He is the fastest man in the world yet Jamaica's Usain Bolt is not the 100m world champion. His chances of taking the title were scuppered when he fell foul of the false start rule in the final.

The 25-year-old Olympic gold medallist, who still took home two gold medals from Daegu, was not the only one to have their world championships dreams dashed after jumping the gun.

Britons Dwain Chambers and Christine Ohuruogu both made shock exits after being disqualified in earlier rounds and Irish record holder Joanne Cuddihy's frustrations were clear when she was given the red card in the women's 400m semi-final.

Under the rule, athletes get just the one chance and anyone who makes a false start is automatically disqualified.

But despite the furore created at this year's IAAF World Athletics Championships, the athletics' governing body has confirmed it will not change the false-start rule before the 2012 Olympics in London.

London 2012 chief Lord Coe, an IAAF vice-president, said: 'The issue is very simple for me. You have to be consistent. You have a rule and you don't suddenly revisit it because a high-profile athlete has fallen foul.

'I'd rather not have Usain false start in London. But the start's not separate from the race; it is part of the race. It's not a technical nicety. It's part of the sport like a knockout punch in boxing.

'You pay to watch a title fight in Vegas knowing that a fighter might get knocked down in the first round.'

The rule was amended in 2010 to automatically disqualify anyone moving before the gun. Until 2001, every athlete had the right to one false start before risking disqualification but that led on occasion to several aborted starts before a race took place and was changed partly because of demands from television broadcasters.

Under the second version of the rule, athletes had the right to make one false start and then the whole field was given a warning with any subsequent false starts leading to disqualification.

But that brought the risk of what IAAF director of communications Nick Davies called 'a bit of gamesmanship', with athletes looking to remove any advantage fast starters have by deliberately false starting to put the field under pressure, hence a further change for 2010.

Elsewhere, swimming also has the same rule that any competitor who false starts is automatically disqualified.

Britain's Christian Malcolm said: 'There was nothing wrong with the rule they had before where it was one false start and then anyone would be disqualified after that.'