We're very much into the meat of this climb up Grand Colombier - the wheat and the chaff will be separated.

BBC Radio 5 Live

You can hear the BBC Radio 5 live commentary team talk you through the final 90 minutes or so of this stage. 

Just click the audio button at the top of this page.

Rob Hatch
BBC Radio 5 live commentator

I think Mark Cavendish is the best sprinter in the world again now. 

I'd be the first to say - I did not think in my wildest dreams that he would come here, dominate the sprints and win four stages. 

I thought he'd be a competitive force, but I just thought it would be more even between him, Marcel Kittel and Andre Greipel.

So all of that has left us with seven riders out in front. They include Sebastien Reichenbach, who is 11mins 41secs behind Chris Froome in the GC.

The gap is currently 8mins 45secs - so the yellow jersey is not completely safe.

Daniel Navarro bridged from the chase group to the lead group and has just carried on past them.

But there's a response, mainly from Reichenbach and Zakarin.

Nibali looks like he's dropping off though.

The four men in the lead looks set to become three, with Pantano dropping off. They're looking up from the bottom of Grand Colombier now - here comes the hard bit. They're 10km from the top.

The group behind is starting to fall to pieces and some try to get back in touch with the leaders.

The peloton is 8mins 29secs behind.

Rob Hayles
Former GB cyclist

Kittel had no grounds for complaint, Cavendish just moved across slightly and Kittel was fighting his bike, he was well and truly beaten. 

I think he was showing more signs of frustration than anything else.

Image source, Getty Images

Mark Cavendish did two things yesterday.

He won his fourth stage of this year's Tour, but also made Marcel Kittel do an impression of a neighbour yelling at kids to get off his lawn.

The German felt he was obstructed by the Manx Missile - in truth he was just left in a trail of smoke from a flying Cav.

Tom Dumoulin has a few looks behind him. It seems he's decided that he doesn't fancy going the rest of the stage by himself, so is going to let a few riders catch up for support.

One of those is Vincenzo Nibali. Jarlinson Pantano and Alexis Vuillermoz also bridge the gap to make it a four-man lead group.

Image source, Getty Images

Thomas Voeckler is in the group of 28 riders behind Dumoulin and Nibali.

The Frenchman has previous on Grand Colombier, having won stage 10 of the 2012 Tour - the only other time the mountain has featured in the competition.

We saw plenty of that trademark tongue on that day.

Here's a preview of what's to come...

Vincenzo Nibali is going to lie down and let Tom Dumoulin disappear into the sunset. The Italian grinds o and pulls away from the breakaway to mount a chase.

Tom Dumoulin throws a dummy to Dylan van Baarle - looks like he's dropping off the pace and then switches on the afterburners.

It leaves Van Baarle looking silly but, more importantly, has got the rest of the breakaway panicking.

If Dumoulin gets out of sight, they will struggle to catch him.

They're on a climb by the way, but it's not categorised.

Dylan van Baarle has pulled out in front of the breakaway, with Tom Dumoulin giving chase.

You let Dumoulin get away on his own at you're peril.

That leaves 28 men in the group behind, which is 6mins 47secs ahead of the peloton.

Geraint Thomas said this would be one of the hardest stages on this year's Tour.

Hard is a word that seems to be theme for the day....

The peloton starts the descent, through lush, green-tree lined roads. this will enable Cavendish to get some speed and get back in the group.

We see Mark Cavendish trying his darndest to keep within touching distance of the peloton as they come up to the summit of Col de la Rochette.

The Manx Man needs to survive today's stage and the trip through the Alps, in order to be there for the sprint in Paris on the final day.

We'll take a look back at Cav's marvelous day yesterday.