's an extremely dark instalment - entering territory which Wiles and Tosh very much wished to take the series.
The original conception for this episode was that the Spar would land in New Washington, where agent Brett Walton had a friend named Tom who might help them. Despite being a traitor, Tom couldn't bring himself to hand his friend over to the authorities and so had him and the others transported to an alien planet by rocket to evade capture. The Daleks then killed Tom for his failure to capture them.
The dead Katarina was to have been shown as a photo-caption only, with her hair streaming out and a "Mona Lisa" smile on her face. Karlton was originally Carlton, and Sara Kingdom was described as Agent 505. She was intended to be Bret's lover - softened to his sister in the next episode (which only serves to make her personal killing of him even more shocking).
After being named Tom, Daxtar became Dexter for a while. Chen and Karlton discussed the Daleks' plan to only allow a special group of 50 individual humans to survive after they conquered the Solar System. They would be part of the select few, but Kingdom wasn't to be spared.
Bret wasn't killed instantly, and he continued to try to convince Sara of Chen's treachery as he died.
The cliff-hanger was to have been Sara confronting the Doctor and Steven in the silo of the rocket which would take them to the alien planet of the next instalment.
Marsh joined the cast for rehearsals on Monday 8th November, and was found to be a terrible giggler.
This infuriated John Wiles.
At one point on the day of recording she broke a control on the TARDIS console and laughed so much that she was banished from the studio until she could compose herself.
The closing section of the previous episode was remounted.
Chen's office set had a large screen for back projection - including a "3-D" image of Bret, Courtney having been filmed with multiple cameras against black drapes on Friday 8th October.
Daxtar's laboratory set included a wall which had moving light patterns projected on to it, using Mirrorlon (the flexible mirrored material which would later be used to represent the effects of Ice Warrior sonic weaponry).
William Hartnell was feeling unwell and unhappy throughout this period, and could be more irritable than usual because of this. Around this time he upset his dresser, resulting in a temporary walk-out by the department in protest. Earlier in the week, Hartnell's favourite chair had gone missing from the rehearsal room, and Wiles had to explain that it was being used by another production.
A code was devised: "Better phone the designer" to signify that Wiles was required without alerting Hartnell that his producer had been summoned.
Due to the poor personal and working relationship between star and producer, it was Tosh who tended to be called upon to mediate and placate.
This was Adrienne Hill's final appearance in Doctor Who. Despite her short tenure she is considered a bona fide companion, having appeared in more than one story and also travelled in the TARDIS (two of the conditions which fans often use to define the role). She featured on Children in Need in 1985, when a host of stars of the show emerged from the TARDIS to hand over a cheque. A convention appearance, in the company of Carole Ann Ford, Jacqueline Hill and Michael Craze, is available on the Season 2 Blu-ray box set.
Sadly, she passed away in October 1997, aged only 60. Her final acting role was in a New Zealand TV series, which was broadcast posthumously.
- The ratings suffer a 0.8 million drop on the previous episode. We are now into December, so Christmas shopping and festive events may be having an impact. There's also a one point drop in the appreciation figure.
- The sequence depicting the death of Katarina, up to the point where she opens the outer airlock door, survives once again through inclusion in an edition of Blue Peter.
- Adrienne Hill was already working on soap opera The Dales when she made this episode.
- There was one trimmed scene from this episode, in which Chen realised that Bret was going to make contact with Daxtar.
- Like Marsh, Roger Avon had also featured in The Crusade - playing Saphadin, who just happened to hold a torch for her character.
- James Hall had featured in The Reign of Terror.
- Our old friend the Morok Freezing Machine makes another appearance as an piece of equipment in Daxtar's lab (above).
- One item of adverse publicity was an article in the Daily Mirror tabloid, wherein a Mrs Clark of Andover explained why she was banning the programme from her home, despite the fact her children enjoyed it. She was upset with the deaths in this episode - particularly Katarina's - and was arguing that the series be moved to a 7pm time slot.
- The newspapers covered Jean Marsh's arrival in the series on the day of broadcast, illustrated with images taken on the day of recording the seventh episode, The Feast of Steven. The Cathy Gale / Avengers connection was stressed.