James Mason

Character: Cmdr. Max Easton

George Sanders

Character: Sir Charles Holland

Vera Miles

Character: Virginia Killain

Robert Flemyng

Character: Cmdr. John Larkin

Oliver Johnston

Character: Minister

William Kendall

Character: Tom

Duncan Lamont

Character: 1st Special Branch man Gregson

Harry Andrews

Character: Capt. Graham

Peter Barkworth

Character: Sub Lt. Brown

Rachel Gurney

Character: Clara Holland

Martin Stephens

Character: John Holland

Waveney Lee

Character: Marcia Holland

Charles Carson

Character: Robert Holland

Junia Crawford

Character: Susan

Henry B. Longhurst

Character: Club Member (as Henry Longhurst)

Roger Maxwell

Character: Club Member

Gerald Case

Character: Club Member

Donald Bisset

Character: Club Member

Desmond Roberts

Character: Club Member

Reginald Smith

Character: Club Steward

Rosemary Dorken

Character: WREN Officer

MacDonald Parke

Character: Jason Parrish (as Macdonald Parke)

Mavis Villiers

Character: Adele Parrish

Ernest Clark

Character: Cmdr. Bates

Alexander Archdale

Character: Local Doctor (uncredited)

Basil Dignam

Character: Lt. Cmdr. Evans at P.R.O. (uncredited)

Mabel Etherington

Character: Nightclub Patron (uncredited)

Gordon Harris

Character: 2nd Special Branch Man Jones (uncredited)

Barbara Hicks

Character: Miss Price (uncredited)

John Horsley

Character: 1st Editor (uncredited)

Frederick Kelsey

Character: Club Member (uncredited)

John Le Mesurier

Character: Head of the Admiralty (uncredited)

Ronald Leigh-Hunt

Character: 2nd Editor (uncredited)

Richard Marner

Character: Russian Officer Cornered by Max Easton (uncredited)

William Mervyn

Character: Capt. Balfour (uncredited)

Andre Mikhelson

Character: 2nd Russian Officer (uncredited)

John More

Character: American General at Embassy Party (uncredited)

Dickie Owen

Character: 2nd Policeman (uncredited)

Frederick Piper

Character: Hall Porter (uncredited)

Pat Ryan

Character: Nightclub Patron (uncredited)

Stanley Zevic

Character: 1st Russian Officer (uncredited)