Production
As the Doctor was transitioning from the third to the fourth incarnations, changes were also occurring in the production department of Doctor Who. Barry Letts, who had been the producer since the second Jon Pertwee serial in 1970, was leaving the series, but would stay on to cast the part of the new Doctor as well as produce this debut serial. Letts would be succeeded for the next story by Philip Hinchcliffe, who trailed him on this story.
Terrance Dicks, who had worked on the series as a script editor since 1968, [3] was also leaving, to be replaced by Robert Holmes. Holmes had been a writer for the show since season six and penned four stories in Pertwee's era, including Spearhead from Space (1970), the Third Doctor's first serial. Though Dicks was leaving as script editor, he would still be involved with the series as an occasional writer. Having previously helped write the serials The Seeds of Death and The War Games (both 1969), Dicks would write the first story for the incoming Fourth Doctor.
The K1 robot costume was designed by one of the series' regular costume designers at the time, James Acheson, and built by sculptor [4] Allister Bowtell. [5]
Conception and writing
Terrance Dicks stated that a major influence for this story was King Kong (1933). [6] The initial script was written before Tom Baker had been cast as the Fourth Doctor, and there was some discussion of returning to an older actor. This would have required a younger character to handle the action scenes, so the character of Harry Sullivan was created. This was Sullivan's debut story, but he had been mentioned in the final episode of the preceding serial, when the Brigadier telephoned him, requesting medical help for the Doctor.
Dicks included a number of elements from Spearhead from Space: the Doctor being disorientated after regeneration, going to hospital to recover, changing costume as a result of escaping from hospital in a hospital gown, viewing himself in a mirror to see his new face, and storing the TARDIS key in his shoe. [7] These elements helped the audience with the transition between actors. [5] [8] [9]
Casting
It was known beforehand that Jon Pertwee would be leaving his role as the Third Doctor and that a new Fourth Doctor would need to be cast for the part. [10] Tom Baker had previously had major parts in several films, including Nicholas and Alexandra (1971) and The Vault of Horror (1973), but had found himself unemployed as an actor and working in construction at the time. [11] [12] He had written to Bill Slater, the Head of Serials at the BBC, asking for work. [12] Slater suggested Baker to Doctor Who producer Barry Letts, who had been looking to fill the part. [11] [12] Letts saw Baker's work in The Golden Voyage of Sinbad (1973) and hired him. [13] Baker would continue in his role as the Doctor for seven seasons, longer than any other actor. [14]
Nicholas Courtney and John Levene reprised their roles as Brigadier Lethbridge-Stewart and Sergeant Benton respectively. [1] Levene had started his role with the Second Doctor story The Invasion (1968) as a member of the military organisation UNIT (the United Nations Intelligence Taskforce). Courtney started earlier in the same year in The Web of Fear , with his character's rank being a colonel. They, along with Sladen, would be the transition cast to carry through from the Third Doctor to the Fourth Doctor, though this would be the only UNIT story for the twelfth season. The Earth-based stories involving UNIT, which had regularly featured in the Third Doctor's period, were introduced partly as an effort to reduce production costs when the series moved into colour by Peter Bryant and Derrick Sherwin, the show's previous producer and script editor, as well as to base the series more on The Quatermass Experiment (1953).
Edward Burnham portrays Professor Kettlewell, the wild-haired, bespectacled boffin who creates the titular K1 robot. [1] Along with Courtney and Levene, Burnham had also appeared in The Invasion, where he played another scientist, Professor Watkins. The part of the K1 robot is played by Michael Kilgarriff [1] who had played another robotic part in The Tomb of the Cybermen (1967), the Cyberman Controller. Patricia Maynard is cast in the part of Miss Hilda Winters, the director of the National Institute for Advanced Scientific Research. [1] Miss Winters' assistant, Arnold Jellicoe, is played by Alec Linstead. [1] Linstead had played the part of Sergeant Osgood—a member of the technical staff at UNIT—in The Dæmons (1971).
Recording
This was the first Doctor Who serial to have its location material shot entirely on videotape using outside broadcasting facilities, as opposed to the more usual BBC television drama practice of the time of shooting studio interiors on videotape and location exteriors on 16 mm film. This was due to the large number of video effects involving the eponymous robot required in exterior scenes (shot at the then BBC Engineering Training Department at Wood Norton, Worcestershire [1] [15] ), which were easier and more convincing to marry to videotape than to film. The team had learned that lesson during the previous season's Invasion of the Dinosaurs . The Wood Norton facility was chosen for location shooting because it had an underground bunker, which director Christopher Barry felt would be suitable for the entrance to the underground complex in the story; however, they were refused permission to shoot in that area. [15]
