During production of season eleven, it was known 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.[1]Tom Baker was an out-of-work actor, working in construction at the time.[2][3] Baker had been a television and film actor, having major parts in several films including The Vault of Horror (1973) and as the main antagonist in The Golden Voyage of Sinbad the same year. He had written to Bill Slater, the Head of Serials at the BBC, asking for work.[3] Slater suggested Baker to Doctor Who producer Barry Letts who had been looking to fill the part.[2][3] Letts had been the producer of the series since the early Pertwee serials in 1970. He had seen Baker's work in The Golden Voyage of Sinbad and hired him for the part.[4] Baker would continue in his role as the Doctor for seven seasons, longer than any other actor to play the part.[5]
Elisabeth Sladen returned to play the role of companion Sarah Jane Smith throughout the season. Ian Marter joined the cast as Harry Sullivan. The character was created before Baker was cast; there had been discussion of casting an older actor as the Doctor, and so Harry was created as a younger character to handle the action scenes.[citation needed]
After Robot, all the serials in this season continue directly one after the other, tracing one single problematic voyage of the TARDIS crew. Despite the continuity, each serial is considered its own standalone story.
The season was initially formatted as the previous Pertwee season had been with three six-part stories and two four-part stories. To this end, the initial structure was to open with the four-part Robot and the four-part Space Station by Christopher Langley followed by three six-parters – Genesis of Terror (later retitled Genesis of the Daleks), Loch Ness, and another six-part story to be determined. Script editor Robert Holmes discussed with Philip Hinchcliffe the possibility of replacing the as-yet undecided six-parter with a four-part story and a two-parter, both with the same production team. The season structure later became two four-part stories (Robot and a replacement for Space Station, The Ark in Space), the new two-parter The Destructors (later retitled The Sontaran Experiment), the six-part Genesis of Terror, and a four-part version of Loch Ness (later retitled Terror of the Zygons and held over for season 13).[7] This decision made The Sontaran Experiment the first two-part story since Season 2'sThe Rescue. It was also the first to be shot entirely on location since Jon Pertwee's opening story Spearhead from Space in Season 7, and the first to be shot entirely on videotape instead of 16mm film, as was usual for location shooting.[8] As a means of saving money, The Ark in Space and Revenge of the Cybermen were shot on the same sets.
Sarah investigates the National Institute for Advanced Scientific Research, colloquially known as the "Think Tank". She finds that director Hilda Winters, her assistant Arnold Jellicoe, and former Think Tank member Professor J.P. Kettlewell are developing a robot, K1, out of living metal; and Winters and Jellicoe have secretly instructed K1 to steal international nuclear launch codes from the government. K1 discovers Sarah's presence and when UNIT arrives, the three conspirators and K1 escape with Sarah as their hostage. Winters sends a list of demands to the world governments, then orders Kettlewell to connect to the launch computers. Kettlewell hesitates, and Sarah and Harry attempt to escape. Winters orders K1 to stop them, but the robot inadvertently fires the disintegrator gun at Kettlewell; UNIT forces take Winters and Jellicoe away and K1 seeks out Sarah to protect her, an effect of Sarah's previous compassion; and then absorbs a disintegrator ray blast and grows to an enormous size. The Doctor returns, and uses a metal virus designed by Kettlewell to defeat the robot. Sarah is saddened by the loss of K1. The Doctor offers to cheer her up with a trip in the TARDIS, extending the invitation to Harry as well.
The Fourth Doctor, Sarah, and Harry are sent on a mission to Skaro to change the Dalek's history at their beginning to prevent them from becoming the dominant race. A war between the Thals and the Kaleds has left it nearly inhospitable. Sarah Jane is captured by the Thals; the Doctor and Harry by the Kaleds, and taken to a bunker where they meet the lead scientist Davros, who unveils his new invention, the Dalek. When halted from proceeding by the leadership, Davros covertly provides the Thal leaders a way to attack the Kaleds. Sarah is rescued; all Kaleds not in the bunker are killed. The Daleks attack the Thals. The survivors make their way to the bunker, and the Doctor goes inside. The Doctor rigs the Dalek incubation room with explosives, but hesitates to detonate them, questioning whether he has the right to make that decision. The Daleks return and exterminate the remaining Kaleds. A Dalek inadvertently sets off the explosives. The Doctor escapes before a bomb caves in the bunker, trapping Davros and the Daleks, who seemingly exterminate Davros. The Doctor considers his mission complete: out of the Daleks' evil, good will always arise to challenge them.
The Doctor, Harry and Sarah Jane find themselves on Space Station Nerva but millennia earlier when it was just a beacon for incoming and outgoing space ships, where a lethal infection is spreading through the crew.
Robot was written by Dicks, who cited King Kong as an influence for the serial.[11] Dicks incorporated several familiar elements from the Third Doctor's first story Spearhead from Space (1970), which helped the audience transition between actors.[12][13]The Ark in Space was written by Robert Holmes from a story by John Lucarotti that was considered unusable.[14][15] Letts and Dicks were eager to have Terry Nation return to write the Daleks, but initially found his script too similar to past Dalek adventures. They suggested that he write a Dalek origin story instead, which became Genesis of the Daleks.[16] However, under Hinchcliffe, the serial gained a darker tone.[16]
The sets of The Ark in Space were reused for Revenge of the Cybermen.[17]Genesis of the Daleks was the last serial of the season to be filmed, after Revenge of the Cybermen.[18] This took place in January and February 1975.[19]
Broadcast
The entire season was broadcast from 28 December 1974 to 10 May 1975.
The title sequence for Part One of The Ark in Space was tinted sepia as an experiment, but was not repeated for subsequent episodes.[20]
^ ab
Westthorp, Alex (24 April 2008). "Who could've been Who? An alternate history of Doctor Who". Den of Geek. London, England, UK: Dennis Publishing. Retrieved 18 January 2013. Eventually a suggestion by the wife of BBC drama head Bill Slater was followed up and the production team found the wild-eyed and naturally eccentric Tom Baker mixing cement on a building site.
^ abc
Westthorp, Alex (1 April 2010). "Top 10 Doctor Who producers: Part Two". Den of Geek. London, England, UK: Dennis Publishing. Retrieved 18 January 2013. Letts found casting a new Doctor more difficult, however, until a tip-off from his boss Bill Slater. An unemployed actor, then working on a building site, called Tom Baker had written to Slater asking for work. In, arguably, one of the best decisions ever made on Doctor Who, Letts cast Tom Baker as the fourth Doctor.
^
Rawson-Jones, Ben (14 October 2009). "A tribute to 'Doctor Who' legend Barry Letts". Digital Spy. New York City, New York, USA: Hearst Magazines UK. Retrieved 18 January 2013. Having seen unknown hod-carrier Baker in The Golden Voyage Of Sinbad, Letts took the goggle-eyed aspiring actor away from the building site and into the Tardis in 1974.
^Doctor Who: The Scripts – Tom Baker 1974/5. London: BBC Worldwide Limited. 2001. pp. 22–23. ISBN0563538155.
^Roberts, Steve (12 August 2006). "The Sontaran Experiment". Doctor Who Restoration Team. Archived from the original on 1 June 2012. Retrieved 15 April 2013.
