
The biggest thing since creation!
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.
Jack MacGowran
Dr. Sampson, the paleontologist

Maurice Kaufmann
Mini Submarine Officer

Henri Vidon
Tom Trevethan

Patrick Jordan
Photo Lab Aide
Howard Lang
Naval Commader, at the "Valkyrie" wreck (uncredited)

Leonard Sachs
Dialogue Scientist at Conference (bit)
Ernest Blyth
Scientist at Conference (uncredited)
Neal Arden
TV Newscaster (uncredited)
Paul Beradi
Man Listening to Car Radio (uncredited)

Max Faulkner
PLA Radio Operator (uncredited)