Walter Summers Director, Screenwriter Bruce Cabot Carl Beyersdorf , Ted Healey Actor Marta Labarr Freyda Healey Actor Tamara Desni Marie Dufreyne Actor Romilly Lunge Beverley Blake Actor Edward Lexy Det. Insp. William Barnard Actor Cyril Smith Det. Sgt. Trotter Actor Percy Walsh Otto Lemnel Actor Alexander Field Yorkie Meane Actor Hilary Pritchard Toni Vencini Actor Davina Craig Mabel Actor Vincent Holman Hawker Actor Anthony Shaw Commander Anderson Actor Peter Gawthorne Sir John Actor Eve Lynd Florrie McGowan Actor John Argyle Screenwriter, Producer Jan Van Lusil Screenwriter Ralph Gilbert Bettison Screenwriter Robert LaPresle Cinematographer Ted Richards Film Editing Ian White Production Design