Hugh O'Brian as Hugh Lombard

Shirley Eaton as Ann Clyde

Fabian as Mike Raven

Leo Genn as General Mandrake

Stanley Holloway as Det. William Henry Blore

Wilfrid Hyde-White as Judge Arthur Cannon

Daliah Lavi as Ilona Bergen

Dennis Price as Dr. Edward Armstrong

Marianne Hoppe as Elsa Grohmann

Mario Adorf as Joseph Grohmann

Bill Mitchell as Narrator (voice)

Christopher Lee as Mr. U.N. Owen (voice)