Shaw Taylor was the host of the 1972 pilot edition, being replaced by Edward Woodward - a panellist in the pilot - for the opening series in 1973. He was succeeded the following year by first season guest star Jon Pertwee, who chaired from 1974-78.

Some instalments (seemingly at least six from the first two seasons) were based on scripts originally written by Tony Shryane and Edward J. Mason for BBC Radio's 1954-61 series "Guilty Party".