Colin Baker Doctor Who Actor Nicola Bryant Peri Brown Actor Lynda Bellingham The Inquisitor Actor Michael Jayston The Valeyard Actor Tony Selby Sabalom Glitz Actor Brian Blessed King Yrcanos Actor Malcolm Tierney Doland Actor David Allister Bruchner Actor Glen Murphy Dibber Actor Tom Chadbon Merdeen Actor Michael Craig Commodore Travers Actor Denys Hawthorne Rudge Actor Roger Brierley Drathro Actor Arthur Hewlett Kimber Actor Tony Scoggo Grenville , Enzu Actor Billy McColl Humker Actor Leon Davis Ortezo Actor Bob Appleby Second Vervoid Actor Peppi Borza First Vervoid Actor Hugh Beverton Guard , First Guard Actor Pip Baker Writer Robert Holmes Writer Philip Martin Writer Jane Baker Writer Nicholas Mallett Director Ron Jones Director John Nathan-Turner Producer Chris Clough Director Eric Saward Script Editor