The radio series (and the LP and TV versions) featured narration by comedy actor Peter Jones as "The Book". He was cast after a three-month search for an actor with sonorous, avuncular tones who sounded like Jones, after which the producers hired Jones himself. Following another actor dropping out of the production, Bill Wallis was called in at short notice to play two parts, Mr Prosser and Vogon Jeltz. One character appearing in the pilot who was dropped from subsequent incarnations of the story was Lady Cynthia, an aristocrat who helps demolish Dent's house, played by another ex-Cambridge Footlights actress, Jo Kendall.