'The Android Invasion' (4 Parts) Story Code '4J' by Terry Nation

The TARDIS arrives on Earth in the sleepy village of Devesham. The Doctor and Sarah notice that the locals are behaving very oddly, acting like robots and answering to strange signals, and they are attacked by hostile mechanics with guns for fingers. The Doctor realises that he and Sarah are actually on the planet Oseidon, where the alien Kraals have created an exact replica of the village and its nearby Space Defence station. Styggron, the alien Chief Scientist, has created android version of the population, as part of a rehearsal for a planned invasion attempt, and has duped a lost human astronaut, Guy Crayford, into collaborating with him. While the TARDIS travels onto Earth alone, the Doctor and Sarah follow in the pods that the Kraals are using to send the androids to the planet surface. Meanwhile, Crayford, together with Styggron, returns to Earth in his spaceship, and is hailed as a hero. The Doctor and Sarah attempt to convince the UNIT troops at the Space Defence station of the danger from the impending invasion, but with the Brigadier away in Geneva, their warnings are ignored. The Doctor uses the transmitters at the station to jam the control signals of the androids, which include duplicates of himself, Harry Sullivan and RSM Benton. Styggron kills Crayford, but the Doctor reprogrammes his android double, and sends it to stop the alien from releasing a virus that will weaken human resistance. During the ensuing fight, Styggron is infected by the virus and is killed, halting the invasion.

Tom Baker (Doctor Who), Elisabeth Sladen (Sarah Jane Smith), Milton Johns (Guy Crayford), Peter Welch (Morgan), Max Faulkner (Corporal Adams), Martin Friend (Styggron), Dave Carter (Grierson), Ian Marter (Harry Sullivan), Roy Skelton (Chedaki), John Levene (RSM Benton), Stuart Fell (Kraal), Patrick Newell (Colonel Faraday), Hugh Lund (Matthews), Heather Emmanuel (Tessa)

Produced by Philip Hinchcliffe
Directed by Barry Letts

TX:
Part 1 - 22nd November, 1975 @ 5.45pm - 6.10pm
Part 2 - 29th November, 1975 @ 5.45pm - 6.10pm
Part 3 - 6th December, 1975 @ 5.45pm - 6.10pm
Part 4 - 13th December, 1975 @ 5.55pm - 6.20pm

Notes:
*Featuring the Fourth Doctor, Sarah, Harry and UNIT

*Working titles: 'The Enemy Within' and 'The Kraals'