Richie Porte (BMC) smashed into the back of a camera motorbike as crowds on Mont Ventoux, causing chaos in the final kilometres

Richie Porte (BMC) suffered a huge crash into the back of a motorbike as he powered up Mont Ventoux on stage 12 of the Tour de France.

Porte led a three-man breakaway from the group of main contenders, which also contained race leader Chris Froome (Team Sky) and Trek-Segafredo’s Bauke Mollema.

As the crowds swarmed the side of the road, the camera motorbike in front of the three riders came to a halt, forcing Porte to crash head first into the back of it.

>>> Chris Froome runs up Mont Ventoux after late crash (video)

Up the road, Thomas De Gendt (Lotto-Soudal) had already taken the stage, with the favourites racing five minutes behind to open up time gaps.

Froome was forced to run up part of the mountain as he waited for a new bike, while rivals like Nairo Quintana (Movistar) and Adam Yates (Orica-BikeExchange) moved ahead of him.

Yates provisionally moves into the yellow jersey, but the result may be changed after the incident.