"The Dæmons" began life as an audition scene for the companion Jo Grant. The audition sequence went on to be written into episode four. Producer Barry Letts was keen to write for the show and decided that a story dealing in black magic would be interesting as well as frightening. Script editor Terrance Dicks had reservations however, stating that people may view it as Satanist, and so it was reworked as strictly scientific with occultist themes. The Master was originally intended to worship the demon in a church set, standing on an altar. However, owing to fears that this might upset religious viewers, the scenes were reset in a crypt. This was subsequently revised again, and the crypt was called a cavern, although the set clearly resembled a church crypt. Letts initially intended to write the story himself but found himself short of time due to producership duties. His wife suggested a friend of hers, Robert Sloman, who was a playwright and journalist. Together they worked on the script in the evening after work. At the time, however, the BBC frowned upon production staff writing for their own series and so Letts and Sloman decided on the pseudonym Guy Leopold - Sloman's son and Letts' middle name respectively. The working title for this story was "The Demons", which was commissioned on 17 December 1970. The scripts were completed by mid-February 1971 and worked on by Dicks, who had barely completed work on them by the time the story went into pre-production in March.