It means the 25-year-old Welshwoman becomes the first cyclist, male or female, to win world and Olympic road race titles in the same year.

In a thrilling finish to the 138.8 kiometres race, held over eight laps of an undulating circuit in the Italian town close to the Swiss border, Cooke demonstrated why she is one of the greatest women cyclists of modern times.

Stuck in a five-strong group with two Germans and two former world champions, Cooke followed all the right moves in a chaotic final lap that saw attacks from Holland's Marianne Vos, Emma Johansson and Trixi Worrack of Germany all fail.

Johansson, who finished second behind Cooke in the Olympic road race, had attacked just before the red flag signalling the final kilometre but the Swede floundered inside the final few hundred metres.

As the finish line approached German's Judith Arndt pulled ahead briefly, but when Vos went off on her own it was the talented Dutchwoman's wheel that Cooke decided to jump on.

Vos, a 21-year-old multi-discipline champion in the sport who won the points race gold at the Beijing velodrome, appeared to stop her effort only metres from the finish line.

But whether that was a misjudgement or a sudden loss of energy, Cooke kept hammering the pedals and crossed the finish line in triumph.

Cooke completed the 86-mile race in 3 hours, 42min 11sec, the same time as Vos and more than a minute ahead of the main pack.

She said: "I tried to get back on her wheel.

"After a long race 100 metres can seem more like 200.

"When I started the race I was very relaxed because I'd already achieved my goal for the year which was to win the Olympics."

It caps a hugely successful year for Cooke, who won World Championships bronze in 2006, silver in 2005 and bronze in 2003.

It was Cooke's victory on the second day of competition in Beijing that started Britain's gold-rush of a record 19 Olympic gold medals and it will probably always be the highlight of her career.

But this latest triumph will run it close.

Cooke said: "I have always wanted the winner's rainbow jersey.

"At the finale I tried my best, it was instinct.

"It was a really hard race."

Vos said: "Last year I started my sprint too late and this year I thought I had gotten it just right.

"When I looked back and saw Nicole coming on strong I knew I couldn't win.

"I'm still second, it's still a spot on the podium."