‘Water has always had the magical power to cure.’ With this guiding conviction tucked into his Speedos, writer and environmentalist Roger Deakin set out to swim the length and breadth of Britain. Two decades after Deakin completed this feat, wild swimming has turned from a fringe pursuit into a ‘thing’. For a non-swimmer like myself, this presents a profound mystery. If you must take to the water, what’s wrong with the leisure-centre pool? Rivers, lakes, canals, fens, estuaries: these are places where Weil’s disease lurks and hypothermia awaits. They’re beautiful, for sure, from the vantage point of the shore or a boat, but not in swimming togs, in winter, in the rain.