The Thames: Britain's Great River With Tony Robinson

Episode 4 (1x4)

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The actor visits the East End of London, going on patrol with the Metropolitan Police Marine Unit and attending an emergency call-out to an unexploded bomb. At Billingsgate fish market, Tony reflects on his teenage years working on the docks, before ending his journey in the Thames Estuary. He discovers that the river is now cleaner than it has been for 500 years, which is encouraging seals to once again claim the waters as their home.