Tony Robinson embarks on a 200-mile journey from source to sea to discover what makes the Thames one of the greatest rivers in the world.
He begins by tracking down the source of the waterway, as it emerges from the ground as a pure spring in a Gloucestershire field. He then follows the river as it winds its way through the Thames valley, stopping off at Henley-on-Thames, and then on towards the palace at Hampton Court.
Reaching central London, Tony boards an industrial working ship on the Thames, learning it is a route not without risks as ships must squeeze under bridges at high tide and avoid running aground at low tide, before getting a bird’s-eye view of the river from the Shard. Tony then visits the East End of London, reflecting on his teenage years working on the docks, and ends his journey in the Thames Estuary.