Glen Mills jokes that he's never sprinted in his life, except when trying to avoid getting run over by a car in Jamaica. So this laid back 58-year-old is in no hurry to make the fateful decision which could either protect or destroy the time-honoured status of the men's 100metre sprint as the blue riband event of the Olympic Games.

For Mills is the coach of Usain Bolt, simply the most thrilling athlete in the sport today. And while Games organisers, international athletics officials and the whole of Jamaica are desperate for the world 100m record holder to stamp his new iconic status on the short sprint, Mills will have the final say - and he still hasn't made his mind up.

"Usain will run the 200metres but he wants to do the 100 as well - but I've said to him 'You have to demonstrate to me that you are ready to do both'," Mills told Standard Sport after his charge flew in to Britain to compete in the Aviva London Grand Prix at Crystal Palace.

"Everybody in Jamaica's saying he must run the 100. I don't worry about it. I have to make my decision and not be influenced by outside. The only person who can influence me is Usain." The dilemma for Mills is this. Bolt, inevitably nicknamed 'Lightning' since his remarkable performances as a beanpole 15-year-old, had been concentrating all his preparations for Beijing on the 200m when the promise of his 'boy wonder' youth was fulfilled by his incredible flirtation with the 100m.

In New York in May, he sped to an astounding new world record of 9.72sec. Suddenly, everyone assumed that he would double up at 100m and 200m in Beijing but Mills is still worried that by running the marquee event against the world's other two fastest, Tyson Gay and Asafa Powell, the 21-year-old could compromise his half-lap chances.

The prospect of a three-way showdown in Beijing was further damaged last night by Gay's withdrawal from the 100m at Crystal Palace on Friday with an injury that may threaten his Olympic hopes, but Mills is concerned only about his charge - who will run just the 200m at Crystal Palace at the weekend.

"Say he runs the 100 and it doesn't go the way we planned and then it cost us the 200. We'd be empty handed wouldn't we?" said Mills. "The way it looks, the 200 is almost a shoe-in."

Yes, but surely it was unthinkable that the world record holder wouldn't compete for the sport's ultimate prize?

"I, too, would prefer to see him win the 100 but we have time; he's only 21," said Mills. "I'm not prepared to make a decision until after we've been to the training camp in Beijing."

Mills, whose laid back character mirrors that of his charge, reckoned that Bolt's 100m defeat by his compatriot Powell in Stockholm on Wednesday had raised new concerns - particularly over his start.

"If he gets starts like that in the quarters and semis in Beijing, he could be a spent force in the final," said Mills.

Still, had Bolt dipped at the line he could have tied the race after a blistering second 50m.

In a 200m in Athens 11 days ago, he clocked 19.67sec, the sixth fastest ever. Yet Mills reckoned he had run "a miserable race" and expects him to be quicker on Saturday. If so, it will be easily the fastest half-lap ever witnessed in Britain.

This is a must-see athlete. Donovan Bailey, the 1996 Olympic champ, recently hailed Bolt as the man with "the ability to recreate the sport and to be the biggest track and field athlete ever" and Mills laughs that if he could ever get him interested in the 400m - "Usain's not a lover of hard work," he smiles - he could even "get pretty close" to Michael Johnson's world record of 43.18sec.

More than that, Mills sees him as a role model for a sport tainted by drugs scandals. If eyebrows were raised at his world record, Bolt's coach merely shrugs: "I can understand the cynics viewing with suspicion outstanding performances but from where I sit, I can't even get Usain to take natural vitamins.

"It's not going to be easy, but he can bring back respectability and credibility to sprinting."

I still have a hunch he'll bring back a 100m gold, too.

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