Tom Baker
The Doctor
Acting
Elisabeth Sladen
Sarah Jane Smith
Acting
Tony Beckley
Harrison Chase
Acting
Kenneth Gilbert
Richard Dunbar
Acting
Michael Barrington
Sir Colin Thackeray
Acting
Sylvia Coleridge
Amelia Ducat
Acting
John Challis
Scorby
Acting
Mark Jones
Arnold Keeler / Krynoid (voice)
Acting
Seymour Green
Hargreaves
Acting
Michael McStay
Derek Moberley
Acting
Hubert Rees
John Stevensen
Acting
John Gleeson
Charles Winlett
Acting
Ian Fairbairn
Doctor Chester
Acting
John Acheson
Major Beresford
Acting
Ray Barron
Sergeant Henderson
Acting
Alan Chuntz
Chauffeur
Acting
David Masterman
Guard Leader
Acting
Harry Fielder
Guard
Acting
Pat Gorman
Guard
Acting
Ian Elliott
Guard
Acting
Keith Ashley
Sir Colin's Aide
Acting
Ronald Gough
Marine
Acting
Patrick Milner
Marine
Acting
Barry Summerford
UNIT Soldier
Acting
Tony Snell
UNIT Soldier
Acting
Patrick Ginter
UNIT Soldier
Acting
Rowland Geall
UNIT Soldier
Acting
Derek Wayland
UNIT Soldier
Acting
Keith Ashley
The Krynoid
Acting
Ronald Gough
The Krynoid
Acting