Two riders who won't be contesting today's brutal stage, having already crashed out of the race, are Richie Porte and Geraint Thomas.

The former Team Sky team-mates are in good form, though. It's especially good to see Porte smiling after the BMC leader's horrible crash on Sunday's stage nine.

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Right, the summit of this fourth category climb is coming up - who fancies grabbing a mountains classification point?

Answer: Thomas de Gendt. The Belgian Lotto Soudal rider pops off the front to pick up the only point on the Cote de Capvern.

Talking of our commentary team - there on BBC Radio 5 live Sports Extra from 14:00 BST today and you'll also be able to listen by clicking the tab at the top of this page.

While we're waiting for the manic second half of this stage, why not also catch up with the latest BeSpoke podcast, as messrs Brotherton and Hayles are joined by OJ Borg to recap Stage 11?

You can watch by clicking the link below or here. And you can download all the podcasts so far here.

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A spot of rain starts to fall as the break and peloton head up this not-too-challenging fourth category climb.

Looks lovely at the finish at Peyragudes, though. Our commentary team of Simon Brotherton and Rob Hayles have even donned their sunnies.

Image source, BBC Sport

Team Sky are on the front of the peloton, looking to keep Chris Froome completely out of even any hint of danger before the big climbs to come late on.

They're happy to right at tempo - of course - as the breakaway's lead moves out to 4'22'' as they approach 150km to go.

With the likes of Cummings and De Gendt in the break, that leading group of 12 has a good chance of staying away for a long time.

They've just upped their advantage to four minutes over the peloton, with 156km to go.

Well, speaking to ITV4 before the start of the stage, Steve Cummings admitted he would try to get in the break today.

"It's a good flat start and the final is really hard, it's right on the limit," he said.

"It depends on the composition of the breakaway but I have to try.

"I've read the book about Tom Simpson, we know a lot about his story in British cycling history. It was a tragic incident.

"He was one of the first British cyclists I was aware of so it would be good to go and do a good ride today."

The circumstances around Tom Simpson's death obviously make him a complex and controversial figure.

The 50th anniversary has largely gone unmarked by this year's Tour - a move criticised by some, including journalist Jeremy Whittle who told our commentary team yesterday that Tour organisers should have done more out of respect for a rider who died during the race. The route does not go over the Ventoux this year.

It's difficult. The Tour perhaps does not want to be seen to explicitly honour a rider guilty of doping. Yet given the various former riders caught up in doping scandals during their careers that are still welcome at the event, that stance is seen as hypocritical by others.

Regardless, Simpson was a hugely influential figure for many riders, especially British ones. Sir Bradley Wiggins went out on an ultimately unsuccessful long solo attack in honour of the 40th anniversary of Simpson's death at the 2007 Tour.

Is Cummings trying something similar today?

Image source, Getty Images

The break continues to roll through, working together well and now have a lead of almost three minutes, with around 171km left to race.

Could Cummings be looking for victory today to honour the memory of Tom Simpson?

Simpson was the first British rider to wear the leader's yellow jersey, having done so at the 1962 Tour de France.

In 1965, he won the World Championships and in 1967 he was targeting overall victory at the Tour.

He fell ill during that Tour and had fallen down the standings before the 13th stage that crossed the legendary Ventoux climb.

He started the stage on a day where temperatures exceeded 30°C but struggled on the brutal climb, falling around one kilometre from the summit,

Simpson got back on his bike but collapsed again and died, 50 years ago today.

A post-mortem revealed that Simpson had both amphetamines and alcohol in his system.

Image source, Getty Images

Steve Cummings' team-mate Mark Cavendish thinks his compatriot could be in contention for today's stage...

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Confirmation that there are 12 riders in the breakaway group that has gone away.

They are: Cyril Gautier (AG2R), Imanol Erviti (Movistar), Koen de Kort (Trek), Stefan Kung (BMC), Diego Ulissi (Team UAE Emirates), Steve Cummings (Dimension Data), Marcel Kittel (Quick-Step), Jack Bauer (Quick-Step), Nils Politt (Katusha-Alpecin), Thomas de Gendt (Lotto Soudal), Michael Matthews (Sunweb) and Julien Simon (Cofidis).

Plenty of teams have missed the break then, but the peloton seems to be happy to let this one go away - the break have a gap of over two minutes already.

That's not gone well for Sunweb, mind. Warren Barguil was desperate to get in the break to win mountain classification points, he didn't get there so they settled for putting Michael Matthews up there, only for Marcel Kittel to make it across too.

Kittel has a team-mate with him as well. Can't see the German losing the intermediate sprint later on.

OK, a promising break of around 10-15 riders has gone up the road.

A couple of names to note up there - Britain's breakaway specialist Steve Cummings and the Belgian rider Thomas de Gendt, who has won similarly tough stages in the past.

Michael Matthews in there too, looking for green jersey points, only to look behind him and see that Marcel Kittel - who leads that competition by 133 points - has made it across too.

Britain's Steve Cummings - a breakaway specialist - has popped up near the front.

The Dimension Data man has been quiet in this Tour, often happy to ride at the back of the peloton, biding his time.

Could today be his day? Is he perhaps planning an attack to mark this significant day in British cycling history?

Today is the 50th anniversary of the death of British cyclist Tom Simpson on Mont Ventoux during the 1967 Tour de France.

Tony Gallopin is the latest Lotto Soudal rider to come to the front and try to force something.

Nothing happening yet - plenty of brief thrashes off the front but no break has formed and it's all calmed down for a while.

Just 200km to go!

Sure enough, that three-man group of McCarthy, Irizar and Petit are quickly swallowed up.

Lotto Soudal's Tim Wellens comes to the front and Sunweb's Warren Barguil jumps on to his wheel.

The Frenchman is absolutely desperate to get in the break today and claim more points in the mountains classification.

He's over 14 minutes down on Chris Froome so would be allowed to go by the overall favourites but the others looking to get in the break are marking him out at the moment.

A three-man group has gone up the road - Jay McCarthy (Bora-Hansgrohe), Maikel Irizar (Trek-Segafredo) and Adrien Petit (Direct Energie).

They've got a slight gap and the front of the peloton is somewhat disorganised but I don't think they stand much of a chance staying away on their own.

They'll need a sizeable group to come across and join them soon.

As expected, the pace is fairly frantic early on as a breakaway group try to get establish themselves.

Sunweb's Warren Barguil, in the polka-dot mountain classification jersey, tries to get in an early move but doesn't get the help required, drifting back down the peloton.

So, before they get outside the city, a word on Pau.

It's one of the most common destinations for the Tour to visit, due to its excellent set-up and proximity to the Pyrenees. You'll often find one of the rest days based there.

And that's where the madness can start. Pau has been the location of many notorious moments in Tour history.

It's in Pau where Alexander Vinokourov's positive test for blood doping was revealed in 2007. Also in Pau in 2007, race leader Michael Rasmussen faced questions over whether he had lied about his whereabouts earlier that year - a thread that unravelled in his own team Rabobank withdrawing him from the race.

It's in Pau in 2010 where Alberto Contador gave the urine sample that retured a positive test for clenbuterol, which eventually led to his being him stripped of that year's title.

And in Pau in 2012, Frank Schleck - who took third in the 2011 Tour - tested positive for a diuretic.

No scandal this year, fortunately, as the riders exit this iconic Tour location on the way to the Pyrenees.

The peloton has already started the roll-out from Pau.

The southern French city has a famous - and sometimes infamous - place in Tour de France history. More of that in a second.

It's a fairly lengthy neutralised section to start this stage but once the flag goes down, expect plenty of riders to put the hammer down trying to get into a break.

The first 100km of the stage are relatively straightforward but any break that does form will have to hang on in the brutal second half.

Here's what they're tackling today...

Image source, Le Tour