Guest Stars Lynda Bellingham as The Inquisitor Michael Jayston as The Valeyard Malcolm Tierney as Doland Honor Blackman as Professor Lasky Yolande Palfrey as Janet Arthur Hewlett as Kimber Leon Davis as Ortezo Michael Craig as Commodore Travers Denys Hawthorne as Rudge Sam Howard as Azta David Allister as Bruchner Barbara Ward as Ruth Baxter Simon Slater as Edwardes Bob Appleby as Second Vervoid Peppi Borza as First Vervoid Hugh Beverton as Guard Uncredited Richard Bonehill as Hyperion III Officer
