Directed by Charles Frend | Starring: Jack Hawkins, John Stratton, Dorothy Alison, Michael Brooke

Scotland Yard detectives attempt to solve a spate of safe robberies across England beginning with clues found at the latest burglary in London. The film is notable for using a police procedural style made popular by Ealing in their 1950 film The Blue Lamp. It is known in the US as The Third Key.