The Thames: Britain's Great River With Tony Robinson

Beginning at the river's source in Gloucestershire, Tony meets a professional crayfish catcher, investigates the water's cleanliness, and learns the uses to which the Home Guard put the river during World War II.

Tony follows the river through the Thames valley, stopping off at Henley-on-Thames, and towards Hampton Court, a distance of around 100 miles. It's a stretch of the river mostly commonly associated with boating, but 200 years ago, was a trade route.

Tony reaches central London. Around four million tonnes of freight are shipped on it each year, but onboard an industrial ship, Tony learns it is a route not without risks, as ships go under bridges at high tide and avoid running aground at low tide.

The Thames is busier than ever, twenty four hours a day, seven days a week. Tony starts his journey this week at night - with a visit to New Covent Garden Market, a fruit and veg trade market just a stone's throw from the Thames, where restaurants and hotels from all over the South East come to buy their fresh produce.

The Thames has a long history of inspiring people. In this episode, Tony travels as far as the Estuary in the East and Waterhay in the West, to reveal some remarkable and ambitious examples of this. He starts his journey heading up the Estuary to Southend Pier - as a young man he'd drive here with friends.

Tony explores the role the Thames plays now and has played in the past in providing clean water, taking away sewage and irrigating natural habitats along its banks.