He was 14 and it was the very week he'd been selected to be the youngest ever competitor for the Pipeline Masters, which, in surfing, is as big as it gets. With the confidence soaring through his blood, and fermenting into cockiness, Johnson set out with his friend, the now seven-times world-champion Kelly Slater.

Jack, Kelly and a bunch of other North Shore surf dudes would practise every day, egging each other on to ride riskier and riskier waves. "Kelly dared me to make this wave and I made the drop, and I rode it and pulled up into the tube and travelled a little while in that," Johnson says in terms that will only make sense if you know a thing or two about making the drop and suchlike. "Then," he continues, "I tried to do something I'd done a million times before - drop off and jump through the back of the wave."

Mmmm, I nod, as if this was just the kind of thing I got up to on a daily basis as a kid.

"As I tried to jump through the back, the whole wave closed out. It sucked the water away and opened up the reef underneath, which I landed on face first and blacked out. By the time I came back to the surface the next wave was breaking over the top of me, so I must have been out for about 12 seconds. I was awake, but aware that I was drifting off, and I kept thinking, 'OK, you've just hit your head real hard and you've gotta start swimming.' I don't know if I was in shock or a little paralysed but I couldn't move. It was like an alarm clock going off, when you keep pushing the snooze button and you know you've got to get to work and all of a sudden the clock goes off again and you look at it and realise you're late for work. I kept pushing that snooze button and thinking, 'Give me a few more seconds.'

"And then I was under, and I swallowed water, which jarred me awake. At that point, I realised, 'OK, I'm gonna drown here.' So I swam to the surface and threw up on the beach in front of my house. Luckily, there was a paramedic staying next door."