Before I embark on my first-ever swimming trip, the greatest distance I’ve covered is a lunch-hour’s worth of lengths at my local pool. It’s probably much like yours — the air rich with chlorine, the water an eternally bracing temperature, nothing to look at but a bored lifeguard and a large clock. Like many I redoubled my wild swimming efforts during the lockdowns, but these were fleeting dips. So you’ll understand why I found the prospect of swimming several kilometres a day…