Three Laws of Robotics. The villain of the story is named Taren Capel, which is a reference to Karel Čapek, who is credited with first coining the word "robot". Uvanov's name is a reference to Isaac Asimov, while Poul is a reference to the science fiction writer Poul Anderson. The script several times refers to Robophobia (the irrational fear of robots) as 'Grimwade's Syndrome', an inside joke reference to Peter Grimwade, a production assistant who directed some of the filmed scenes in the episode. Grimwade had frequently lamented that he was always working on material involving robots. The sandminer was derived from Dune. Cast notes Russell Hunter was allegedly cast against the intention of the script, which implied that Commander Uvanov should be a physically imposing man, much in the mould of an eighteenth-century sailing master. David Collings, who plays Poul, previously appeared as Vorus in Revenge of the Cybermen and would later appear as Mawdryn in Mawdryn Undead as well as an alternative incarnation of the Doctor in the Big Finish Productions' Doctor Who Unbound audio drama Full Fathom Five. Pamela Salem, who plays Toos, had provided voice work in the preceding story The Face of Evil and would later appear as Professor Rachel Jensen in Remembrance of the Daleks. Salem had been one of the actresses considered for the part of Leela. David Bailie went on to play the Celestial Toymaker in the audio plays The Nightmare Fair and Solitaire. Broadcast and reception Episodes 1 & 2 and Episodes 3 & 4 were combined into two 50-minute episodes for repeat on 31 December 1977 and 1 January 1978, reaching 10.0 and 7.0 million viewers respectively. Paul Cornell, Martin Day, and Keith Topping, in The Discontinuity Guide (1995), called the script "one of the best ever" and praised how it was enhanced by the design, acting, and direction. In The Television Companion (1998), David J. Howe and Stephen James Walker expressed similar praise, describing it as a "true classic" and praising the Art Deco design. In 2010, Mark Braxton of Radio Times observed a few production errors but overall praised the design and voices of the robots and the score. He also called the story "extraordinary", despite there being a coldness between Baker and Jameson that made it to the screen. DVD Talks Ian Jane was less positive, giving the story three and a half out of five stars.