Margaret Rutherford
Grand Duchess Gloriana XIII
Ron Moody
Prime Minister Rupert Mountjoy
Bernard Cribbins
Vincent Mountjoy
David Kossoff
Professor Kokintz
June Ritchie
Cynthia
Terry-Thomas
Maurice Spender
John Le Mesurier
British Delegate
John Phillips
Bracewell - U.S. Delegate
Eric Barker
M.I.5 Man
Roddy McMillan
Benter
Tom Aldredge
Wendover
Michael Trubshawe
British Aide
Peter Sallis
Russian Delegate
Clive Dunn
Bandleader
Hugh Lloyd
Plumber
Graham Stark
Standard Bearer
Mario Fabrizi
Mario - the Valet
Jan Conrad
Russian Aide
John Bluthal
Von Neidell
Archie Duncan
U.S.A.F. General
Guy Deghy
Russian Scientist
Richard Marner
Russian Air Force General
Allan Cuthbertson
Member of Whitehall Conference
Robin Bailey
Member of Whitehall Conference
Gerald Andersen
Member of Whitehall Conference
Gordon Phillott
Civil Sergeant
John Wood
Countryman
George Chisholm
Wine Waiter
Vincent Ball
Pilot
Frank Duncan
News Announcer
Ed Bishop
American Astronaut
Bill Edwards
American Astronaut
Laurence Herder
Russian Astronaut
Harvey Hall
Russian Astronaut
Frankie Howerd
Self
Stringer Davis
1st Councillor (uncredited)
Lucy Griffiths
Lady-in-Waiting (uncredited)