Contador was in second place overall and half a minute off the lead when Andy Schleck's chain came off. The friendly etiquette in such races means that riders do not attack the race leader if they fall or suffer a mechanical problem.

Shleck quickly got his chain back on, but finished the stage eight seconds behind Contador overall. Schleck was very angry and said that he wanted to get revenge, until Contador apologised.

"The race was in full gear and, well, maybe I made a mistake," said Contador. "I'm sorry."

Contador won the race in 2007 and 2009, and is now in a good position to win his third title. Our picture shows Schleck leading Contador down the Col du Tourmalet on today's stage.