George Archibald Potts

George Cole

Zekov

Oscar Homolka

Tania

Nadia Gray

Rakov

Frederick Valk

Sir Hubert Wells

Wilfrid Hyde-White

Pike

Geoffrey Sumner

Barnes

Richard Wattis

Mrs. Tidmarsh

Irene Handl

Russian Agent (uncredited)

Christopher Lee

Barworth Controller

Ronald Adam

Barworth Superintendent

Edwin Styles

Prime Minister

Frederick Leister

Barworth Director

Kynaston Reeves

Prof. Layton

Ernest Jay

Smedley

Michael Medwin

Minister of Health

Henry Hewitt

Cabinet Minister #1

Walter Horsbrugh

Cabinet Minister #2

Anthony Shaw

1st Reporter

Tim Turner

Schoolmaster

Gibb McLaughlin

Jersey Sailor

Michael Balfour

Jersey Waiter

Hal Osmond

Prof. Deutsch

David Hurst

Gaston

Charles Goldner

Minor

Terry Alexander

Director

Gerard Heinz

Aubrey

Ronnie Stevens

Prof. Roblettski

Olaf Pooley

Cecilia

Eleanor Summerfield

Mrs. Tweedy

Phyllis Morris

Jersey Air Hostess

Myrtle Reed

Madame

Ina De La Haye

Prof. Trubiev

Bernard Rebel

1st M.V.D.

Guido Lorraine

Russian Sentry

Richard Marner

Russian Security Officer

Martin Boddey

Russian Doctor

Fred Berger

British N.C.O.

Victor Maddern

Reed de Rouen

2nd U.S. Soldier

Johnny Catcher

British Officer

Willoughby Gray

1st U.S. Soldier

Reed De Rouen

Josef Stalin

Stanislaus Zienciakiewicz

Border Police GDR (uncredited)

Anton Diffring