Mark Cavendish underlined his status as the man to beat at next year's Olympic Games by winning the road race test event through London's streets on Sunday, but one competitor labelled the course "dangerous."

The tight and technical route caused several bottlenecks for the competitors and support vehicles as the 139-man field set a blistering pace to leave British spectators, unfamiliar with watching live road cycling, open-mouthed in astonishment.

Briton Cavendish, the Tour de France's most successful sprinter, won the 140.3-km event starting and finishing near Buckingham Palace in a time of three hours, 18 minutes, 11 seconds.

He paid tribute to the vast crowds, who turned up despite widespread rioting in London earlier in the week.

"It was incredible, it shows how many people are into road cycling in Great Britain at the moment," the 26-year-old told reporters.

"The course was so full you couldn't even take a wee," he joked earlier on the podium, his model girlfriend watching on.

Sacha Modolo of Italy was second and France's Samuel Dumoulin was third, the latter happy with his performance but not overjoyed about the narrow streets.

"At the end it's fine but at the start the route is not made for a race of this size," Dumoulin told reporters.

"It's pretty dangerous."

Cavendish was not bothered about the route's shortcomings and was typically unmoved despite attacks from Japanese riders towards the closing stages.

"It takes a brave person to try and push me off my leadout man. If I stay solid, they'll bounce off me, and that's what they did," the stocky Briton said.

Having withstood the attacks, there was only one outcome.

Cavendish stuck with the peloton, at one stage six minutes behind an early breakaway led by 2009 British road race champion Kristian House, before staging a customary late charge in a bunch sprint down the Mall.

Australian Heinrich Haussler, a former German Tour de France stage winner, led the peloton back to the breakaway riders as the race re-entered the UK capital's people-lined streets after sections in the leafy western suburbs.

Not in the mix at the end was American sprinter Tyler Farrar, who lost time after two gruelling circuits of the Box Hill summit. He said that is where the Olympic race could be won or lost next year given the riders will have to complete nine laps.

"I think the circuit is harder than people are giving it credit for," Farrar told a handful of reporters.

"Nine laps of that circuit will be quite hard, especially for guys like me. It will be unpredictable."

Team Sky boss Dave Brailsford agreed, saying Cavendish will have a real task on his hands to land the gold medal.

"He'll have to be in the shape of his life," Brailsford told reporters.

Manxman Cavendish, whose name has been linked to Britain's Team Sky after his successful HTC-Highroad announced they will fold at the end of the season, was kitted out in a blue outfit with the name of British cycling sponsors Sky emblazoned on it.

"Anybody would like Mark Cavendish on their team," a grinning Brailsford replied when asked if talks to sign the prolific winner were underway.

Watch video highlights from the 2012 Olympic Games cycling competitions right here on Roadcycling.com.