Lake Windermere - why swimmer health could be at risk in World Heritage waters

It's England's largest natural lake and a world heritage site, with bathing waters classed as 'excellent’ by the Environment Agency.

But campaigners say Windermere's water testing regime isn't up to the job. They warn that, at times, the health of people swimming in the lake could be at risk.

Our North of England Correspondent Clare Fallon reports.