The brutal nature of the war between the Kaleds and Thals was inspired by Things to Come (1936). Terry Nation also decided to play up the Nazi allusions which, he now realised, had influenced his original conception of the Daleks.
Michael Wisher prepared for his masked role of Davros by wearing a paper bag over his head during rehearsals, to help him convey much of the emotion of the part purely through dialogue. Wisher, a heavy smoker, put two holes in the top of the bag so he could smoke underneath it in rehearsals.
Mary Whitehouse of the National Viewers and Listeners' Association famously complained to the BBC about this serial, saying it was "teatime brutality for tots...this series has moved from fantasy to real-life violence with cruelty, corpses, poison gas and Nazi-type stormtroopers, not to mention revolting experiments in human genetics".
Katy Manning has said she thinks the Daleks lost their menace beginning with this story because of the introduction of Davros. She said "suddenly it's half a bloke in there... There's nothing human about a Dalek". Although Katy Manning criticised this serial for the introduction of Davros, former producer Barry Letts called this "Terry Nation's masterpiece, even better than the very first Dalek story".
Davros attracted the attention of BBC prosthetics designer John Friedlander who agreed to come off another show to make Davros' mask. The latex mask was moulded to Michael Wisher's face by make-up artist Sylvia James. Wisher could even eat while wearing the mask. Regular latex instead of the more mouldable foam latex was used because the latter was too expensive.
Producer Philip Hinchcliffe didn't want to do a story featuring Daleks but inherited this script from outgoing producer Barry Letts. However, Hinchcliffe has since said that this turned out to be a very good story and a successful production that he is proud of. Having been landed with a Dalek story he didn't really want, he impressed upon director David Maloney his desire to give it a different feel from previous Dalek stories and to make them more compelling than in some of their previous appearances.
When planning stories for season 12, outgoing producer Barry Letts and script editor Terrance Dicks felt that it was time for Terry Nation to return to the series and write another Dalek adventure. Letts and Dicks enjoyed the script Nation sent in, but found it too "reminiscent" of previous Dalek stories. Letts suggested to Nation that he could write a story about the genesis of the Daleks, hence the eventual title. The stories lined up for the season were handed over by Letts and Dicks to their successors, Philip Hinchcliffe and Robert Holmes, with whom the story gained a darker tone. Hinchcliffe and Holmes were not fans of the Daleks, feeling they had been used too often already, but Letts and Dicks were convinced they would be a guaranteed ratings draw for the new Doctor's first season.
In a 2006 interview, Terrance Dicks said that he does not believe the story would have been much different if he and Barry Letts were in charge, though he remarked he would have added some lighter moments to soften the "grim" tone.
The character of Davros was designed by Terry Nation to have created the Daleks in his image, and to also be a "spokesperson" for the Daleks as he felt it was "boring" listening to Daleks giving speeches.
Nyder wears an Iron Cross medal in this episode only. Although the Kaled Elite were supposed to be reminiscent of the Nazis, it was decided during filming that the Iron Cross was too blatant a reference, so that element of his costume was eliminated for the rest of the story.
Producer Philip Hinchcliffe was very pleased with David Maloney's work on this serial and he became his most prolific director, working on three further serials for him. Hinchcliffe later said Maloney and Douglas Camfield were his two favourite directors.