A mismatched collection of conscripted civilians find training tough under Lieutenant Jim Perry and Sergeant Ned Fletcher when they are called up to replace an infantry battalion that had suffered casualties at Dunkirk.

P.C. George Dixon (Warner) is a long-serving traditional copper who is due to retire shortly. He takes a new recruit under his aegis and introduces him to the easy-going night beat. Dixon is a classic ordinary hero but also anachronistic, unprepared and unable to answer the violence of the 1950s.