Britain’s Chris Froome was forced to run without a bike following a crash with a motorbike on one of the most iconic climbs of the Tour de France.

Froome crashed with Richie Porte and Bauke Mollema just over one kilometre from the finish on Mont Ventoux.

The defending champion was overtaken by rivals Adam Yates and Nairo Quintana in the melee but race organisers ruled Froome should retain the overall lead.

Thomas de Gendt won stage 12, which had been shortened because of high winds.

Speaking to French TV, Froome, the 2013 and 2015 champion said: “I was with Richie Porte and Bauke Mollema and all three of us went into the back of the motorbike. I got hit from behind by another motorbike that broke my bicycle.

“I told myself, ‘I don’t have a bike and my car is five minutes behind with another bike – it’s too far away, I’m going to run a bit’.”

The Team Sky rider finished one minute and 40 seconds behind Trek-Segafredo’s Mollema, who had immediately managed to remount his bike, and 44 seconds behind BMC’s Porte. But Porte and Froome were given the same time as Mollema, five minutes five seconds behind Lotto Soudal rider De Gendt.

Froome said: “I’m happy with the jury’s decision. I think it’s right. Thanks to them and thanks to the Tour de France organisation.”

Rocky, Bolt and running the bulls – Froome inspires online hilarity As Froome climbed towards the finish line at Chalet Reynard, Porte rode into the back of a motorbike, which seemed to stop suddenly because of crowds encroaching on to the road. Froome and Bauke Mollema crashed into the Australian and all three fell off their bikes. With his bike damaged, Froome set off on foot as he waited for a replacement.

According to the UCI, cycling’s governing body, a cyclist can cross the line on foot but only if they have their bike with them. He attempted to use a neutral service bike before switching to a third bike from the Team Sky car about 200 metres later, eventually crossing the line shaking his head.

Froome, who held a 28-second advantage over Yates overnight, extended his lead to 47 seconds, with Quintana – regarded as Froome’s biggest rival before the race – a further seven seconds adrift.

Porte, 31, said: “The crowd were all over the road and it was such a mess. It was just crazy.