This live event has finished
- Trowbridge pilot John Jackson competes in Sochi
- British notch up 1:50.53 overall after a first run of 55.26 and a second run of 55.27
- GBR1 move up from tenth to seventh, 0.18 off the bronze medal position
Thanks for following our coverage of the first day of the men's four-man bobsleigh at Sochi 2014.
The final two heats take place tomorrow on the final day of the games, with Jackson's crew getting stuck in to the third heats from 9.30am.
Log on wiltshiretimes.co.uk/sport bright and early tomorrow morning for live updates of all of the action as it happens.
The sleds between 20th and 30th position after the first runs are now taking to the ice but they're no expected to affect things at the top of the standings
Russia 1 hold on to their lead as the notch up 55.37 for that second run.
Their lead has been cut to just 0.04 seconds and Jackson and co, who have moved up from tenth to seventh this evening, are 0.34 behind.
And the Trowbridge pilot and his team are just 0.18 seconds off the podium
Germany 1 notch up 55.47 to move into second place
The top two sleds left to go
USA 1 come home in 55.47 as Latvia 1 still lead
Lativa 1 are the current leaders as USA1 get ready to push off
Germany 3 narrowly sneak ahead of Jackson's crew by just 0.05 seconds. They go second
0.01..... Tomorrow is gonna be AWESOME!!— @BexGBbobsleigh 22 February 2014
Watching the Bobsleigh, there's @paulawalkerGB starting a mini Mexican wave and then tweeting again. Atmosphere must be weird after crash.— @motti82 22 February 2014
For a moment, the Russians hadn't managed to get in front of Jackson's men but they're finally knocked off their perch.
Russia 2's 55.41 is just 0.01 seconds ahead of GBR1
Huge progress from Jackson and co this evening - they're guaranteed to be within the top seven going in to the second day of competition
Russia 2 are up next
And Germany 2 aren't fast enough to knock GBR1 off the top!
The Germans come home in 55.43 and go into third, +0.05 behind Jackson's crew
So cute how @paulawalkerGB cheers for her @JohnJacksonGB #Sochi2014 #bobsleigh http://t.co/DUXxLQnVLq— @LisetteThoene 22 February 2014
And the action gets back underway as Germany 2 take to the ice next
So there's a slight delay as the officials check the state of the track after Canada 3's crash.
Germany 2 are scheduled to slide next
Errrr why is my John Boy doing all the work!!! http://t.co/sOcqS9rRk6— @paulawalkerGB 22 February 2014
That was an absolutely spectacular crash and the Canadian quartet look pretty shaken up - but not seriously injured.
Their sled was kicked up going in to corner 12 and whistled down the remainder of the track on their right flank
It's bad news for Canada and I'm sure they won't be too pleased to see another team slip up but that is good news for the Brits
Canada 3 crash!
And impressive second run from Jackson and his team-mates look like it may just push them up the leaderboard at the halfway stage.
How far? Let's see!
And Switzerland 1 come in 0.02 seconds slower than GBR1!
Jackson's quartet come home in 55.27 to head to to the top of the leaderboard.
That's 1:50.53 overall
GBR1 are still stretching their lead
It's a world class start of 4.81
Jackson and his crew gather their nerves and push off down the Sochi track
John Jackson's GBR1 are up next!
Canada 2 come home in 55.43 to take 0.31 lead overall
Canada 1 slip to third place after a run of 55.70
Canada 2 up next...
Netherlands 1 are 0.03 behind USA 2 after one of the slowest second run times we've had so far (55.57)
Latvia 2 (55.52) and USA 2 (55.48) have both clocked in. Three more sleds to go before Jackson's crew return to the top of the track
France (55.68), Italy (55.73) and Russia 3 (55.53) have all gone down for a second time.
Just a reminder that Jackson's quartet were 0.44 off the lead after their first run and all of the crews to hit the track again so far have improved on their times
Jackson and his crew complete their first run at the Sanki Sliding Centre today.
Great Britain's second sled, driven by Lamin Deen, slip 0.09 seconds behind the Czechs, despite a great run of 55.60
Great Britain 2 are next up - and off they go!
The bottom-ranked sled improve on their first run as they come home in 55.47
And the second runs are underway in Sochi
Czech Republic 1 will be setting off first to kick off this evening's second heat
So there's not long til Jackson's four-man crew return to the ice.
The second runs are due to begin shortly and the Trowbridge pilot's sled will be pushing off 11th as we go in reverse order of the leaderboard
That's it. All the crews are down. Russia 1 lead the way,followed by Germany 1 and USA 1.
Jackson and GB 1 are 10th at the moment and they'll be keen on a good second run to get them right up into the thick of things.
Dan Barnes will be back with you from 6pm for the start of the second run.
@TeamGB @JohnJacksonGB @team_deen well done guys #GoTeamGB #Sochi2014— @AFC_Harry34 22 February 2014
After Heat 1 of the 4-man Bobsleigh, @JohnJacksonGB's GBR1 are 10th fastest and @team_deen's GBR2 are 19th. Heat 2 starts at 6pm. #GoTeamGB— @uk_sport 22 February 2014
Let's c some #Twitterlove 4 @JohnJacksonGB @StuBensonGB @JoelFearon6 @Bruce_Bobsleigh @team_deen @ShapedNotFaded @benthebounce JohnBaines.🇬🇧— @L_Livingstone1 22 February 2014
So, at this stage, it's looking very much as though Jackson and co will be among the last 10 crews to go off in the second run. Plenty still to play for. A reminder that second run starts from 6pm and you can follow it here.
posh and becks of the bobsleigh world #TeamGB #bobsleigh @JohnJacksonGB @paulawalkerGB— @walterrose1847 22 February 2014
It's as you were in the top 10 now as some of the less-fancied crews make their way down the track at the Sochi Sliding Centre.
@JohnJacksonGB and co did a flying start! And top cheering from the folks behind them at the start— @antinbath 22 February 2014
@JohnJacksonGB good luck to you all 😄🏆— @TinaMcGuff 22 February 2014
Couple of bumps on the way down for GB2 and they are 1.09 behind the Russians and stay 18th overall. We've got 12 crews to go in this first run.
We're all set for GB 2........ Italy started 17th and stay there.
Italy 1 next, before the GB 2 crew of Lamin Deen come down.
None of the crews post-Jackson have been able to go quicker. Perhaps a reflection of track conditions.
A solid first run for @JohnJacksonGB's GBR1 team puts them into 10th place - 0.44 seconds off the lead. GBR2 will race shortly. #GoTeamGB— @uk_sport 22 February 2014
Half the crews are down and it's all pretty tight. Jackson's GB crew are 10th, but less than half a second off gold.
They are 0.44 back in 10th. Probably slightly disappointed with that run but a long way to go yet.
Good start. 4.79, equal to the Russian start.
Switzerlan 1 come down in ninth spot. Here come Great Britain 1........
Canada 3 are actually the best of their country's crews at the moment in eight. Two more to go efore Jackson goes.
Get ready to cheer @JohnJacksonGB @StuBensonGB @JoelFearon6 @Bruce_Bobsleigh and gorgeous @George4ManGb #meatwagon #GoTeamGB 🇬🇧🇬🇧 #bobsleigh— @L_Livingstone1 22 February 2014
Good luck @JohnJacksonGB and team. Go for gold guys.— @GoodLuckTeamGB 22 February 2014
Still nobody can displace the Russians as Germany 2 come down in 55.15 for seventh spot.
@JohnJacksonGB We would like to wish you and the boys all the very best for tonight. We will be cheering you on from a wet and windy Devon— @madmifff 22 February 2014
Latvia 1 are seventh down, but they are fifth quickest with 55.10.
@JohnJacksonGB @StuBensonGB @Bruce_Bobsleigh @JoelFearon6 @team_deen @ShapedNotFaded @benthebounce It's time to show the world who's boss!— @VivereB 22 February 2014
Come on @JohnJacksonGB and @team_deen! Slide it like you stole it! @GBBobsleigh— @CatGreenRacing 22 February 2014
Ready for the thrill. It's Men's #Bobsleigh day. #GoTeamGB @JohnJacksonGB @ThomasLyte #support @TeamGB #Sochi2014 #GoTeamGB— @ThomasLyte 22 February 2014
Canada 1 are well adrift at 0.68 seconds off the pace.
Germany 3 come down, but they are +0.24 adrift.
Good news for the Russians, who go into the lead with 54.82.
Russia 1 comes next, featuring the two-man Olympic champion Alexander Zubkov.
USA 1 are next and they are 0.01 behind.
Here we go...............
Germany 1 are first down in 54.88. A reminder Jackson and crew will go 12th.
To underline the competitive naure of this event though, Jackson is going to have to beat off some pretty intense competition.
Rivals for a medal include American reigning Olympic champion Steven Holcomb, reigning world champion Beat Hefti of Switzerland, and newly-crowned Russian two-man champion Alexander Zubkov.
The Royal Marine is in no doubt about the extent of his crew's task.
"To be on the podium in Sochi we've got to beat the current Olympic champion and current world champion.
"To get in the top six we've got to beat people who are consistently on the podium so that's the challenge we are up against."
Great Britain would love to round off a successful Sochi Games by landing another medal and, after finishing fifth in the World Championships last year, Jackson certainly has the pedigree, but the man himself is keeping calm.
Whatever the result, we are going to hold our heads up high and give it everything we can in true British fighting spirit.John Jackson
Jackson, whose partner Paula Walker was 12th in the women's two-man event earlier this week, was third fastest in the sixth and final training heat on Friday.
The Paxcroft Mead pilot's crew have completed a series of fast training times this week, including the fastest in second official practice on Thursday, following up on the successful World Cup campaign this winter which saw them claim one podium finish in Lake Placid and a European Championships silver medal.
It's fair to say a bit of buzz has developed around Jackson's crew this week - and not just because of his remarkable recovery from a ruptured Achilles sustained last summer to even make the Sochi start line.
The first of four runs to decide the medals gets under way from 4.30pm British time with pilot Jackson's quartet - also including Bruce Tasker, Joel Fearon and Stuart Benson - the 12th starters.
Heat two goes off from 6p, with the final two runs going from 9.30am and 11am tomorrow morning.
GOOD afternoon and welcome to our coverage of the Olympic four-man bobsleigh as Trowbridge's John Jackson aims to pilot Great Britain 1 to a first medal in the event since the 1998 Games in Nagano.
We'll bring you the action from the Sanki Sliding Centre, plus any reaction from Jackson after today's two runs.Leave us your comments below the live blog or send us a tweet using the hashtag #WTJacksonLive