Jon Pertwee

Character: The Doctor

Katy Manning

Character: Jo Grant

Nicholas Courtney

Character: Brigadier Lethbridge-Stewart

Richard Franklin

Character: Captain Mike Yates

John Levene

Character: Sergeant Benton

Roger Delgado

Character: The Master

Pik-Sen Lim

Character: Captain Chin Lee

Raymond Westwell

Character: Prison Governor

Michael Sheard

Character: Dr. Roland Summers

Simon Lack

Character: Professor Kettering

Fernanda Marlowe

Character: Corporal Bell

Neil McCarthy

Character: George Patrick Barnham

Clive Scott

Character: Arthur Linwood

Roy Purcell

Character: Chief Prison Officer Powers

Eric Mason

Character: Senior Prison Officer Green

Bill Matthews

Character: Prison Officer

Barry Wade

Character: Prison Officer

Dave Carter

Character: Prison Officer

Martin Gordon

Character: Prison Officer

William Marlowe

Character: Mailer

Hayden Jones

Character: Vosper

Kristopher Kum

Character: Fu Peng

Tommy Duggan

Character: Senator Alcott

David Calderisi

Character: Charlie

Patrick Godfrey

Character: Major Cosworth

Johnny Barrs

Character: Fuller

Matthew Walters

Character: Main Gates Prisoner

Timothy Combe

Character: Prisoner (uncredited)