John Gregson (Commander Malcolm Stevenson), Jayne Sofiano (Mollie Gordon), Frederick Hall (Professor Ormsby), Jerome Willis (Major Norman), Bernard Archard (Jenkinson), Paul Grist (Billy Gordon), Michael Barrington (Colonel Feddon), Robert Harris (Sir David Carter), Rex Robinson (Marston), Walter Horsbrugh (Dr Mackenzie), Susan Whitman (Edna), Karen Ford (Adela), Damaris Hayman (Waitress), and Harry Davies (Police Sergeant).