Born in September 1994, Didon sometimes splashed in the sea as a child but never went out of his depth. Now he enjoys hearty ocean swims and has inspired his sister to get in the water.

He puts his rapid success down to doing push-ups and also the daily shots of vitamins from the mangoes and papayas he plucks from trees in his garden when he comes back from training.

“I’m strong,” he says, grinning. “I’m 13 but I’m doing the same time as some of the ones who are 14 and 18.”

Didon, who trains around four hours a day back home, will be up against tough competition in the 50 metres freestyle on Thursday, where his fastest rivals beat his qualifying time by 7 seconds. Yet he already has his eye on the 2012 Olympics, by which time he will have doubled his time in the sport.

Missing home

He is also itching to get back to the piercing blue skies and sweet air of the Seychelles, which has a population of around 82,000 and has yet to take home an Olympic medal.

“It feels polluted here. I can feel it in my lungs,” he said, tapping his chest and nodding at the blanket of smog over Beijing. “I want to go back home.”