I wonder if he’s still alive today: the boy I nearly didn’t save from drowning.

I was thirteen, at the lido with Julie. She could swim a mile, but I could only doggy paddle. I was frightened of deep water, especially when I saw the black lines wiggling on the bottom. ‘Sixfoot’ was one of the scariest words I knew. And ten was unimaginable, deeper even than the ceiling in my bedroom. But fear comes close to fascination, and Julie would entertain me by letting herself down to the floor and slowly rising up again. And then she’d streak off on her own, leaving me to mess around at the shallow end.

The boy was a pest. He must have been about eleven, shorter than me, but a stocky little chap. He would leap knees hunched and land with an almighty splash beside me; and, after being almost sunk a few times, I realised he wasn’t doing it accidentally. When Julie came back, she told him to scram.

“Go take a running jump in your own pond!”

We decided to play at walking along the edge, to see how far we could get before it got too deep. We were holding our chins high as we reached the five foot, so then we climbed out and dangled our legs over the side, chatting about schoolgirl things.

“Look, there’s that boy again!”

The little show-off came full pelt and bounded into the water straight in front of us, although the momentum took him quite far out. His cheeky face popped up before me, and then submerged again. He was going up and down like Julie did, only the water was barely over his head. I watched, fascinated, until his eyes met mine and I thought I glimpsed an expression of despair.

And then, to my shame, I did nothing.

It’s called bystander apathy. It happens all the time. People look around to check what everyone else is doing. And the other swimmers were clearly unconcerned. The lifeguards weren't diving off their high chairs. Julie had a bronze award, and she hadn’t budged. So I was going to let a kid drown because I didn’t want to make a fool of myself.

It took the explicit command of a passer-by to make me act.

“That boy’s drowning! Do something!”

I didn’t wait for Julie. I waded chin-deep through the water, lifted him under the oxters and carried him to safety, whilst my lifesaver friend looked on open-mouthed.

With all his bravado, we’d assumed he could swim.