We have all seen it at the local pool. A young lad, full of bravado, climbs up to the high diving board, waves at his mates, then looks down. Suddenly he is not so brave. What next? Conquer his fear and jump, or climb down to his sniggering mates?
There is consolation for anyone who has been in that position; the world champion understands your fear, he has been there.
Tom Daley is the boy who captured the hearts of grandmothers, teenage girls, and many others when he competed in the 2008 Bejing Olympics at the grand old age of 14. A year later he became the 10-metre platform dive world champion in Rome, following that with two Commonwealth golds in Delhi. Still too young to vote, he is one of Britain's brightest hopes for next summer's Olympics.
But every day, every dive, Daley is frightened as he stands on that platform, suspended in mid-air. As he is currently diving more than a dozen times a day in preparation for the FINA World Championships, which begin this weekend in Shanghai, that is a lot of fear to be conquered.
"I get scared every time I go up there," he says when we meet. "That adrenaline doesn't go away. It gets easier as you go through a training session, but you're still scared when you go up there. Anyone would be. I wouldn't believe a diver who said they're not."
Ten metres is higher than the average home. It is equivalent to stacking two London buses on top of each other, adding a family car, then jumping off the roof. Daley's speed when he hits the water from that height is 34mph. "It is constant impact – you don't see many old divers. It still hurts even if you land correctly."
Daley knows, even with his talent there are no guarantees of that. A bruised temple and scarred forehead are proof of that. Even since becoming world champion Daley has, in horse racing parlance, refused. In late 2009, he recalls: "I landed flat on a dive. There were bruises everywhere. Every time I went up there again, I had a blank. I thought: 'I just can't do it'." Daley contemplated moving to the 3m springboard, only resuming his usual programme and event after a month's work with his coach Andy Banks.
That was an improvement on the eight months it took when he first lost confidence after landing flat at the age of 12. "I'd never had that feeling before of getting lost in the air, not knowing where I was, not knowing how I was going to land, and then landing flat. It's a horrible feeling not knowing which way is up."
Such dis-orientation would hardly be a surprise. Daley's dives are, to the uninitiated, impossibly complicated. When he steps, leaps or jumps off the platform his body whirls and twirls, twists and tucks, before straightening out to slip into the water with barely a ripple. And when he competes in the synchronised diving with partner Peter Waterfield the pair must mirror each other with perfect symmetry. Thus the constant and relentless practice.
The rehearsals stop on Sunday when Daley and Waterfield compete in the 10m platform synchro in Shanghai. The following weekend Daley defends his individual 10m platform title.
It will be an emotional time for Daley, for this is the 17-year-old's biggest event since his father, Rob, died of brain cancer at the age of 40. Daley is talking to promote Nestle's "Get Set Go Free" campaign, which is why he has been photographed climbing an orange wall he has no intention of diving off. An understandable condition is that he is not asked about his father, who was buried last month, but he is inevitably in Daley's thoughts. There is a poignant moment when he discusses the possibility that, should he win gold at London 2012, he might get drunk for the first time in his life. "I'll probably go out with my mum and dad and get wasted that night. I'll be 18 then." After a brief pause he corrects himself: "I'll go out with mum, brothers, everyone will be out."
As with all British athletes, the home Olympics loom large. While eager to retain his world title Daley is using Shanghai as a testing ground for his 2012 programme, showcasing four new dives (of the six in a routine) for the first time at this level of competition. This reduces his chances of retaining his world title, but 2012 is the undoubted focus.
Diving is very popular in China and the home support will be behind 18-year-old Qiu Bo, who has replaced Daley as world No 1. While Daley averages 35 dives a week, stepping up to 50 or more near competition, Qiu Bo does around 150. "The Chinese are doing way more training than me. They do three hours of school a week whereas I'm doing A levels. They train ridiculous amounts. If I did their training regime I would get injured but because they have so many divers on tap they don't mind if they get to the stage where they break."
Daley is one of a handful of foreign divers who gets recognised in the streets in China. "They call me 'Baby Daley' because they remember me from Bejing, but I'm like, two feet taller than them. I've grown a lot since they last saw me!"
He smiles, but it may be a problem in his sport. Platform divers tend to be short, it makes it easier to get the tucks and turns completed before hitting the water. Daley has grown seven inches since Bejing and at 5ft 9in now towers over his 5ft 6in partner. "I'll probably be the tallest platform diver [competing]. It does make it quite tough with the harder dives. I am still growing in little bits but I don't think I'll get to six feet. As long as I train through it I shouldn't have a problem."
Daley has been in training since he was eight. Like most prodigies his childhood seems restrictive to the outsider but he is happy with it. "I have lots of friends there so it is a social thing as well as a diving thing. I still get to be a kid, like on weekends. I just have to be sensible. You don't need to be going out all the time. You can go to parties, drink water, and still have fun." There is, he adds, fun to be had in being the only one with total recall of a big night.
Teenagers tend to be demonised in the modern media but Daley is a credit to his parents and not just for his athletic prowess. Articulate and engaging, he seems unaffected by his fame, an attribute which will serve him well as the months tick down to next summer when Britain will suddenly become absorbed by the intricacies of 10m platform diving.
Tom Daley is fronting Nestlé's Get Set Go Free campaign which gives families the opportunity to try out 27 activities, including martial arts, swimming, dancing, and scuba diving, for free over the summer holidays and beyond. Visit www.getsetgofree.com for more details.