Jakob Fuglsang, a team-mate of Astana race leader Vincenzo Nibali slams into the asphalt on the descent and the peloton slows at the request of Nibbles.

Danish rider Fuglsang is soon back up and riding but the slowing of the peloton means De Marchi's lead is approaching four minutes.

John McEnerney:, external VN will be on his guard his team will be watching AV like hawks, mightn't be 2day but will be soon when we see AV attack the YJ.

Tim Bell:, external Here we go, his first real test. If Nibbles can cover the GC attacks in this heat, it's as good as over.

The riders are descending to Grenoble.

According to a colleague who is a little more cultured than I, 19th Century French romantic writer Stendhal, real name Henri Beyle (Stendhal was his pseudonym) said of Grenoble: 'Au bout de chaque rue, une montagne' - 'At the end of every street, a mountain'.

Despite being surrounded by mountains, it's the flattest city in Europe, which also the straightest road in Europe (nearly 8km)

Rob Hayles
Former Great Britain cyclist on BBC Radio 5 live sports extra

"It's hideous out there. The climb itself is pretty steep at the bottom, above 9% gradient in places. About a third of the way up it hits another big section of more than 9%. I'm feeling sorry for the riders but that's probably because I'm feeling a bit sorry for myself having done the climb this morning. I had a few stops to top the bottle up from a few helpful Brits on the climb."

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Result of KOM price at Col de Palaquit

1. Alessandro De Marchi (Cannondale), 10

2. At 1.15: Jan Bakelants (OPQS), 8

3. At 1.40: Luis Maté (Cofidis), 6

4. At 2.40: Jérôme Pineau (IAM), 4

5. At 2.45: Joaquim Rodriguez (Katusha), 2

6. Thibaut Pinot (FDJ), 1

BBC Radio 5 live sports extra

While all that has been going on, Rob Hatch and Rob Hayles have hit the airwaves. Want to know how tought today's final climb is? Tune in and I'm sure they'll tell you. The coverage is website only today.

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The main bunch, which includes Vincenzo Nibali, comes over the summit practically together, although King of the Mountains leader Joaquim Rodriguez tries to take fourth over the top for four extra points. He is beaten by IAM's Jerome Pineau and has to settle for two.

Bakelants reaches the summit and rides straight to a waiting Omega Pharma - Quick-Step mechanic who has another bike for him. Is it a tactical switch, or a necessity? Either way, Bakelants is not hanging around and he is soon back pedalling.

Could this be trouble for race leader Vincenczo Nibali? A couple of his Astana team-mates, including decent climber Michele Scarponi, have already been shelled. Can anyone keep the hurt on in the peloton to try and isolate Nibali on the final climb?

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De Marchi is within 1km of the summit of Col de Palaquit. Shoulders rolling, Bakelants is just 35 seconds behind him and here comes Mate, 25 seconds further back, shoulders rolling but not quite as pronounced as the man he is chasing.

Cannondale's De Marchi is out of his saddle putting in one last effort to be the first rider over the summit and he does just that to pick up 10 King of the Mountain points. He tucks straight into an energy bar as he starts the descent.

Image source, Mark Cavendish

While his fellow sprinters are toiling in the Alps, Britain's Mark Cavendish, who crashed out on stage one in Harrogate, has been busy getting himself race ready again.

Mark Cavendish:, external Last session for a while in the Isle of Man Hyperbaric Chamber. The facility & staff have been incredible. Thank you!

Poor old Blel Kadri has bonked. The Frenchman, who was in the lead a couple of kilometres ago has dropped like a stone straight through the peloton. The TV camera goes up alongside Kadri but he doesn't even have the energy to flash a smile. He is hurting.

De Marchi continues to plough a lone furrow up the Col de Palaquit. He takes a bottle from his team car, squirts its contents over his head but then drops it before he has time to sling any down his throat.

No time to stop and pick it up though. He has 5km to the summit but his exertions are paying off as he moves 2'30" clear of the peloton.

Bakelants is about one minute adrift of De Marchi and he is being chased by Luis Mate of Cofidis. Everybody else is back alongside the yellow jersey, or further down the mountain.

BBC Sport's Tim Peach:, external And we have a full commentary team! @robhatchtv has arrived. On air on the @BBCSport website at 3!

John in London, via text on 81111: Team Sky have some very good climbers that have been losing a surprising amount of time until now. Lack of fitness or saving themselves for Porte today?

Team Sky's Geraint Thomas has unzipped his jersey and just stomped on his pedals to shift himself to the front of the peloton. Thomas is flanked by Spaniard Mikel Nieve, who is Sky's other key helper for Richie Porte in these mountain stages.

Race leader Vincenzo Nibali looks untroubled by all the posturing ahead of him. With the lead he already has, he can afford to ride defensively today and just cover any attacks.

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A brave and bold move by De Marchi. Has the Cannondale rider got eyes on the big prize? There are 50 King of the Mountain points on offer for the first man to Chamrousse.

He has 18 points so far, if he reaches the top of Col de Palaquit first he will pick up 10 more. He can't stay clear to Chamrousse though...can he?

Di Marchi's lead is 83 seconds.

The front of the race has split wide open with AG2R rider Blel Kadri and Omega Pharma - Quick-Step Jan Bakelants taking up the pace.

They are not having it their own way though because here comes Alessandro De Marchi and the Italian, who had been dropped by the break, has benefitted from having a quick breather and he has ridden straight past Kadri and Bakelants.

Drew Stephenson, via text on 81111: Tejay van Garderen arguably the best time triallist of the GC contenders, but not 4 mins better.

The sprinters are tumbling out the back door of the peloton at an alarming rate. Bryan Coquard of Europcar and Lotto-Belisol's Andre Greipel are forming the Grupetto - it's going to be a long ride home for the quick men.