Jack Hawkins

Detective Superintendent Tom Halliday

John Stratton

Detective Sergeant Ward

Dorothy Alison

Mary Halliday

Michael Brooke

Tony Halliday

Sam Kydd

Police Constable in Information Room

Glyn Houston

Detective Sergeant in 'Q' car

Richard Leech

Nightwatchman, Gilson

Newton Blick

Deputy Commander Harris

Geoffrey Keen

Chief Superintendent Jim Malcolm

Sydney Tafler

Stone

Peter Burton

Creasey

George Rose

Slob

Arthur Rigby

Detective Inspector at Chester

Ralph Truman

Colonel Blenkinsop

Ian Bannen

The Young Workman - Stanley James

Maureen Davis

The Young Workman's Wife - Mrs. James

John Warwick

Detective Inspector at Shipping Office

Joss Ambler

Cashier at Shipping Office