Last updated 24 March 2024


Part Four

Series Episode Number: 417

World Premiere: Sat 13 Dec 1975 - 5:56pm GMT [BBC One] (United Kingdom)
First Broadcast: Wed 16 Apr 1980 - 5:30pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 30 seconds

11.40 Million (UK)


Chart Position: 15 () (UK)

Recorded on Sat 26 Jul 1975 in TC8



The Doctor and Sarah are desperate to warn UNIT of the alien invasion, but nobody will believe them. The Kraals' release their android duplicates, including one of the Doctor.


Production Team hide uncredited
WriterTerry Nation
DirectorBarry Letts
ProducerPhilip Hinchcliffe
DesignerPhilip Lindley
Script EditorRobert Holmes
Film CameramanKen Newson
Film SoundDoug Mawson
Film EditorMike Stoffer
Studio LightingDuncan Brown
Studio SoundAlan Machin
Visual Effects DesignerLen Hutton
Costume DesignerBarbara Lane
Make-upSylvia Thornton
Incidental MusicDudley Simpson
Special SoundDick Mills
Title MusicRon Grainer
and BBC Radiophonic Workshop
Title SequenceBernard Lodge
Production Unit ManagerJanet Radenkovic
Production AssistantMarion McDougall
Fight ArrangerTerry Walsh
Assistant Floor ManagerFelicity Trew (uncredited)
Floor AssistantSteven Fuller (uncredited)
Vision MixerNick Lake (uncredited)
Inlay OperatorMitch Mitchell (uncredited)
Grams OperatorGordon Phillipson (uncredited)
Studio Lighting AssistantAlan Arbuthnott (uncredited)
Film Camera AssistantPaul Godfrey (uncredited)
Film Sound AssistantHoward Gartska (uncredited)
GripRay Monks (uncredited)
Film OperativeLeslie Colliers (uncredited)
Film OperativeDick Norwood (uncredited)
Film Operations ManagerIan Brindle (uncredited)
Director's AssistantJoy Sinclair (uncredited)
Make-Up AssistantSandra Burcham (uncredited)
Make-Up AssistantJocelyn Cox (uncredited)
Visual Effects AssistantColin Mapson (uncredited)
Visual Effects AssistantLaurie Warburton (uncredited)
DresserMoira Fitzgerald (uncredited)
DresserGeorge Sherriffs (uncredited)
Title Music ArrangerDelia Derbyshire (uncredited)