Red Bull's Mark Webber has disclosed that he raced the last four Grands Prix of the Formula One season with a broken shoulder and without telling his team he fell off a mountain bike in his native Australia in October.

The 34-year-old, who still has a pin in his leg after breaking the limb and shoulder in a cycling accident in Tasmania in November 2008, revealed the latest incident in a book Up Front - 2010, A Season to Remember published in Australia.

"I was riding with a great friend of mine. Suddenly he crashed right in front of me and I had nowhere to go but straight through the ears of the horse (over the handlebars)," Webber explained in the book.

"I suffered what they call a 'skier's fracture' to my right shoulder."

Webber was leading the championship at the time but his form then dipped and he ended up third overall with the title going to 23-year-old German team mate Sebastian Vettel.

Red Bull team boss Christian Horner, who accepted an award on his absent driver's behalf in London on Monday, was disappointed.

"I didn't even know about the book let alone the shoulder," the Daily Telegraph website quoted him as saying at the British Racing Drivers' Club (BRDC) function.

"It is obviously disappointing Mark said nothing. It was an injury that did not appear to have any effect on his performance, but all the same it would have been nice to know about it.

"Our drivers have an obligation to make sure they are fit. It seems bikes don't agree with Mark so maybe it would be better if he stayed away from them."

Singapore race

Webber's partner Ann Neal told Reuters the driver had returned home after the Singapore Grand Prix and gone out on a mountain bike for the first time since the Tasmania crash.

She said Webber, now in Australia, had not told the team about the fracture with only his physio Roger Cleary and FIA doctor Gary Hartstein in the know.

"He just got on with it," she said, playing down the severity of the injury. "He knew he could race the car, he just needed a few painkillers. There was never any fear he wouldn't be able to compete.

"It was painful for him at the time because he crashed on his shoulder."

Despite the injury Webber finished second in a Red Bull one-two in Japan.

He then crashed out in South Korea on a slippery wet surface and was again second behind Vettel in Brazil after accusing the team of favouring his teammate emotionally before a race in which Red Bull won the constructors' title.

While Vettel won the season-ending race in Abu Dhabi, the Australian trailed in eighth.