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
Ernest Jay
— Professor Layton
Michael Medwin
— Smedley
Henry Hewitt
— Minister of Health
Walter Horsbrugh
— 1st Cabinet Minister
Anthony Shaw
— 2nd Cabinet Minister
Tim Turner
— 1st Reporter
Gibb McLaughlin
— Schoolmaster
Michael Balfour
— Jersey Sailor
Hal Osmond
— Jersey Waiter
Charles Goldner
— Gaston
Ronnie Stevens
— Aubrey
Eleanor Summerfield
— Cecilia
Phyllis Morris
— Mrs. Tweedy
Myrtle Reed
— Jersey Air Hostess
Ina De La Haye
— Madame
David Hurst
— Deutsch
Bernard Rebel
— Trubiev