The surface of Wastwater is so immaculately still that the thought of disturbing it with a swim seems like blasphemy. Earlier in the morning, social media reliably informed me that Wasdale was “overcrowded”. In the balmy grip of an August heatwave, Twitter gave the impression that the whole valley had been turned into a chaos of clogged roads, dirty campers and “wrong sorts” leaving devastation in their wake. But here on the shingly shore of Wastwater, on the edge of a wood, we have the place completely to ourselves. Where are the invading hordes? From here we can see right down the length of Wasdale: pyramidal Great Gable at the head of the valley, framed by the slopes of Yewbarrow and the Scafell massif. The view is a photographic cliche, but several days of stomping around the fells before this have rekindled my appreciation for Wasdale, with its formidable but familiar mountain forms, and right now it seems as beautiful as if I’d seen it for the first time. My girlfriend slips in first, sending perfect circles rippling out across the clear pane of the water. I wade into the pebbly, olive-green shallows and swim out into England’s deepest lake, with the water soon darkening beneath me. This is an oligotrophic lake, naturally nutrient-poor, but there are a few fish to be found here – including the rare Arctic char (Salvelinus alpinus) – and I hear soft gloops around me. A crane fly, a living legacy of the Cretaceous, skims over the surface of the water, seems to give me a quick inspection, and wobbles off. The craggy wall of the Wasdale Screes is big, brutal and sublime, but softened by rays of hazy morning sunshine streaking down between its gothic crags and buttresses. A peregrine flies through one of the sunbeams, pursued by a croaking raven. Some distance from the shore, I float on my back in the water, looking up at the sky and the Screes. When I come out of the trance, I look back in horror to see the masses have finally overrun our idyll: a young family playing on a paddleboard, seemingly having a great time of it. • The headline of this article was amended on 21 August 2020. An earlier version mistakenly referred to Wastwater as Britain’s deepest lake, rather than England’s deepest lake as the article itself said.