Major Jeff Cummings
Marshall Thompson
Prof. R. E. Walgate
Kynaston Reeves
Melville
Launce Maraschal
Ben Adams
Meadows White
Atomic Engineer
E. Kerrigan Prescott
Amelia Adams
Lala Lloyd
Nurse
Shane Cordell
Sentry (uncredited)
Sheldon Allan
Minister (uncredited)
Alexander Archdale
Jacques Griselle (uncredited)
Eddie Boyce
Villager (uncredited)
Victor Hagan
Victor Harrington
Barbara Griselle
Kim Parker
Sergeant in Office (uncredited)
Jack Hetherington
Townsman (uncredited)
Richard Neller
Technical Sergeant (uncredited)
Tom Watson
Col. Butler
Stanley Maxted
Capt. Al Chester
Terry Kilburn
Mayor Hawkins
James Dyrenforth
Const. Howard Gibbons
Robert MacKenzie
Dr. Bradley
Peter Madden
Dr. Warren
Gil Winfield
Sgt. Kasper
Michael Balfour
Assistant Director
Douglas Hickox
Director
Arthur Crabtree
Screenplay
Herbert J. Leder
Story
Amelia Reynolds Long
Producer
John Croydon
Executive Producer
Richard Gordon
Co-Producer
Ronald Kinnoch
Charles F. Vetter
Original Music Composer
Buxton Orr
Director of Photography
Lionel Banes
Editor
Richard Q. McNaughton
Hairstylist
Barbara Barnard
Makeup Artist
Jim Hydes
Production Manager
Set Designer
John Elphick
Sound Editor
Terry Poulton
Special Effects
Peter Neilson
Flo Nordhoff
Karl-Ludwig Ruppel
Continuity
Hazel Swift
Costume Supervisor
Anna Duse
Camera Operator
Leo Rogers
Conductor
Frederic Lewis
Sound Recordist
Peter T. Davies
Second Unit Director of Photography
Martin Curtis