The success of this movie, in spite of its controversial themes, encouraged Janet Green to write Victim (1961), and Basil Dearden to direct it.
Paul Slade's car is a 1949 Jaguar XK120 open two-seater. 7,606 were built in both left- and right-hand drive from 1948 to 1954. In excellent condition, this car could bring in well over $100,000 at auction in 2020.
The detectives are driven around in a 1957 Wolsely 6/90 Series III. This same car can be seen in Again the Ringer (1965), Murder Most Foul (1964), Danger Man: The Sanctuary (1960), and The Devil's Daffodil (1961).