James Donald

Michael Heathley

Phyllis Calvert

Lydia Heathley

Noel Willman

Dr. Dennis Bord

Herbert Lom

Dr. Alex Leon

Robert Beatty

Maj. Sam Seagram

Patric Doonan

Brian Jackson

Walter Fitzgerald

Sir Charles Craddock

Muriel Pavlow

Caroline Cartier

Maurice Denham

Prof. Carrington

Marjorie Fielding

Michael's Mother

Herbert Lomas

George Jackson

Geoffrey Denton

Fisher

Cyril Chamberlain

Inspector Carter

Hal Osmond

Agent Lawson

Caven Watson

Dr. Ferguson

Marianne Stone

Maisie

Stanley Maxted

Prof. Adams

Hartley Power

General Adams (uncredited)

Philip Ray

Sentry (uncredited)

Johnnie Schofield

Jim Barnes (uncredited)

John Warren

Ted (uncredited)