George Cole

George Archibald Potts

Oskar Homolka

Zekov

Nadia Gray

Tania

Wilfrid Hyde-White

Sir Hubert Wells

Richard Wattis

Barnes

Irene Handl

Mrs. Tidmarsh

Christopher Lee

Russian Agent (uncredited)

Frederick Leister

Prime Minister

Frederick Valk

Rakov

Geoffrey Sumner

Pike

Ronald Adam

Barworth Controller

Edwin Styles

Barworth Superintendent

Kynaston Reeves

Barworth Director

Michael Medwin

Smedley

Henry Hewitt

Minister of Health

Tim Turner

1st Reporter

Gibb McLaughlin

Schoolmaster

Hal Osmond

Jersey Waiter

Charles Goldner

Gaston

Ronnie Stevens

Aubrey

Eleanor Summerfield

Cecilia

Ina De La Haye

Madame

David Hurst

Deutsch

Olaf Pooley

Roblettski

Terence Alexander

2nd M.V.D.

Richard Marner

Russian Sentry

Martin Boddey

Russian Security Officer

Gerard Heinz

Russian Director of Plant

Victor Maddern

British N.C.O.

Willoughby Gray

British Officer

Anton Diffring

Border Police GDR (uncredited)