Britain's Ancient Tracks with Tony Robinson

Tony hikes across Dartmoor in the footsteps of Britain's greatest detective, plunges into a reputedly bottomless lake and comes face-to-face with a four-legged beast.

Tony walks Offa's Dyke in the footsteps of William Wordsworth, encounters Wales's fearsome dragon and ponders the priceless gold coin issued by King Offa in praise of Allah.

Tony uncovers a prehistoric shark tooth, shines a light in an abandoned railway tunnel and discovers DH Lawrence's mountain retreat in the Peak District.

Tony follows the Roman road of Dere Street north through Hadrian's Wall, contemplates the ancient night sky, braves the roar of a Celtic horn, mixes medieval potions and encounters ancient invaders.