Guest Stars Douglas Wilmer as Prof. Van Dusen Margaret John as Receptionist Veronica Strong as Miss Rossmore / Mrs. Morey William Moore as Station Sergeant Mark Eden as Roderick Varley Charles Morgan as Mallory Robert Hartley as Police Doctor Wallas Eaton as Sterling Dennis Chinnery as Morey Michael Guest as Policeman Laurence Payne as Prescott William Mervyn as Sir Hector Drummond, Bt.