Jack Hawkins
Role: Supt Tom Halliday
John Stratton
Role: Sergeant Ward
Dorothy Alison
Role: Mary Halliday
Michael Brooke
Role: Tony Halliday
Sam Kydd
Role: Police Constable in Information Room
Glyn Houston
Role: Detective Sergeant in 'Q' car
Richard Leech
Role: Nightwatchman / Gilson
Newton Blick
Role: Deputy Commander
Geoffrey Keen
Role: Chief Superintendent Jim Malcolm
Peter Burton
Role: Creasey
Arthur Rigby
Role: Detective Inspector at Chester
Ralph Truman
Role: Colonel Blenkinsop
Ian Bannen
Role: The Young Workman - Stanley James
Maureen Davis
Role: The Young Workman's Wife - Mrs. James
John Warwick
Role: Detective Inspector at Shipping Office
Joss Ambler
Role: Cashier at Shipping Office
Barry Keegan
Role: Detective Constable in Hospital Ward
Alec McCowen
Role: House Surgeon
Harry Locke
Role: Secondhand Dealer
Nicholas Parsons
Role: Police Constable Bates
Warwick Ashton
Role: Newspaper Circulation Manager
Ursula Howells
Role: Mrs. Elliot / Mrs. Gilson
David Davies
Role: Welsh Police Constable
Julie Milton
Role: Welsh Newsagent's Daughter
Meredith Edwards
Role: Mr. Thomas
Harold Goodwin
Role: Official at Somerset House
John Welsh
Role: House Agent at Shepperton
Gillian Webb
Role: Housewife at Shepperton
Maureen Delaney
Role: Mrs. Stevens, the daily help
Jameson Clark
Role: Detective Superintendent Ogilvie
William Mervyn
Role: Manager of Festival Hall
Vincent Ball
Role: P.C. at Hospital (uncredited)
Richard Davies
Role: Detective (uncredited)
Frazer Hines
Role: Urchin (uncredited)
Stratford Johns
Role: Constable (uncredited)
David Lodge
Role: Detective at Car Lot (uncredited)
Guy Standeven
Role: Detective (uncredited)
Frederick Treves
Role: Detective tailing Creasey (uncredited)
Peter Welch
Role: CID Man (uncredited)
Martin Wyldeck
Role: Officer in Criminal Records Department (uncredited)
John Wilder
Role: Detective (uncredited)
