The War Machines

From http://www.bbc.co.uk/doctorwho/classic/episodeguide:

The TARDIS arrives in London in 1966 and the Doctor and Dodo visit the Post Office Tower. There they meet Professor Brett, whose revolutionary new computer WOTAN (Will Operating Thought ANalogue) can actually think for itself and is shortly to be linked up to other major computers around the world - a project overseen by civil servant Sir Charles Summer.

It transpires however that WOTAN considers that humans are inferior to machines and should therefore be ruled by them. Exerting a hypnotic influence, it arranges the construction of War Machines - heavily-armed, self-contained mobile computers - with which to take over the world.

These prove more than a match for troops, but by establishing a magnetic force field the Doctor is able to capture one of them, which he then reprograms to destroy WOTAN. Dodo, now back in her own time, decides to remain on Earth. The Doctor enters the TARDIS alone, but Brett's secretary Polly and her merchant seaman friend Ben Jackson follow him inside just before it dematerialises.

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