Margaret Rutherford
Grand Duchess Gloriana XIII
Acting
Ron Moody
Prime Minister Rupert Mountjoy
Acting
Bernard Cribbins
Vincent Mountjoy
Acting
David Kossoff
Professor Kokintz
Acting
Terry-Thomas
Maurice Spender
Acting
June Ritchie
Cynthia
Acting
John Le Mesurier
British Delegate
Acting
John Phillips
Bracewell - U.S. Delegate
Acting
Eric Barker
M.I.5. Man
Acting
Roddy McMillan
Benter
Acting
Tom Aldredge
Wendover
Acting
Michael Trubshawe
British Aide
Acting
Peter Sallis
Russian Delegate
Acting
Clive Dunn
Bandleader
Acting
Hugh Lloyd
Plumber
Acting
Graham Stark
Standard Bearer
Acting
Mario Fabrizi
Mario - the Valet
Acting
Jan Conrad
Russian Aide
Acting
John Bluthal
Von Neidel (as John Bluthall)
Acting
Archie Duncan
U.S.A.F. General
Acting
Guy Deghy
Russian Scientist
Acting
Richard Marner
Russian Air Force General
Acting
Allan Cuthbertson
Member of Whitehall Conference
Acting
Robin Bailey
Member of Whitehall Conference
Acting
Gerald Andersen
Member of Whitehall Conference
Acting
Gordon Phillott
Civil Sergeant
Acting
John Wood
Countryman
Acting
George Chisholm
Wine Waiter
Acting
Rosemary Scott
Launching Lady
Acting
Vincent Ball
Pilot
Acting
Frank Duncan
News Announcer
Acting
Ed Bishop
American Astronaut (as Edward Bishop)
Acting
Bill Edwards
American Astronaut
Acting
Laurence Herder
Russian Astronaut
Acting
Harvey Hall
Russian Astronaut
Acting
Frankie Howerd
Self
Acting
Beverly Bennett
(Uncredited)
Acting
Paul Beradi
Ukraine Delegate (Uncredited)
Acting
Ernest Blyth
Dignatory at Ship Launching (Uncredited)
Acting
Michael Caspi
(Uncredited)
Acting
Paul Cole
(Uncredited)
Acting
Douglas Cooper
Fenwickian (Uncredited)
Acting
Larry Cross
(Uncredited)
Acting
Victor Croxford
Valet (Uncredited)
Acting
George Curtis
Councillor (Uncredited)
Acting
Stringer Davis
1st Councillor (Uncredited)
Acting
Charles Dyer
Bit Part (Uncredited)
Writing
Lucy Griffiths
Lady-in-Waiting (Uncredited)
Acting
Sandra Hampton
April (Uncredited)
Acting
Robert Haynes
(Uncredited)
Acting
Murray Kash
(Uncredited)
Acting
Frederick Kelsey
Fenwickian (Uncredited)
Acting
Bruce Lacey
Bandleader (Uncredited)
Acting
Anthony Lang
Councillor (Uncredited)
Acting
Frank Lieberman
American Civilian (Uncredited)
Acting
Martin Lyder
Fenwickian (Uncredited)
Acting
Jack Mandeville
Representative at United Nations (Uncredited)
Acting
Coral Morphew
Peasant Girl (Uncredited)
Acting
Carolyn Pertwee
June (Uncredited)
Acting
Stuart Saunders
Sergeant (Uncredited)
Acting
Kevin Scott
American Journalist (Uncredited)
Acting
George Spence
Man in Market (Uncredited)
Acting
Reg Thomason
Opposition MP (Uncredited)
Acting
Fred Wood
Bird Seller (Uncredited)
Acting