Maurice Colbourne, Ahmed Khalil and Elizabeth Cassidy are the only actors to appear in every episode, including Gangsters (1975). Alibe Parsons appeared in every episode except the pilot film.
The series was released on DVD through 2 Entertain/Cinema Club in April 2006. According to Philip Martin, the box set became a collectors' item after the company went bust. The series has to date not been re-issued and goes for high prices.
The theme music was an instrumental composed and performed by Dave Greenslade. It was released as a single with Sarah Grant's theme "Rubber Face, Lonely Eyes" as a B-side; the single was credited to Greenslade, even though the only performers on both tracks are Dave Greenslade and a session drummer. Greenslade recorded their own version of the song for their album Time and Tide.
At David Rose's request, for the second series, Dave Greenslade adapted the theme tune into a version with lyrics sung by Chris Farlowe.
Season two saw an increase in synthesiser music. Philip Martin said that this was Dave Greenslade and David Rose's idea. "He would orchestrate the music once the episodes were made. It was fairly novel to get a synthesiser doing music on a television programme at that time".