"An American tourist, a youth gang leader, and his troubled sister find themselves trapped in a top secret government facility experimenting on children."
Macdonald Carey
as Simon Wells
Shirley Anne Field
as Joan
Viveca Lindfors
as Freya Neilson
Alexander Knox
as Bernard
Oliver Reed
as King
Walter Gotell
as Major Holland
James Villiers
as Captain Gregory
Tom Kempinski
as Ted
Kenneth Cope
as Sid
Brian Oulton
as Mr. Dingle
Barbara Everest
as Miss Lamont
Allan McClelland
as Mr. Stuart
James Maxwell
as Mr. Talbot
Rachel Clay
as Victoria
Caroline Sheldon
as Elizabeth
Rebecca Dignam
as Anne
Siobhan Taylor
as Mary
Nicholas Clay
as Richard (as Nicolas Clay)
Kit Williams
as Henry
Christopher Witty
as William
David Palmer
as George
John Thompson
as Charles
Fiona Duncan
as Control Room Guard (uncredited)
León García
as Teddy Boy (uncredited)
Victor Gorf
as (uncredited)
Michael Carreras
Executive Producer
James Bernard
Original Music Composer
Evan Jones
Screenplay
Arthur Grant
Director of Photography
Bernard Robinson
Production Design
Joseph Losey
Director
Reginald Mills
Editor
Anthony Hinds
Producer
H.L. Lawrence
Novel
Don Mingaye
Art Direction
Molly Arbuthnot
Costume Design
Malcolm Cooke
Sound Editor
Roy Ashton
Makeup Artist
Don Weeks
Production Manager
John Hollingsworth
Music Supervisor
John Peverall
Assistant Director
Anthony Heller
Camera Operator
Jock May
Sound Recordist
Pamela Davies
Continuity
Frieda Steiger
Hairstylist
Wardrobe Supervisor
Stuart Lyons
Casting
Anthony Nelson Keys
Associate Producer