A chaotic men's 100 metres final ended in farce at the London Grand Prix on Friday after officials switched from electronic to manual timing in the evening's showpiece event.

After a start delayed by some 15 minutes, European champion Dwain Chambers eventually won the race in an unrecorded time.

A false start by American champion Bernard Williams started the delays and then Chambers's British team mate Darren Campbell complained that music was coming out of his starting blocks.

Officials switched from electronic to manual timing which resulted in a time of 9.53 seconds -- 0.25 of a second inside the official world record -- being flashed on the board when Chambers edged Commonweath gold medallist Kim Collins.

Collins was credited with 9.56, also clearly erroneous.

"The problem is we switched from electronic to manual timing," an official said. "There's a possibility that the times won't be recorded."

Eventually times were produced which were even less enlightening. Each of the first five were credited with an even 10 seconds.

World record holder Tim Montgomery was already out of the competition after a dreadful start in his heat.

The 28-year-old American was left standing at the start, made up some ground in the middle of the race but then faded to sixth in a heat won by Collins in 9.97 seconds.

"I slipped in the blocks," said Montgomery, who also finished sixth in Tuesday's Stockholm grand prix. "It was my mistake. It is going to take some more races to get where I need to be. After a terrible start I was at least able to come up through the field and hold on."

Even without a proper time, Chambers was elated after an excellent race so close to the world championships, which take place in Paris starting August 23.

"This was a world championship final minus Maurice Greene," he said.

American women's 100 metres champion Kelli White equalled her best time of the year with a decisive victory over Ukrainian world gold medallist Zhanna Block.

WHITE WINS

White confirmed she would be the favourite at the Paris world championships along with veteran Chandra Strurrup of the Bahamas by clocking 10.93 seconds with a following wind of 1.3 metres a second on a hot, sultry night at Crystal Palace.

Former U.S.champion Chryste Gaines was second in 10.99 with Block struggling to hold third place.

"I know I am in pretty good form so I expected to be able to run fast," said White. "I have been feeling good all season. I will go to Paris feeling extra confident after tonight.

"I have taken a month off from competition to train and to iron out all the strains. I am now going to run Berlin on Sunday and hope to perform even better."

Kenya's Edith Masai recorded a significant victory over Olympic and world champion Gabriela Szabo in the women's 5,000 metres, outsprinting the Romanian in the final straight. Olympic and world 10,000 champion Derartu Tulu finished third.

World record holder Yelana Isinbayeva beat Russian team mate Svetlana Feofanova in the women's pole vault, with both women making unsuccessful attempts at a new record height of 4.83.

Cuban Yamile Aldama won the women's triple jump with an impressive final leap of 15.27 metres, only two centimetres short of her year's best. German Boris Henry relegated Britain's European champion Steve Backley to second place in the men's javelin with a throw of 85.77.

Olympic and world champion Jonathan Edwards was stretchered form the arena after injuring his right ankle in the men's triple jump. Medical officials said he was expected to be fit for Paris.