The last film made at England’s Ealing Studios before its sale to the BBC, Charles Frend’s The Long Arm (US: The Third Key) is a police procedural noir that emphasizes clues and deduction over thrills and violence. Jack Hawkins stars as Scotland Yard Superintendent Tom Halliday, called in to lead the investigation of a pair of robberies that share an odd characteristic: in both incidents, a safe was robbed by someone who had a key, despite all known keys being accounted for. Following a trail of clues that leads through a fake nightwatchman, a safe manufacturer, a locksmith, an insurance company, an auto chop shop, a fatal hit and run, and a man who’s been dead for two years, Halliday and his new, younger partner Ward (John Stratton) discover there’s a fixed number of identical safes in the country and make it their business to track each one down, culminating in a stakeout at Royal Festival Hall. Dorothy Alison is inconsequential in the role of Halliday’s wife Mary, and the always reliable Geoffrey Keen plays Halliday’s boss, Chief Superintendent Jim Malcolm, who suspects the thefts are inside jobs. Production designer Carrick turns the Ealing studio sets into wet, foggy London streets, and cinematographer Dines’s technical proficiency brings little attention to itself aside from an occasional subjective camera or a moment shot in deep focus.