Race leader Geraint Thomas and sprint king Mark Cavendish were brought down in separate crashes as Frenchman Arnaud Demare won a dramatic finish to the Tour de France fourth stage on Tuesday.

Briton Thomas, who had warned on Monday that he just wanted to stay clear of trouble on the 207.5km ride from Mondorf-les-Bains to Vittel, hit the deck for the second time in three stages.

His crash came on a bend just inside the final kilometre but Cavendish’s fall looked more spectacular, just a couple of hundred metres from the finish line.

Cavendish was baulked by world champion Peter Sagan against the metal barriers on the side of the road and crashed hard, with two riders, including German John Degenkolb, hitting the stricken Briton as they crashed over the top of him.

Cavendish had already crashed out of the Tour in the first stage in 2014 after breaking his collarbone in a sprint finish fall he later admitted was his fault.

While Thomas was able to get up and ride on to the finish, Cavendish needed medical assistance as he lay on the ground in obvious pain.

In all the furore of another bunch pile-up, Demare’s achievement of becoming the first Frenchman to win a Tour stage in a sprint finish since 2011 was almost lost.

His win allowed him to claim the sprinters’ green jersey from German Marcel Kittel, winner of Sunday’s second stage.

Sagan took second place with Norway’s Alexander Kristoff third on the stage.

Sagan’s time bonus on the line helped him move up to second overall at seven seconds behind Thomas, with reigning champion Chris Froome third at 12sec.