Jon Pertwee as The Doctor

Katy Manning as Jo Grant

Nicholas Courtney as Brigadier Lethbridge-Stewart

Richard Franklin as Captain Mike Yates

John Levene as Sergeant Benton

Roger Delgado as The Master

Pik-Sen Lim as Captain Chin Lee

Raymond Westwell as Prison Governor

Michael Sheard as Dr. Roland Summers

Simon Lack as Professor Kettering

Fernanda Marlowe as Corporal Bell

Neil McCarthy as George Patrick Barnham

Clive Scott as Arthur Linwood

Roy Purcell as Chief Prison Officer Powers

Eric Mason as Senior Prison Officer Green

Bill Matthews as Prison Officer

Barry Wade as Prison Officer

Dave Carter as Prison Officer

Martin Gordon as Prison Officer

William Marlowe as Mailer

Hayden Jones as Vosper

Kristopher Kum as Fu Peng

Tommy Duggan as Senator Alcott

David Calderisi as Charlie

Patrick Godfrey as Major Cosworth

Johnny Barrs as Fuller

Matthew Walters as Main Gates Prisoner

Timothy Combe as Prisoner (uncredited)