Plunge into the chilly embrace of the UK's lakes and you enter troubled waters. They're a place for recreation and an inspiration for our greatest poets but they're also on the frontline in the battle against pollution. The biggest lake in the British Isles, Lough Neagh, is plagued with toxic green algae that sucks the life out of its waters, but nobody seems able to stop the relentless flow of agricultural, industrial and domestic pollution that feed it. Meanwhile, Lake Windermere, birthplace of the Romantic movement, is suffering from a record number of illegal sewage spills that make wildwater swimming a dicey business.

Tom Heap and Helen Czerski paddle through the history and legends of our lakes and lochs, search for solutions to their present day problems and celebrate the natural life that still flocks to these beautiful places.

Producer: Emma Campbell

Assistant Producers: Rebecca Rooney and Toby Field

Rare Earth is produced in association with the Open University