Working titles for this story included The Ghost Hunters and Years of Doom. As originally written, the serial revolved around the Ogrons instead of the Daleks. It was planned to bring the Daleks back at the end of the season, in a serial called The Daleks in London by Robert Sloman. This plan was dropped when the production staff realised that the show would not have a hook to entice viewers (after the Third Doctor's introduction in Season 7 and that of the Master in Season 8), and Sloman's serial was allegedly shaping up to be too similar to "The Dalek Invasion of Earth". Instead, writer Louis Marks was asked to alter his serial to include the Daleks. Osterley Park was originally proposed as the setting and location for "Day of the Daleks". The name was changed to Auderly House in the finished programme and renamed Austerly House in the novelisation.