"Marine atomic tests cause changes in the ocean's ecosystem resulting in dangerous blobs of radiation and the resurrection of a dormant dinosaur which threatens London."
Gene Evans
as Steve Karnes
André Morell
as Prof. James Bickford
Leigh Madison
as Jean Trevethan
John Turner
as John
Alastair Hunter
as Dr. C. A. Morris, the village doctor
Lloyd Lamble
as Senior Admiral, at the Admiralty
Jack MacGowran
as Dr. Sampson, the paleontologist
Maurice Kaufmann
as Mini Submarine Officer
Henri Vidon
as Tom Trevethan
Patrick Jordan
as Photo Lab Aide
Howard Lang
as Naval Commader, at the "Valkyrie" wreck (uncredited)
Leonard Sachs
as Dialogue Scientist at Conference (bit)
Ernest Blyth
as Scientist at Conference (uncredited)
Neal Arden
as TV Newscaster (uncredited)
Paul Beradi
as Man Listening to Car Radio (uncredited)
Max Faulkner
as PLA Radio Operator (uncredited)
Neil Hallett
as Dr. Sampson's Helicopter Pilot (uncredited)
André Maranne
as French Radio Officer (uncredited)
Derren Nesbitt
as The Radar Operator, at the radar room (uncredited)
Guy Standeven
as Naval Officer in Situation Room (uncredited)
Douglas Hickox
Director
Eugène Lourié
Screenplay
Daniel James
Robert Abel
Story
Alan J. Adler
David Diamond
Producer
Ted Lloyd
Edwin Astley
Original Music Composer
Ken Hodges
Director of Photography
Lee Doig
Editor
Production Design
Harry White
Art Direction
Irving Block
Special Effects
Louis DeWitt
Willis H. O'Brien
Pete Peterson
Jack Rabin
Desmond Davis
Camera Operator
Richard Marden
Sound Editor
Bernadette Ibbetson
Hairstylist
Jimmy Evans
Makeup Artist
Kim Mills
First Assistant Director
Jacques de Lane Lea
Production Manager
Jennifer Herrinshaw
Continuity
Sid Wiles
Sound
Freda Gibson
Wardrobe Master
Conductor
Visual Effects