Mark Cavendish is taking time out before gearing up for his Olympic challenge next month.

Cavendish and Bradley Wiggins are world champions in the Madison event and among Britain's brightest medal hopes for Beijing. But the star sprinter from the Isle of Man was beginning to show signs of fatigue after his brilliant efforts in the Tour and decided to pull out of the event before yesterday's 15th stage headed higher into the Alps.

Cavendish, the first British rider to win four Tour stages in the same year, had the full backing of Team Columbia manager Bob Stapleton.

"He was very fatigued only halfway through Saturday's stage," said Stapleton. "It was very difficult for him to get over the Alps. Why take any more physical risks and put a workload on his body?"

Cavendish was joined on the drop-out list yesterday by Spaniard Oscar Pereiro, the 2006 Tour winner, who broke his left arm when he hit a crash barrier on the descent of the Col d'Agnel and fell five metres lower down. He was in 15th place at the time.

Britain's other Tour rider, David Millar, is 51st after being involved in a huge pile-up which also brought down American Christian Vande Valde.

The 15th stage was won by Australian Simon Gerrans. "I'm still pinching myself and I will for some time to come," he said. "It's such a fantastic thing in my career to win a stage in the Tour de France. It's amazing."

But his compatriot, Cadel Evans, lost possession of the yellow jersey. That will be worn tomorrow by Luxembourg's Frank Schleck, who holds a seven-seconds advantage over Bernhard Kohl, of Austria, with Evans one second further behind.