Beryl Reid (Ruby Hubbard) previously appeared with George Cole in The Belles of St. Trinian's (1954)
The following actors from this episode previously appeared with Dennis Waterman in The Sweeney (1975). Bill Maynard (Barney Todd) appeared in Supersnout (1975). Fiona Mollison (Susan Hall) appeared in Sweeney 2 (1978). And Ivor Roberts (Jack Hodgson) appeared in Contact Breaker (1975)
Fiona Mollison (Susan Hall) later appeared with Dennis Waterman in 5 episodes of On the Up (1990). From Meeting Jane Webster (1991) to Stephanie (1992)
Whilst looking at story cards for plot ideas for the book, Beryl Reid's character Ruby Hubbard says "I know, American detective comes to London". This idea was used for real with the production of Dempsey and Makepeace the following year.