On screen
Cast
16 credited performers
Patricia Neal
Susan North
Helmut Dantine
The Stranger
Derek Bond
Arthur Walker
Cyril Luckham
Dr. Meinard
Willoughby Gray
Tom Harding
Artwork unavailable
Marigold Russell
Gretchen Harding
Arthur Young
Scientist
Kenneth Edwards
Charles Dixon
Artwork unavailable
David Garth
First Police Officer
Stanley Van Beers
General
Nigel Green
Second Police Officer
Artwork unavailable
Graham Stuart
Police Chief
Jack Gwillim
Representative of Parliament (uncredited)
John Le Mesurier
Official/Man at Desk (uncredited)
Hugh Moxey
Secretary of the Interior (uncredited)
Peter Sallis
Soldier (uncredited)