Last updated 24 March 2024


Episode Six

Series Episode Number: 288

World Premiere: Sat 6 Mar 1971 - 5:15pm BST [BBC One] (United Kingdom)
First Broadcast: Fri 14 Nov 1975 - 6:30pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 48 seconds

7.30 Million (UK)


Chart Position: 65 () (UK)

Recorded on Sat 19 Dec 1970 in Television Centre 3
Archive State: 16mm t/r



The Keller Machine breaks free of the Doctor's restraining device and the Doctor has no choice but to turn the parasite against the Master.


Production Team hide uncredited
WriterDon Houghton
DirectorTimothy Combe
ProducerBarry Letts
DesignerRaymond London
Script EditorTerrance Dicks
Special SoundBrian Hodgson
and BBC Radiophonic Workshop
Studio LightingEric Monk
Studio SoundChick Anthony
CostumesBobi Bartlett
Make-upJan Harrison
Videotape EditorSam Upton
Videotape EditorRoger Harvey
Film CameramanMax Samett
Film EditorHoward Billingham
Visual Effects DesignerJim Ward
Incidental MusicDudley Simpson
Title MusicRon Grainer
and BBC Radiophonic Workshop
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)
Director's AssistantJohn Elliott (uncredited)