1971-01-30 • 25 min
The Doctor and Jo head to Stangmoor Prison to investigate the Keller Machine, which drains the evil impulses from prisoners' minds, while UNIT are handling security at the first world peace conference.
Roger Delgado
The Master
Richard Franklin
Mike Yates
John Levene
Sergeant Benton
Pik-Sen Lim
Captain Chin Lee
Raymond Westwell
Prison Governor
Michael Sheard
Dr. Summers
Simon Lack
Professor Kettering
Fernanda Marlowe
Corporal Bell
Clive Scott
Linwood
Roy Purcell
Chief Prison Officer Powers
Bill Matthews
Prison Officer
Barry Wade
Prison Officer
Dave Carter
Prison Officer
Martin Gordon
Prison Officer
Neil McCarthy
Barnham
Eric Mason
Senior Prison Officer Green
Nicholas Courtney
Brigadier Lethbridge-Stewart
Don Houghton
Writer
Stuart Humphryes
Color Designer
Dudley Simpson
Original Music Composer
Jan Harrison Shell
Makeup Artist
Jim Ward
Visual Effects
Barry Letts
Producer
Timothy Combe
Director
Bobi Bartlett
Costume Design
Howard Billingham
Editor
Ray London
Production Design