Last updated 24 March 2024


Episode Four

Series Episode Number: 315

World Premiere: Sat 18 Mar 1972 - 5:50pm GMT [BBC One] (United Kingdom)
First Broadcast: Thu 20 Nov 1975 - 6:30pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 21 seconds

7.80 Million (UK)


Chart Position: 40 () (UK)

Recorded on Tue 30 Nov 1971 in TC8
Archive State: PAL 2 VT



The Doctor attempts to persuade Captain Hart of the danger that the Master represents. Eager to make contact with the Sea Devils, the Doctor journeys deep into the ocean.

Characters hide uncredited
Doctor WhoJon Pertwee
MasterRoger Delgado
Jo GrantKaty Manning
Captain HartEdwin Richfield
TrenchardClive Morton
Commander RidgewayDonald Sumpter
Lt. Commander MitchellDavid Griffin
3rd Officer Jane BlytheJune Murphy
Ldg. Telegraphist BowmanAlec Wallis
C.P.O. SummersColin Bell
Lt. Commander WattsBrian Vaughan
Castle Guard DrewStanley McGeagh
Sea DevilPat Gorman
Stunt ManTerry Walsh (uncredited)
Stunt ManStuart Fell (uncredited)
Stunt ManMarc Boyle (confirmed)
Stunt ManMike Horsburgh (uncredited)
Stunt ManPeter Brace (uncredited)
Stunt ManMike Stephens (uncredited)
Chateau GuardJim Dowdall (uncredited)
Chateau GuardBrian Gilmar (uncredited)
Sea DevilSteve Ismay (uncredited)
Submarine RatingNick Llewellyn (uncredited)
Sea DevilBryan Nolan (uncredited)
Submarine RatingRoy Pearce (uncredited)
Submarine RatingDennis Plenty (uncredited)
Submarine RatingRon Tingley (uncredited)
Chateau GuardPhillip Weston (uncredited)
Sea DevilGeoffrey Witherick (uncredited)
Production Teamhide uncredited
WriterMalcolm Hulke
DirectorMichael E Briant
ProducerBarry Letts
DesignerTony Snoaden
Script EditorTerrance Dicks
Visual Effects DesignerPeter Day
Film CameramanPeter Sargent
Film EditorMartyn Day
Special SoundBrian Hodgson
Incidental MusicMalcolm Clarke
Incidental Music BBC Radiophonic Workshop
Title MusicRon Grainer
Title Music BBC Radiophonic Workshop
With thanks to Royal Navy
CostumesMaggie Fletcher (uncredited)
MakeupSylvia James (uncredited)
Studio LightingMike Jefferies (uncredited)
Studio SoundTony Millier (uncredited)
Grams OperatorGordon Phillipson (uncredited)
Film Operations AssistantPW Walsh (uncredited)
Film Sound AssistantAlec Christison (uncredited)
Film Camera AssistantJohn Jefford (uncredited)
Makeup (Assistant)Joanne Burn (uncredited)
Technical Manager (TM2)Peter Valentine (uncredited)
Film Unit ElectricianJohn Collins (uncredited)
Film Camera AssistantIan Punter (uncredited)
Costume AssistantGrace Dawson (uncredited)
Artist BookingSybil Cave (uncredited)
Property BuyerJohn Watson (uncredited)
Production SecretarySarah Newman (uncredited)
Floor AssistantTony Cox (uncredited)
Costume AssistantJack Roe (uncredited)
Artist BookingPhyllis Page (uncredited)
Vision MixerJohn Gorman (uncredited)
Production AssistantPauline Silcock (uncredited)
Film Unit ElectricianTony Thorpe (uncredited)
GripBill Paget (uncredited)
Film Camera AssistantRoger Twyman (uncredited)
ArmourerDouglas Needham (uncredited)
Costume AssistantBarry Simmons (uncredited)
Fight Arranger HAVOC (uncredited)
Fight ArrangerDerek Ware (uncredited)
Director's AssistantPauline Silcock (uncredited)
Property BuyerJoe Bates (uncredited)
Assistant Floor ManagerJohn Bradburn (uncredited)
Production AssistantColin Dudley (uncredited)
Title Music ArrangerDelia Derbyshire (uncredited)
Title SequenceBernard Lodge (uncredited)
Location AssistantJennie Betts (uncredited)
DriverS Hedges (uncredited)
DriverEdward Kirkham (uncredited)
Location Transport Pergo Minibuses (uncredited)
Pergo DriverBert West (uncredited)
Location Catering Cinefood (uncredited)
Location Trailers Seacliff Holiday Caravans (uncredited)
Visual Effects AssistantLen Hutton (uncredited)