Contador is out on course - the two-time champion has fared well in grand tour time trials in the past - can he move up a place on GC? He needs 13 seconds to surpass Barguil.

Image source, Reuters

The polka dot jersey Warren Barguil - ninth on GC - rolls down the start ramp to rapturous applause.

Good man. He's wisely opted against the dreaded polka dot shorts, going for an all red lower half instead.

Image source, Reuters

First shot of Chris Froome, headphones in, warming up in his full yellow skinsuit.

The Briton is off at 16:04 BST. A fourth Tour title the prize at the end of the day.

Chavanel loses one place in the final third of the stage to finish seventh as it stands.

Image source, Reuters

So, Alberto Contador is about to head off - the first of the top 10 riders on general classification to start.

These will be the final 10, in reverse order, to head down the ramp...

General classification after stage 19:

1. Chris Froome (GB/Team Sky) 83hrs 26mins 55secs

2. Romain Bardet (Fra/AG2R La Mondiale) +23secs

3. Rigoberto Uran (Col/Cannondale-Drapac) +29secs

4. Mikel Landa (Spa/Team Sky) +1min 36secs

5. Fabio Aru (Ita/Astana) +1min 55secs

6. Dan Martin (Ire/Quick-Step Floors) 2mins 56secs

7. Simon Yates (GB/Orica-Scott) 4mins 46secs

8. Louis Meintjes (SA/Team UAE Emirates) +6mins 52secs

9. Warren Barguil (Fra/Team Sunweb) +8mins 22secs

10. Alberto Contador (Spa/Trek-Segafredo) +8mins 34secs

A big cheer for Nairo Quintana as he goes down the ramp.

"It has not been his Tour," says Rob Hayles. "I don't think we will see him ride the Giro and Tour in the same year again."

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And here's what everyone's aiming for today - a spot on the podium. Hopefully it'll be less cloudy by the time everyone's had their go.

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Two more excellent suggestions.....

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French veteran Sylvain Chavanel is putting in a decent ride - he's just gone through the second check in sixth place, 26 seconds down on Bodnar.

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1. Maciej Bodnar (Pol/Bora-Hansgrohe) 28mins 15secs
2. Michal Kwiatkowski (Pol/Team Sky) +1sec
3. Tony Martin (Ger/Katusha-Alpecin) +14secs

Team Sky rider Luke Rowe, speaking to BBC Radio 5 live sports extra: "Chris knows he's got a big task ahead of him - a lot of people are saying he's already won the Tour de France but that's a million miles from true.

"He's got high class guys not far behind him in the GC so he's got a lot to do today.

"That said, I've got full confidence in him and he's one of the best time triallists in the world. I think he can do it and have yellow tonight but it's not over until the fat lady sings."

Chris Froome is the last man out at 16:04 BST.

Warren Barguil as just been named as the most aggressive rider for this year's Tour de France.

The Frenchman will take to the podium twice in Paris then, also having wrapped up the polka dot jersey.

Thomas de Gendt will be spitting. All those kilometres in breakaway and now absolutely nothing to show for it.

Rob Hayles
Former GB cyclist at the Tour de France

The out-and-out time triallists really do not like the climbs. It doesn't really suit someone like Tony Martin, who likes it fast and open when they can turn on the power.

Couple that with the fact that we are three weeks into the bike race and that can have an effect on the legs. Some react better than others.

If you good too deep, too soon, then when you reach that climb, bang, you're gone.

Image source, EPA

Roglic finally comes home in 10th.

Never really happened for the Slovenian, even before he suffered some form of mechanical issue on the climb.

Yet another favourite fails to better Bodnar's time. Will anyone beat it?

Daniel Greenfield: If a rider catches his minute man why dont they ever draft them, preserve energy and then cash that effort in on the last 5km?

In short, because drafting behind another rider is against the rules in a time trial and any rider who does it is liable to receive a time penalty or be disqualified.

Thomas de Gendt has just finished the course in a touch over half an hour.

That time trial must've felt strange for the Belgian - no way of getting in a breakaway today, unlike pretty much every other day on this Tour for him.

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Roglic in a lot of trouble on the climb - having to get pushed uphill by a mechanic.

Not sure if he had to change bikes or possibly a dropped chain.

His hopes of victory, which already looked to have faded, are nonexistent now.

John-Paul McCrone: Welcome to the Jungels.

Excellent.

Dan: "Henao Henao don't dream it's over" crowded house. "Kittle be lonely this Christmas" mud. "Landa Hope & Glory" by the queen

Anonymous: How about the Keane/Lily Allen ballad 'Somewhere Only Pinot'?

Not sure Roglic does have enough in the tank - he's through the first check 25 seconds down on Bodnar.

Orica's Daryl Impey has had a decent ride though - the South African rolls in 19 seconds behind Bodnar and into fourth place.

Team Sky's Luke Rowe, speaking to BBC Radio 5 live sports extra: "It's a tough time trial with wide boulevards and there are plenty of times to put the power down.

"It can be lost on one or two bends but certainly not won there so stay calm on the technical sections and then, on the long boulevards, put that power down."

Image source, AFP