Peter Davison as The Doctor

Matthew Waterhouse as Adric

Janet Fielding as Tegan

Sarah Sutton as Nyssa

James Warwick as Scott

Clare Clifford as Kyle

Beryl Reid as Briggs

June Bland as Berger

Steve Morley as Walters

Suzi Arden as Snyder

Ann Holloway as Mitchell

Anne Clements as Trooper

Mark Straker as Trooper

Alec Sabin as Ringway

Mark Fletcher as Crewmember

Christopher Whittingham as Crewmember

David Banks as Cyber Leader

Mark Hardy as Cyber Lieutenant

William Hartnell as The Doctor (1) (archive footage)

Patrick Troughton as The Doctor (2) (archive footage)

Tom Baker as The Doctor (4) (archive footage)