Lightning Bolt strikes gold:

Usain Bolt sensationally defended his coveted title as the fastest man on the planet tonight as he sprinted to glory in an Olympic record time of 9.64 seconds.

In front of a global TV audience estimated at up to two billion, the 25 year-old Jamaican answered all the questions about his fitness and state of mind to retain his 100-metre sprint crown in what had been billed ‘the greatest’ race of London 2012 – and certainly the most anticipated.

Known around the world as ‘Lightning Bolt’, he lived up to the legend to run the second-fastest time ever and beat his fellow Jamaican Yohan Blake, who claimed silver with a time of 9.75, and American Justin Gatlin, who won bronze in 9.79.

Left trailing were American Tyson Gay and Bolt's fellow Jamaican Asafa Powell.

Champion again: Jamaica's Usain Bolt crosses the finish line to win gold in the men's 100-metre final in the Olympic Stadium in London

Outright winner: Usain Bolt streaks clear of the field to claim gold from lane seven in one of the most eagerly awaited Olympic events ever

Showman: Usain Bolt celebrates his victory by striking his customary lightning bolt pose in the Olympic Stadium in London

The race had been billed as the ‘hottest ticket’ of London 2012 with people paying prices of up to £725 to be among those in the stadium who could forever say 'I was there'.

In Britain alone the TV audience was expected to be about 15million – a quarter of all Britons – with theatres and cinemas putting on special screenings that had begun in time to the semi-finals earlier in the evening.

Despite earlier heavy rain and soggy conditions, thousands who had been at other venues inside the Olympic park on so-called ‘Super Sunday’ and ‘Showdown Sunday’ stayed to watch the race on the big screens.

Among those watching last night was American Harrison Dillard, 89, the gold medallist from 1948, the last time the Olympics were held in London.

His time of 10.3 seconds wouldn’t have won him a place in the 2012 final.

Number one: Usain Bolt celebrates retaining his title in an Olympic record time of 9.63 seconds

Taking a bow: Jamaica's Usain Bolt kneels and rests his head against the track in the Olympic Stadium after recording the second-fastest time ever

Storming in front: Bolt (second left) crosses the finish line first, ahead of fellow Jamaican Yohan Blake (second right) and bronze medallist Justin Gatlin (centre)

Global appeal: Some 80,000 spectators in the Olympic Stadium watched the 100-metre race, as well as an estimated worldwide television audience of up to two billion

Rapid results: Bolt ran the second-fastest time ever - an Olympic record of 9.63 seconds. Yohan Blake won silver with a time of 9.75 and Justin Gatlin took bronze in 9.79. Seven men clocked a time below 10 seconds

Tonight's race had been hyped as a direct showdown between Jamaica's two top runners, with other athletes expected to trail in Bolt and Blake's wake. 

And the event took on greater significance for Jamaica because it fell on the 50th anniversary of the Caribbean island’s independence from Britain.

Ninety-two per cent of Jamaica’s population was expected to watch the race.

Bolt's win will cause bookmaker Ladbrokes to pay out more than half a million pounds to punters across the UK.

The gold medallist began his semi-final as the odds-on 5/6 favourite but after jogging through another heat the firm immediately cut his odds to 1/4.

And one Bolt fan who was so sure the Jamaican would do the business bet £60,000 on Bolt at 1/4.

They're off: Usain Bolt (third left) started well in lane seven and was comfortably leading the field as the athletes entered the final 20 metres

World order: American bronze medallist Justin Gatlin (left) can only look on with envy as Jamaica's Usain Bolt (right) rewrites Olympic history once again

Before the semi-finals the firm were quoting 2/1 that Bolt's world record would be broken, which got backed into 6/4 before the off. However it was odds-on at 8/15 the record would remain untouched.

Jessica Bridge of Ladbrokes said: 'Bolt played us all for a fool and the bookies fell for it hook, line and sinker. He's the most expensive Olympian of all time and we'll be glad to see the day when he gets beat.'

An extraordinary false start and disqualification in the 2011 World Championships, the loss of both national sprint titles, had raised questions over Bolt’s state of mind coming into the Olympics and moved the aura surrounding Bolt that had over his fellow sprinters.

It had been a difficult season for the triple Beijing sprint gold medallist who made a sluggish start in April, by his exceptionally high standards, of 10.04 seconds at a meet in the Czech Republic but then followed it with the second-fastest 100m of the year, 9.76 seconds, at the Rome Diamond League.

Hamstring trouble has restricted his public appearances this year, although famously he did appear with Prince Harry during a royal visit to Jamaica.

The mystery of the injury and a trip to a German doctor – Bolt claimed this week he was only 95 per cent fit - had led to a lot of support for Blake from former champions.

Psyched: Jamaica's Yohan Blake, pictured gesturing prior to competing in his semi-final, was one of the favourites for the Olympic title as he came into the race in excellent form

Fighting fit: Usain Bolt, who had been troubled by a hamstring injury, claimed he was only 95 per cent fit but he looked in fine condition before the eagerly awaited sprint final

Confident: Usain Bolt (right) looked assured in his semi-final, finishing comfortably ahead in a time of 9.87 seconds. Great Britain's Dwain Chambers (left) clocked a time of 10.05 seconds and failed to reach the final

Among those doubters was American Olympic legend Carl Lewis, the only sprinter to retain the 100m title and another was Sydney sprint champion Maurice Greene who warned : ‘Usain will go out there and continue to do the things he does... but Blake is going to win.’

 

Despite the doubts, Bolt remained his usual brash, confident self declaring last month: ‘I’ve been saying this for years: this will be the moment, this will be the year, this is my time.’

Gatlin, a former Olympic champion controversially competing in London after serving a four-year doping ban, had qualified for the final fastest, recording a time of 9.82 seconds in his semi-final.

Blake and Bolt won their semi-finals with impressive times of 9.85 and 9.87 respectively, although both men appeared to be holding back to conserve energy.

Seven of the eight finalists broke the 10-second barrier to qualify, with the slowest competitor, Richard Thompson of Trinidad and Tobago, making it through in 10.02 seconds.

American sprinters Tyson Gay (9.90) and Ryan Bailey (9.96), Jamaica's Asafa Powell (9.94) and the Netherlands' Churunday Martina (9.91) completed the line-up.

There were no British representatives in the final after home hopes Dwain Chambers and Adam Gemili narrowly missed out.

Chambers ran 10.05 seconds and Gemili ran 10.06 in their semi-finals, coming within hundredths of a second of places in the final.

Fervour: Spectators from the Jamaican community in Brixton, south London, watch their heroes in action on television on the 50th anniversary of the Caribbean island's independence from Britain

Quickest in the heats: Justin Gatlin (right), running for the U.S., qualified for the final fastest with a semi-final time of 9.82 seconds. His participation in London was controversial as he had served a four-year ban for doping

Gemili, a promising footballer who only turned to sprinting full-time in January, said he intended to remain in athletics.

'I am going to stick with athletics and see how it goes,' he told BBC Radio 5 live.

'Hopefully I can improve the times and become more consistent. The guys yesterday did so well.

'It boosts me up and makes me want to go forward and maybe one day be in the same position as them and win a gold medal for Great Britain at the Olympics.'

Chambers told the BBC: 'I wanted to do well and get into the final but I am happy to be here.

'I am gutted I didn't make the final, but I can't have it all.

'It was worth it all to feel that atmosphere. Money can't buy that.