Glyn Houston

Detective Sergeant in 'Q' car

Richard Leech

Nightwatchman / Gilson

Newton Blick

Deputy Commander

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

Barry Keegan

Detective Constable in Hospital Ward

Alec McCowen

House Surgeon

Harry Locke

Secondhand Dealer

Nicholas Parsons

Police Constable Bates

Warwick Ashton

Newspaper Circulation Manager

Ursula Howells

Mrs. Elliot / Mrs. Gilson

David Davies

Welsh Police Constable

Julie Milton

Welsh Newsagent's Daughter

Meredith Edwards

Mr. Thomas

Harold Goodwin

Official at Somerset House

John Welsh

House Agent at Shepperton

Gillian Webb

Housewife at Shepperton

Maureen Delaney

Mrs. Stevens, the daily help

Jameson Clark

Detective Superintendent Ogilvie

William Mervyn

Manager of Festival Hall

Vincent Ball

P.C. at Hospital (uncredited)

Richard Davies

Detective (uncredited)

Frazer Hines

Urchin (uncredited)

Stratford Johns

Constable (uncredited)

David Lodge

Detective at Car Lot (uncredited)

Guy Standeven

Detective (uncredited)

Frederick Treves

Detective tailing Creasey (uncredited)

Peter Welch

CID Man (uncredited)

Martin Wyldeck

Officer in Criminal Records Department (uncredited)

Dennis Carnell

Edward Cast

Michael Collins

Fred Davis

Jack Dearlove

Robert Gregory

Fred Griffiths

Patrick Halpin

Aidan Harrington

George Holdcroft

Lindsay Hooper

Arthur Howell

Colin McKenzie

Jack McNaughton

Robert Moor

Fred Nicholas

John Paul

Roy Purcell

Charles Rayford

Anthony Richmond

Pat Ryan

Philip Stewart

Meadows White

John Wilder

Detective (uncredited)

Sonnie Wills