Leslie Banks
— Taylor
Michael Redgrave
— Russian
Will Hay
— Skipper
John Mills
— Tom
Bernard Miles
— Royal Navy Mate
Michael Rennie
— George
Frank Cellier
— Schneider
Robert Morley
— Von Geiselbrecht
Alfred Drayton
— Direktor
Marius Goring
— German Propaganda Officer
Austin Trevor
— U-boat Captain
Albert Lieven
— Gunter
Leif Konow
— Dane
John Stuart
— Royal Navy: Naval Officer
Morland Graham
— Civil Service
John Boxer
— Press
Cyril Chamberlain
— Press
Elliott Mason
— German: German Stationmistress
George Merritt
— German: German Shelter Marshal
Bernard Rebel
— Quisling
George Woodbridge
— Quisling
Ronald Adam
— German businessman (uncredited)
Mark Daly
— Driver (uncredited)
Thora Hird
— German barmaid (uncredited)
Frederick Piper
— Malta official (uncredited)
Ronald Shiner
— Shipping clerk (uncredited)
Manning Whiley
— Naval officer (uncredited)
Michael Wilding
— Captain (uncredited)
John Williams
— Voice over (uncredited)