Lydia Heathley
Prof. Michael Heathley
Maj. Sam Seagram
Dr. Alex Leon
Caroline Cartier
Dr. Dennis Bord
Sir Charles Craddock
Brian Jackson
Prof. Carrington (project director)
Mother Heathley
Dr. Ferguson (as Cavan Watson)
George Jackson
Agent Lawson
Fisher
Insp. Carter
Maisie
Myrna (scenes deleted)
Prof. Adams
Control room operator (uncredited)
Security policeman (uncredited)
Mabel (uncredited)
General Adams (uncredited)
Sentry (uncredited)
Jim Barnes (uncredited)
Ted (uncredited)