The actor and comedian explores the waterways of the west of Great Britain. He follows the Severn from its source in the Welsh hills to its estuary 200 miles away, and also travels along its neighbour the Wye. Griff examines how rivers have nurtured and provided for mankind for thousands of years, supplying drinking water as well as the iron ore used in the Industrial Revolution, and also bog snorkels, meets Druids and sleeps in a hermit's cave

• Griff Rhys Jones