Last updated 24 March 2024


Episode One

Series Episode Number: 283

World Premiere: Sat 30 Jan 1971 - 5:15pm BST [BBC One] (United Kingdom)
First Broadcast: Fri 7 Nov 1975 - 6:30pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 39 seconds

6.10 Million (UK)


Chart Position: 61 () (UK)

Recorded on Sat 21 Nov 1970 in Television Centre 3
Archive State: 16mm t/r



At Stangmoor Prison, the Doctor and Jo watch a demonstration of the Keller Machine which can extract evil impulses from criminals. But the experiment goes wrong and a man dies.


Production Team hide uncredited
WriterDon Houghton
DirectorTimothy Combe
ProducerBarry Letts
DesignerRaymond London
Script EditorTerrance Dicks
Special SoundBrian Hodgson
Special Sound BBC Radiophonic Workshop
Studio LightingEric Monk
Studio SoundChick Anthony
CostumesBobi Bartlett
Make-upJan Harrison
Visual Effects DesignerJim Ward
Incidental MusicDudley Simpson
Title MusicRon Grainer
and BBC Radiophonic Workshop
Film CameramanFred Hamilton (uncredited)
Film CameramanMax Samett (uncredited)
Film EditorHoward Billingham (uncredited)
Production AssistantJohn Griffiths (uncredited)
Assistant Floor ManagerSue Hedden (uncredited)
Technical ManagerGraham Southcote (uncredited)
Vision MixerMike Catherwood (uncredited)
Floor AssistantJohn O'Shaughnessy (uncredited)
Title Music ArrangerDelia Derbyshire (uncredited)
Title SequenceBernard Lodge (uncredited)
Videotape EditorSam Upton (uncredited)
Videotape EditorRoger Harvey (uncredited)
Director's AssistantJohn Elliott (uncredited)