Last updated 24 March 2024


Episode Four

Series Episode Number: 282

World Premiere: Sat 23 Jan 1971 - 5:16pm BST [BBC One] (United Kingdom)
First Broadcast: Mon 27 Oct 1975 - 6:30pm CST [WTTW 11 Chicago]
Running Time: 22 minutes 10 seconds

8.40 Million (UK)


Chart Position: 59 () (UK)

Recorded on Sat 24 Oct 1970 in Television Centre 6
Archive State: PAL Restor



The Doctor and UNIT race to prevent the Master from broadcasting the deadly activation signal and opening the channel for the Nestene's arrival on Earth.


Production Team hide uncredited
WriterRobert Holmes
DirectorBarry Letts (uncredited)
ProducerBarry Letts
DesignerIan Watson
Script EditorTerrance Dicks
Special SoundBrian Hodgson
Special Sound BBC Radiophonic Workshop
Studio LightingEric Monk
Studio SoundColin Dixon
CostumesKen Trew
Make-upJan Harrison
Visual Effects DesignerMichaeljohn Harris
Fight Arranger HAVOC
Film CameramanJohn Baker
Film EditorGeoffrey Botterill
Incidental MusicDudley Simpson
Title MusicRon Grainer
and BBC Radiophonic Workshop
Production AssistantNicholas John (uncredited)
Technical ManagerGraham Southcott (uncredited)
Vision MixerShirley Coward (uncredited)
Grams OperatorLinton Howell-Hughes (uncredited)
Effects AssistantPeter Pegrum (uncredited)
Inlay OperatorJohn McPherson (uncredited)
Props BuyerMaurice Watson (uncredited)
Assistant Floor ManagerBruce Best (uncredited)
Floor AssistantEdward Pugh (uncredited)
AssistantRita Dunn (uncredited)
Pre-Production SecretaryPenny Forster (uncredited)
Facilities BookerJennie Betts (uncredited)
Artist BookingSybil Cave (uncredited)
Production SecretarySarah Newman (uncredited)
Title Music ArrangerDelia Derbyshire (uncredited)
Title SequenceBernard Lodge (uncredited)