Postpublished at 15:03 British Summer Time 30 June 2021
Stefan Kung has 1km to go.
Stage 5 - 27.2km individual time trial from Change to Laval
Key day for overall contenders
Can Mathieu van der Poel retain leader's yellow jersey?
Geraint Thomas posts 33:18
Reigning champion Tadej Pogacar wins in 32:00
Jack Skelton
Stefan Kung has 1km to go.
Richie Porte goes second quickest at the second time check - 23 seconds back on Stefan Kung.
Stefan Kung has just blasted past Pierre Rolland, who started three minutes before him.
Stefan Kung goes quickest at the second time check - by 25 seconds!
The Swiss rider is flying. Barring an accident, he'll be the new leader shortly.
Stefan Kung blitzes past the rider who set off 90 seconds before him.
Richie Porte has laid down a strong time through the first check - fourth quickest overall there.
Mattia Cattaneo goes quickest overall - around six seconds quicker than Mikkel Bjerg.
The Italian posts 32:55. How long will he occupy the hot seat?
Ireland's Dan Martin has just told ITV4 that conditions are very tricky out there, with wet patches on corners proving especially tough.
Cattaneo looks to have clawed that lost time back on the final section.
He is almost neck and neck with Bjerg's time with 2km to go.
Interesting - both Cattaneo and Powless have been unable to maintain their fast starts by the second time check. Bjerg is still quickest there.
Meanwhile, Stefan Kung sets the quickest time at the first time check - 10:49, nine seconds quicker than previous best Powless.
Ineos Grenadiers' Richie Porte gets under way.
The Australian is usually a strong TT rider. He has dry roads and a chance to move up the GC as well.
Can that spur Porte on to an impressive showing today?
American Neilson Powless has just bettered Mattia Cattaneo's first time check mark by five seconds.
Mikkel Bjerg might've felt that he had a chance of a shock stage win earlier, had the rain held.
It looks like there will be plenty of quicker times to come today now.
Cavendish's team-mate Mattia Cattaneo has gone through the first time check six seconds quicker than current leader Mikkel Bjerg.
The roads look to be drying up as well.
One of the favourites for the stage Stefan Kung has just rolled down the start ramp.
We're in for one of the best TTs of all time if it provides a story as good as yesterday's stage...
Mark Cavendish claimed his first Tour stage win in five years and 31st overall in a thrilling sprint finish.
It also saw the British rider move into the green points jersey and he honoured it in fine style today - posting a strong time of 35:24.
Britain's four-time Tour champion Chris Froome found himself in the odd position of being one of the first riders down the ramp and posted a respectable time of 36:20.
"Things are improving," he told ITV4.
"Day by day I'm feeling better and hopefullly that will come around a bit more before the mountains."
The route looks flat on the stage graphic but it's certainly not - there are plenty of climbs that will suit punchy riders who can kick up sharp gradients comfortably on their time trial bikes.
That sounds exactly like Tadej Pogacar and how he won last year's race by overhauling Primoz Roglic on the penultimate day.
Can he use this TT to put his fellow Slovenian into more trouble early in this year's edition?
Those are the stage contenders and general classification riders to look out for today.
Britain's Simon Yates is currently out on the course, but isn't trying to make up time for GC ambitions. He's at this year's Tour for stage wins so losing time today could actually benefit him being allowed to go up the road during the rest of the race.
14:15 - Mattia Cattaneo (Ita/Deceuninck-QuickStep)
14:31 - Stefan Kung (Swi/Groupama-FDJ)
14:39 - Richie Porte (Aus/Ineos Grenadiers)
15:12 - Primoz Roglic (Slo/Jumbo-Visma)
15:16 - Geraint Thomas (GB/Ineos Grenadiers)
15:32 - David Gaudu (Fra/Groupama-FDJ)
15:36 - Nairo Quintana (Col/Arkea-Samsic)
15:38 - Enric Mas (Spa/Movistar)
15:40 - Tadej Pogacar (Slo/UAE Team Emirates)
15:42 - Wilco Keldermann (Ned/Bora-Hansgrohe)
15:44 - Wout van Aert (Bel/Jumbo-Visma)
15:46 - Richard Carapaz (Ecu/Ineos Grenadiers)
15:48 - Julian Alaphilippe (Fra/Deceuninck-QuickStep)
15:50 - Mathieu van der Poel (Ned/Alpecin-Fenix)
Stefan Bissegger's EF team-mate Magnus Cort has just posted an excellent time of 33:07 to go second overall, just six seconds back on Mikkel Bjerg.
I don't think anyone expected that from the Dane.
1. Mathieu van der Poel (Ned/Alpecin-Fenix) 16hrs 19mins 10secs
2. Julian Alaphilippe (Fra/Deceuninck-Quick-Step) +8 secs
3. Richard Carapaz (Ecu/Ineos Grenadiers) +31secs
4. Wout van Aert (Bel/Jumbo Visma) Same time
5. Wilco Kelderman (Ned/Bora-Hansgrohe) +38secs
6. Tadej Pogacar (Slo/UAE-Team Emirates) +39secs
7. Enric Mas (Spa/Movistar) +40secs
8. Nairo Quintana (Col/Arkea Samsic) Same time
9. Pierre Latour (Fra/TotalEnergies) +45secs
10. David Gaudu (Fra/Groupama-FDJ) +52secs
A steady rain has been falling from about halfway through the startlist and TV pictures have picked up that Stefan Bissegger almost crashed negotiating a corner.
To have covered the course just 21 seconds down on Mikkel Bjerg's time was very impressive then, with Bjerg having posted that mark in the dry.