Matt Baker and Joe Crowley get their walking boots on as they visit Snowdonia National Park. Home to Wales’s largest natural lake and its highest mountain, Mount Snowdon, the park shot to the top of the staycation list last summer as more Brits than ever holidayed on home turf. But Snowdonia is paying the price for its popularity, as the heavy influx of tourists is taking its toll on the landscape. Matt finds out about the invisible scourge of micro-plastics plaguing the scenic landscape, while Joe mucks in with a mountain makeover as he helps repair the footpaths.

Tom Heap investigates the growing problem of vandalism and anti-social behaviour in our National Parks, and Adam Henson visits a farm in Wiltshire where cow dung is being used to generate electricity.