And once I got into the lake, it was lovely. The entrance is a gently sloping sandy beach, so there’s no undignified scrambling in over pebbles and rocks trying not to fall over – you just walk down into the water until it’s up to your chest or wherever (waiting politely for the duckling fleet to pass) and then start to swim. The circuit is clockwise, round three white buoys if you’re doing 450 metres, or six or so red buoys if you’re doing 750. I had set myself to do at least two 750 circuits, which I knew should be well within my capability as I’ve swum quite a few miles in the last month or two, and a third if I felt up to it. That would be 2.25 K, my longest swim of the year so far.

My eyesight isn’t great, so I squinted a bit to see the first buoy, a bit hard to pick out in the distance from the red and orange caps of swimmers, and set off towards it. The water felt cold as it spread into my suit, and for the first hundred yards or so I felt a bit breathless, and wondered if I’d even be able to do my prescribed two circuits. But I calmed myself down, reminded myself that the first two or three hundred yards of any long swim are always horrible as the body warms up, and concentrated on getting into my stroke.

And you know what? It was lovely. Entirely gorgeous. The water at Shepperton is clear and fresh, fresh, fresh – it tastes like you could drink it. I never realised before that swimming pool water doesn’t taste fresh, but compared to Shepperton it tastes chemical and grubby. The sun was sending shafts of light through the greeny-brown water which were fanning out and creating an optical illusion so strong and disorienting I almost had to shut my eyes. On my right as I turned to breathe was the expanse of the lake in the sunshine, on the left, the bank with willows and flags and beyond them an open stretch which I knew was the banks of the Thames and the river itself. It was beautiful to look at and far less boring than the buildings at either side of The Oasis, or even the Lido’s coloured doors.

And there was so much space! Even in the Lido a long swim is tiring as you try to avoid crashing into other people on every length. You have to keep looking ahead and it disrupts your rhythm. In Shepperton we were all going the same way so there was no need to look apart from the occasional head up to sight the next buoy. There were other swimmers, but we mostly gave each other a wide berth (with the sole exception of one annoying chap who literally swam over me – I shouted after him “Oi, mate, big lake!” which doubtless told HIM!). Once I was in the water and swimming, all I had to do was swim.

More tomorrow.