James Mason

Richard Francis Heritage

Joyce Howard

Laura Verity

Tom Walls

Christopher Child

Phyllis Stanley

Lily Bernard

Edward Rigby

Mansel

Ronald Ward

Carter

David Farrar

Commander Lippinscott

Karl Stepanek

Riccardo

Betty Warren

Fay

Walter Crisham

Charlie

Jeanne De Casalis

Lady with Dog

Patricia Medina

Mary, Manicurist (as Pat Medina)

George Robey

Pawnbroker

Ronald Chesney

Max - Mouth Harmonica Player

Peggy Dexter

Bobby

Finlay Currie

Merchant Captain

Brefni O'Rorke

Detective Inspector Burrows

Eric Mason

Benson - Illusionist

Anthony Holles

Hotel Hairdresser

Ian Fleming

Kynaston Reeves

Naval Officer in Charge of Court Martial

Herbert Lomas

Van Driver

Percy Walsh

Police Sergeant

Terence de Marney

Code Expert

Charles Victor

Pub Owner

Robert Sansom

Petty Officer Bill Grant

Alvar Liddell

Boothby - Radio Announcer

Anthony Dawson

2nd Code Expert

Alf Goddard

One of Mansel's Tough Friends (uncredited)

David Keir

Henry (uncredited)

Jack Melford

Defence Lawyer at Court Martial (uncredited)

Hay Petrie

Waiter (uncredited)

Leonard Sharp

Bus Conductor (uncredited)

Dennis Wyndham

George the Barman (uncredited)