The men's 100 metres is the jewel in the Olympic crown and Yohan Blake's surprise humanisation of Usain Bolt has ensured that next month's showdown will be a race worthy of the Games rather than a mere time trial for the defending champion.

World champion Blake beat Bolt over 100m and 200m in the Jamaican trials and though the double world record holder was carrying a minor injury, the upsets have added real spice to the London 2012 sprints.

With fellow Jamaican Asafa Powell and Americans Tyson Gay and Justin Gatlin also in hot form and injury free, the 100m final on August 5 is promising to live up to its billing as the hottest ticket in town.

There are plenty of others, though, for the sport at the heart of the Olympics.

As one of the few countries to send organised supporter tours to overseas athletics events, Britain has a long-standing love of the sport and the atmosphere in the Olympic Stadium is certain to be something to remember.

It is likely to peak when Mo Farah bids to become the first Briton to win a long distance gold when he goes in the 10,000 metres and possibly again in the 5,000.

Heptathlete Jessica Ennis and 400 metres hurdler Dai Greene represent Britain's other best hopes of gold in a programme again likely to be dominated by the United States, Russia, Jamaica and the East African nations.

The U.S. topped the athletics medal table in Beijing with seven golds among a haul of 23 but they were knocked off their traditional perch in the sprints by Jamaica.

STUPENDOUS QUALITY

The Caribbean island will send a squad of stupendous quality led again, despite his trials setback, by Bolt.

Having wowed the world with his showboating world record run in Beijing then lowered his mark to a stunning 9.58 seconds in Berlin two years later, all the talk since has been about how fast he could go in London.

But training partner Blake, who won the 2011 world title when Bolt was disqualified for a false start, showed that there is a race to be won first when he clocked a personal best and season-leading 9.75 to win the Jamaican trials then repeated the dose with victory in the 200m.

Bolt opted out of a planned race in Monaco later this month to have treatment on a tight hamstring so the next time he leaves the blocks competitively will be in his 100m heat on Aug. 4.

Nobody, least of all Blake, will be thinking Bolt Has had his day, but the champion will have to be fully recovered physically, and mentally secure of his fitness, to explode out of the blocks and avoid the shocking start he had in the trials.

That could open the door for his rivals.

"I'm the Olympic champion so I have to show the world I am still the best," said Bolt, who will team up with Blake to defend Jamaica's 4x100m relay title.

"I know what I need to do to get it right. I just have to get my stuff together."

Jamaica took a 1-2-2 in the women's 100m four years ago with Shelly-Ann Fraser-Pryce winning gold ahead of tied-second Sherone Simpson and Kerron Stewart.

PERSONAL BEST

Fraser-Pryce, who ran a personal best 10.70 to win the Jamaican trials, Stewart and Veronica Campbell-Brown will line up in the 100, with the latter also bidding for an unprecedented third successive 200m gold.

Standing in her way, and looking to make her own unique mark on the Games, is American Allyson Felix, who clocked the best 200m time in 14 years when she won the U.S. trials in 21.69.

Felix will go over 100m, 200m, 4x100 and 4x400 where she will hope to mine the gold that has proved so elusive at Olympic level despite coming freely in world championships.

Twice second to Campbell-Brown in Olympic 200m finals, her solitary gold came in the Beijing 4x100. By contrast she has eight world championship golds, including three in the individual 200.

The national rivalry is even more intense in the longer distances, where Kenya and Ethiopia are likely to dominate and will happily use team tactics to achieve individual glory.

In Beijing the two countries won every men's race above 400m, including the marathon, while East African women triumphed in the 800m, 1500, 5,000 and 10,000 and took silver in the steeplechase and marathon.

Somalia-born Farah is hoping to become the first European 10,000 metres champion since Italy's Alberto Cova in 1984.

His chief rival, world record holder Kenenisa Bekele, is seeking an unprecedented hat-trick over the distance having also won the 5,000 four years ago.

Farah won the world title at 5,000 last year having been edged out on the line in the 10,000 and both men could double up again in London, the 10,000 coming up first.

British expectation for Farah this time round pales alongside that which Liu Xiang faced in Beijing four years ago, and the disappointment when China's main athletics hope and 2004 Olympic champion pulled out of the 110 metres hurdles injured was felt throughout the country.

Cuba's Dayron Robles, who had broken Liu's world record, before the Games, took gold in his absence and their rivalry has continued to develop, not least after last year's world championship when Robles beat Liu but was disqualified after clashing arms with his rival.

The highlight of the field event programme could be the women's pole vault where, having won two of the three competitions since its introduction in 2000, Russian Yelena Isinbayeva is also seeking a memorable hat-trick.

- Reuters