Britain's Mark Cavendish has been forced to pull out of the Tour de France after breaking his shoulder in a crash.

World champion Peter Sagan has been disqualified for sending Cavendish crashing into the barriers just 120 metres from the finish line.

Video footage from the race shows Sagan cycling towards Cavendish before edging in front of him and nudging him with his elbow.

A gasp of shock can then be heard coming from one commentator as Cavendish is seen hitting the barrier and then crashing onto the road and into the path of other oncoming racers.

The crash, which happened as contestants sprinted into Vittel on stage four, left Cavendish and his bike sprawled on the road with other cyclists swerving to try and avoid hitting him.

Immediately afterwards, Cavendish told reporters that he got on well with Sagan, but he didn't understand why he elbowed him.

"If he came across that's one thing, but the elbow, I'm not a fan of him putting his elbow in me like that."

Sagan, who has since apologised to Cavendish, said: "Mark was coming pretty fast from the back. I tried but didn't have time to react to go left. He came to me and I had to defend."

The Slovakian was initially docked 30 seconds for the crash but was disqualified after the race jury reviewed the footage and ruled he had "endangered some of his colleagues seriously in the final metres of the sprint".

It is a bitter blow for Cavendish who has just spent three months battling Epstein-Barr virus in order to make the start line of the Tour in Dusseldorf.

The 32-year-old said: "I'm obviously massively disappointed to get this news about the fracture.

"The team was incredible today.They executed to perfection what we wanted to do this morning.

"I feel I was in a good position to win, and to lose that and even having to leave the Tour - a race I have built my whole career around - is really sad."

His doctor Adrian Rotunno said fortunately Cavendish will not need surgery and there is no nerve damage.

"He's been withdrawn from the race for obvious medical reasons, and we'll continue monitoring him over the coming days, " he added.