Spencer Banks (Rev Simon Randall) played a character called Simon Randall in the 1970 children's UKTV series Timeslip (1970). His co-star in that series was Cheryl Burfield, playing his wife in this film. Lesley Scoble (Karen) was another castmember from the show, where she played Alpha 17. The Harrimans are also forenamed Frank and Jean, after the Skinners from the show. (Writer Steve Hardy is a fan of the ATV show.)
Steve Hardy: The screenplay writer cameos as the heavy that knocks Victor Stewart out when he visits the Mayor's office.