John Saxon as Dr. Jack Costain

Patricia Haines as Ann Barlow

Alfred Burke as Detective Supt. Hartley

Maurice Denham as Dr. Morley

John Carson as The Major

Ballard Berkeley as Cmdr. Savage

Stanley Meadows as Det. Tom Grant

Barbara French as Joyce Malone

Robert Crewdson as Medra

Aubrey Morris as Thorburn

Jack Watson as The Sergeant

Tony Wager as Pvt. Higgins

David Gregory as Pvt. Jones

Marianne Stone as Madge Lilburn

Warren Mitchell as Reg Lilburn

Geoffrey Lumsden as Col. Davy

Douglas Livingstone as 2nd R / T soldier

Tom Gill as Police Commissioner's secretary

Vincent Harding as First R/T Soldier

Romo Garrara as Lieutenant

John Sherlock as TV Newscaster