08:00 Welcome to AUTOSPORT Live's coverage of the second winter Formula 1 test of 2010 at Jerez.

08:05 The cars are currently heading out for their installation laps, although timing screens are not functioning at present.

08:09 This morning has already seen the unveiling of Red Bull's new RB6, the car it hopes will build on the form that saw the team mount its first title challenge last year.

08:11 The RB6 is one of the cars that has already been out for an installation lap, with Mark Webber given the task of putting the first laps on the new machine.

08:13 As well as marking the new Red Bull's debut, today's test is the first chance to see the Force India VJM03 - which was revealed yesterday - in action, and the first run in Formula 1 company for one of the new teams, as Virgin joins the fray with its VR-01.

08:14 The media is gathering in the paddock ready for the Red Bull briefings, with the drivers and leading team personnel set to give their thoughts on 2010 and the RB6.

08:18 The weather at Jerez has already become a hot topic, with rain expected for much of the week. But today's running has started on a dry track.

08:19 Webber's first thoughts on the Red Bull RB6, thanks to eddstrawF1: "The car looks great. I'm really looking forward to what it can do."

08:20 Looks like the car continues the trend for longer chassis in 2010 too: "It's a limousine! We had to make it longer."

08:23 Red Bull missed the first test of the winter at Valencia last week, preferring to spend more time fine-tuning the design in the factory, but Webber does not think this will be a problem: "Valencia is not the best track in the world for characteristics. We'd have liked to be there but I don't think we lost too much."

08:35 Red Bull boss Christian Horner is telling the media in the Jerez paddock, including eddstrawF1, that the RB6's development programme is already underway: "Like all teams we have quite an aggressive development programme. We have components we will introduce in the next couple of tests."

08:36 With most teams just doing installation runs so far, only two drivers have set flying laps in the opening half hour. Sebastien Buemi is fastest for Toro Rosso on 1m22.164s, with Sauber's Kamui Kobayashi on 1m23.789s.

08:41 The times are coming down as the serious running gets underway. Buemi is still fastest on 1m21.031s, with Nico Rosberg now second for Mercedes, 0.6s adrift.

08:41 Nico Hulkenberg, Fernando Alonso, Vitaly Petrov and Mark Webber have also started their first proper runs.

08:43 Here is the full driver roster for the next four days of testing:

Jerez test's driver line-up

08:50 As the Red Bull briefing continues in the paddock, Adrian Newey reveals how close the team came to switching to Mercedes power: "We started looking at an installation for the Mercedes engine. There was a bit of a delay as we looked at both packages."

08:52 Rosberg now puts Mercedes at the head of the order with a 1m20.927s lap, while Jenson Button starts his day for McLaren.

08:54 Mercedes had been looking at revising its weight distribution in light of what it learned during the opening test at Valencia last week, so its Jerez performance should be more indicative of its true form.

09:02 Sebastian Vettel's first thoughts on the RB6, courtesy of eddstrawF1 at the Red Bull Racing media gathering: "The cars don't look completely different to last year and it's more of an evolution of last year's car."

09:03 The predicted rain has just started falling on Jerez.

09:05 The forecast had been for showers towards the end of today's running, with Friday currently expected to be the wettest day:

Jerez weather forecast

09:07 Times after the first hour: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s.

09:08 Everyone except Liuzzi has returned to the pits, and all bar Virgin Racing's Timo Glock managed to set times before the shower started.

09:09 @eddstrawF1: "The Virgin hasn't been out yet... new parts arrived late last night. But it is expected out in the next 20 minutes, weather allowing."

09:11 Williams's Hulkenberg completed the most running in the dry hour, notching up 17 laps. Rosberg and Alonso both managed 11, while Liuzzi is now on lap nine as he stays out in the damp conditions.

09:13 Virgin update from eddstrawF1: "Latest on the Virgin is that it might be a bit longer than 20 mins before it's out - but they are confident that it will be on track soon."

09:15 The track remains damp, with an air temperature of just 11 degrees and a wind speed of 2mph. Liuzzi has returned to the pits after 10 laps and the circuit falls silent.

09:17 But not for long, with Webber now setting out to evaluate conditions in the new Red Bull.

09:21 Red Bull the latest team to experience some technical glitches with its launch coverage, @RedBullF1spy: "Trying to stop the web guy from jumping under a truck. Apparently things aren't good on the technical/website front. Send him your best..."

09:24 Hulkenberg heads out on the still damp track as well.

09:29 The big question in the Jerez media centre this morning: just what does McLaren's latest sensor contraption do?

09:29 And here it is from the front...

09:31 Webber has now logged 15 laps in the new Red Bull, nine of them in the wet. Hulkenberg is back in the pits.

09:33 The wet weather seems to be putting spectators off, with the current crowd smaller than the opening test at Valencia attracted last week. A smattering of spectators occupies the main stand.

09:34 Although the rain has been relatively light, enough has fallen to make the track damp and create small spray trails behind the cars.

09:37 Now Hulkenberg is back out alone as Webber returns to the pits.

09:39 Button has also been out briefly to sample the track conditions, this time without the odd sidepod appendage.

09:44 Hulkenberg's mileage on the damp track means he now has 24 laps under his belt, the most of the session so far.

09:52 Ferrari has tweaked its schedule to take the rain into account, @insideferrari: "It is raining so we decided to anticipate some work scheduled for the lunch break. The car will remain in the garage at least one more hour"

09:52 Kobayashi, Button and current pacesetter Rosberg are joining Hulkenberg out on track.

09:54 @eddstrawF1: "Just checked in with Force India: 'All OK. Working through general installation checks this morning and then balance checks this afternoon'"

09:55 Hulkenberg returns to the pits as Webber comes back out for more wet track mileage.

09:57 Times still a long way off the earlier dry pace, with Rosberg currently lapping in 1m29.4s and Webber on 1m31.6s.

09:59 Button is fastest right now, lapping in 1m28.879s last time around.

10:00 With the second hour having been wet throughout, there is no change to the standings at 11am local time: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s.

10:02 Now Rosberg has got down to 1m28.9s, with Liuzzi heading out to make a five-car group on the still soggy track.

10:07 A McLaren spokesman tells AUTOSPORT that the curious structure seen on Button's car this morning is part of the team's programme for measuring aerodynamic flow structures while on-track:

"Given the limited amount of testing that teams have been permitted over the past two seasons, as a team we feel it's necessary to put as much emphasis as we possibly can on accurately measuring the flow structures we encounter at the track so that we can match them to the flow structures we are able to simulate in CFD and the windtunnel back at the factory."

10:09 The team underlines that there is no need for "alarm bells", and that this is just "normal engineering work".

10:18 Rain falling harder now at Jerez. Buemi and Kobayashi now the only cars on track.

10:20 Hulkenberg, Liuzzi and Webber rejoin the fray, while Buemi heads back to the garage.

10:23 Lotus is present in the Jerez paddock with a hospitality building, ready to join its new F1 rivals for the third winter test next week. Its car remains in the UK, where AUTOSPORT exclusively captured its shakedown yesterday.

10:23 At present most drivers are sticking to short exploratory runs to assess track conditions, so are lapping between 1m29s and 1m33s, and then returning to the pits to wait for better weather.

10:25 nicohulkenberg finding the conditions frustrating: "Rain in Jerez is getting worse and worse..."

10:26 Hulkenberg remains the most active driver of the morning so far, having completed 37 laps in the opening two and a half hours. Webber and Rosberg are next up on 25 and 20 respectively.

10:37 At present Webber is lapping in the 1m30s/1m31s region while Button is in the 1m32s/1m33s, but with track conditions fluctuating and teams taking different approaches to their programmes in the wet, times are hard to judge.

10:45 Alonso has returned to the track. Ferrari decided to use the rain as an opportunity to do some work on the car that it had previously scheduled for lunchtime.

10:46 The Ferrari driver is using extreme wet tyres for this run.

10:50 virginracing's plans for the morning: "Burning midnight oil to get new parts on car & ready for off. Just started raining though, so early installation run then check weather."

10:50 Virgin looks set to head out for that installation run shortly.

10:55 Alonso is now back in the pits, leaving just Hulkenberg and Webber on the track. Both are lapping around 1m32s/1m33s as circuit conditions remain poor.

10:59 Button and Alonso set out again, while Webber ends his run.

11:00 After another hour of rain and damp track conditions, the times set in the brief period of early dry running still stand at the three hour mark: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s.

11:03 A view of the damp paddock from rf1paddock pass: "Rainy day..."

11:05 Despite the weather, Hulkenberg has become the first man to put 50 laps in the book this morning, and is now on his 53rd tour of the day. Webber is not far behind on 44 laps, while Petrov has completed only nine.

11:09 @virginracing: "We're all set! The VR-01 is about to mix it with the big guys out on track."

11:11 Alonso, Buemi and Liuzzi are the drivers out at present, with Alonso the quickest of the group and lapping in 1m32s.

11:12 Buemi now gets up to speed in the conditions with a 1m30.483s.

11:15 Rosberg heads back out, as Buemi and Alonso set times around 1m30s/1m31s.

11:16 Webber takes to the track again too.

11:20 The session has been stopped.

11:21 The first red flag of the week has been caused by Webber stopping in the new Red Bull RB6.

11:23 The recovery truck has been despatched to collect the Red Bull. Webber has climbed out of the car and had a good look at its rear end.

11:23 The Australian managed to complete 47 laps this morning prior to the problem.

11:37 Webber got back to the Red Bull garage shortly before his car was returned on a flatbed truck. Session should restart shortly.

11:38 The fans remain stoic, sheltering under umbrellas as the rain continues to fall and the track stays empty following Webber's problem.

11:49 eddstrawF1 brings news from Webber in the Red Bull garage: "It was just an oil leak. Not sure if it was engine or hydraulic. Nothing major."

11:50 @eddstrawF1: "Red Bull say it was a 'precautionary stop' because of the oil leak. Floor has to come off to clean up and make repairs."

11:51 Testing resumes after the stoppage, with Alonso and Button first to leave the pitlane.

11:52 Virgin fires up the VR-01 in its garage in preparation for the team's first laps alongside its competitors.

11:55 Alonso came straight back in after his out-lap, so Button continues with the track to himself.

11:57 Button pits as well, so the track is now empty.

12:03 Rosberg now rejoins, while Ferrari says it is taking "a quick lunchbreak".

12:07 Another hour passes without any change to the timing screens due to the rain, so the order at 1pm local time remains as follows: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s.

12:10 Timo Glock is being strapped into the Virgin VR-01, with the team hinting that it is about to hit the track.

12:11 The track is silent again with Rosberg having returned to the Mercedes garage.

12:12 Renault's Vitaly Petrov hasn't been out at all since the rain started just over three hours ago, but the team's rf1paddockpass promises activity soon: "And still the rain falls in Jerez…but there’s some action in the garage. Looks like we will be heading out soon. Maybe in half an hour or so."

12:16 Virgin hits the track for the first time with Glock at the wheel.

12:16 Update from Williams's technical chief Sam Michael via @clairevwilliams: "Sam reports that the car has run problem-free this morning. One run on dry tyres first thing, the rest on inters & wets."

12:18 With Glock handling Virgin's first public runs, his team-mate Lucas di Grassi is just a spectator today.

12:18 Glock returns to the pits after an oversteering installation lap in the Virgin-Cosworth VR-01.

12:24 Mercedes takes its turn for a lunchbreak. Liuzzi and Hulkenberg are the men on track now.

12:29 Having taken his tally for the day up to 60 laps, Hulkenberg pits. Liuzzi continues on.

12:34 Liuzzi now pits too. He has put 37 laps on Force India's new car today.

12:34 Track conditions have not improved, though. Liuzzi was lapping in the 1m33s on that last run.

12:48 Hulkenberg ends the lull by heading back out for Williams.

12:51 Buemi also resumes running. The Toro Rosso is still second in the order behind Rosberg, having got some quick laps in before the prolonged rain began.

12:53 Hulkenberg pits, having now completed 67 laps today, as Liuzzi comes out to join Buemi in action.

12:55 Light drizzle continues to fall on Jerez, keeping the track damp - with standing water still visible in places. The track temperature has risen very slighty from earlier and now sits at 14 degrees.

12:59 Five hours into today's test, and the times from the opening 45 minutes of dry running remain the best so far: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s.

13:04 Hulkenberg rejoins for yet more laps. Currently times remain in the 1m30s-1m32s region.

13:09 More details of Virgin's first run alongside its rivals:

Virgin becomes first new team to test

13:11 Having sat out all of the wet running so far, Petrov has got back on track for Renault. Alonso is also setting off on another run.

13:12 Rain prediction from insideferrari: "Maybe the weather could improve in around one hour"

13:14 Alonso and Petrov now have the track to themselves. The Ferrari's times are around 1m32s/1m33s, the Renault varying between 1m34s and 1m36s.

13:15 Hulkenberg heads out again for what will be his 71st lap of the day.

13:22 Hulkenberg has done a couple of out and in laps straight back to the Williams pit. Petrov's run has also come to an end, with Buemi joining Alonso on the circuit. The Ferrari reeled off a string of consistent low 1m32s laps, but is now circulating a second slower than that.

13:33 Kobayashi and Button head out, while Buemi and Alonso end their runs.

13:34 Liuzzi's first impressions of the Force India VJM03, courtesy of eddstrawF1: "In the dry the balance felt good, although when it started to rain it made it more difficult to judge how the car was. It's not ideal with the rain but we will do our best to get through everything."

13:39 Apart from Glock - whose activity has been limited to an installation lap so far - Petrov has the lowest mileage of any driver today. But he has recently rejoined from the Renault pit to complete his 20th lap of the session.

13:41 Petrov only does a few laps before returning to the pitlane. Kobayashi and Button now have the track to themselves and are both lapping in the 1m33s, although Kobayashi did a 1m31s earlier in his current stint.

13:46 While Kobayashi and Button end their runs, Buemi, Liuzzi and Hulkenberg set out from their respective garages for yet more wet track exploration.

13:49 But Buemi and Hulkenberg don't stay out long, so now Liuzzi has the track to himself once again, taking the new Force India round in 1m33s.

13:52 With so much running lost to rain today, the teams will be anxious to make amends tomorrow. Luckily for them, the current Thursday forecast looks more positive, with dry weather and a temperature of 15 degrees anticipated at present - although Friday is set to see more rain.

13:53 The weather forecast reports a slight chance of showers on Saturday too, so if conditions do remain good on Thursday, it could be the only chance for significant dry running all week.

13:54 Liuzzi picks up his pace and laps in the 1m32s, as Alonso and Button also head out again.

13:57 Alonso is quickly up to speed with a 1m30.313s - the best time anyone has achieved in a while, but still nearly 10s off the dry pace from first thing this morning.

13:58 The double world champion goes another 0.7s faster on his next lap.

14:00 Full list of times with two hours to go: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s.

14:00 All set prior to the rain starting just before 10am local time this morning. Glock has yet to complete a flying lap for Virgin.

14:02 Buemi and Button are currently on track with Alonso. The Ferrari's pace has dropped off to the 1m31s region, while the Toro Rosso and McLaren are lapping in 1m34s/1m35s.

14:06 Alonso has ended his run and pitted. Buemi continues to lap around 1m34s in what remains steady rainfall, while Button's times have come down to 1m32s.

14:07 Hulkenberg, currently in the pits, is still the most active driver of the day with 79 laps completed. Buemi has now managed 62.

14:09 Latest Virgin news from eddstrawF1: "Virgin say that the car will be returning to the track for further installation laps shortly."

14:11 Plenty of pictures from today's action to be found on AUTOSPORT.com:

Jerez testing gallery

14:12 Hulkenberg has begun another run with a 1m31.135s lap. Buemi is also still out, while Button is back in the McLaren pit.

14:13 Most drivers have completed plenty of wet weather mileage today, but Rosberg and Petrov have only done relatively short runs since the start of the rain, and Webber has yet to rejoin following the oil leak that stopped the new Red Bull three hours ago.

14:14 @eddstrawF1: "I can't see us getting any more dry times today. Gloom as far as the eye can see... which isn't far!"

14:15 Buemi continues on a long run with times in the 1m33s/1m34s region, with Hulkenberg lapping in the 1m31s.

14:19 Conditions have never been appalling at any stage today, but the consistent drizzle and showers have kept the track damp enough for intermediate tyres at least. The light has also been poor, with a generally murky atmosphere around the circuit.

14:22 Hulkenberg pits after a consistent string of 1m31s laps. Buemi is still pounding round the track and is now joined by Liuzzi again.

14:24 Force India pleased with its progress so far despite the weather, @clubforce: "Lap timings improved a bit in the wet (vs before). Slightly better than Buemi and Kobayashi in the Toro Rosso and Sauber respectively."

14:27 Alonso and Button come back out, and once again the Ferrari is quick from the outset, starting with a 1m30.259s lap.

14:28 Buemi completes his long run and returns to the Toro Rosso pit.

14:33 Glock brings the Virgin back out for its second appearance of the day

14:34 After three laps in the 1m30s, Alonso drops back into the 1m31s. Button is moving in the opposite direction - his run starting with a string of 1m32s, but the world champion now consistently in the mid-1m30s. Liuzzi has pitted after a run of 1m32s laps.

14:35 Just another installation lap for Virgin Racing, Glock coming straight back into the pits.

14:37 Button ends his run and pits, as Hulkenberg sets out to add to his 88 laps.

14:39 Straight up to speed for Hulkenberg - a 1m29.907s on his second flying lap.

14:42 Hulkenberg keeps improving, producing a 1m29.6s and then a 1m28.606s - the best lap for several hours.

14:44 Current pacesetter Rosberg heads out. The German has done little running in the wet and is only on his 30th lap of the day, where Hulkenberg is on lap 94.

14:44 eddstrawF1 with information from Renault on Petrov's quiet day: No problems with the car, just keen not to waste mileage in the wet.

14:45 The Russian rookie has only done 23 laps so far.

14:46 Hulkenberg did four laps and then pitted. Alonso is still on a long run - completing a 12-lap stint so far and lapping in 1m30s/1m31s throughout.

14:47 Alonso picks up his pace on the 13th lap of this run, suddenly throwing in a 1m29.1s. Hulkenberg has come straight back out to join him and Rosberg.

14:50 Alonso heads for the pits.

14:53 Rosberg's pace is in the 1m33s on this run so far, while Hulkenberg is circulating in 1m30s.

14:54 Glock pulls out on track again, with Button also leaving the pitlane.

14:55 Hulkenberg completes another four-lap run and returns to the Williams garage.

14:56 Glock has stayed out - will this be Virgin Racing's first flying lap at a group test?

14:57 Glock sets a 1m38.734s first time around.

14:58 Bear in mind that the rest of the field all managed at least half a dozen laps on a dry track first thing this morning. The Virgin heads back to the pits, while Buemi has joined Button on the circuit, Rosberg having ended his run.

15:00 Heading into the last hour, the top nine times remain unchanged since the start of the rain: 1 Rosberg 1m20.927s; 2 Buemi 1m21.031s; 3 Hulkenberg 1m22.243s; 4 Alonso 1m22.895s; 5 Kobayashi 1m23.787s; 6 Button 1m24.947s; 7 Liuzzi 1m24.968s; 8 Petrov 1m25.440s; 9 Webber 1m26.502s; 10 Glock 1m38.734s.

15:01 Button came in without trying a flying lap that time, so Buemi is now the sole driver in action.

15:07 As Buemi finishes his run, Alonso, Liuzzi, Kobayashi and Hulkenberg all head back out.

15:15 If anything the conditions appear to be getting slightly worse now. The spray behind the cars is increasing, and Hulkenberg and Alonso have taken longer to get up to speed this time. Kobayashi pitted after just one lap.

15:23 Red Bull continues to work on Webber's car in the hope that the RB6 will run again in the remaining 40 minutes of the session.

The car hasn't been out since stopping with an oil leak four hours ago.

15:25 Alonso gets down to 1m28.7s before returning to the pits. Rosberg, Kobayashi and Hulkenberg are currently on the circuit, with the latter now on lap 112 for the day.

15:32 Going into the final half hour of this damp Jerez day, Liuzzi is now the only man on track and the rain is falling quite heavily.

15:35 Petrov heads out again for only his second run since the rain started. He has only completed 23 laps so far today, with Renault preferring to wait for better conditions.

15:38 Liuzzi pits as Rosberg sets off for another run.

15:41 Just a handful of laps for Petrov again and he returns to the Renault pits, leaving Rosberg with the circuit to himself.

15:44 Webber has rejoined after Red Bull completed repairs following the earlier oil leak.

15:45 Alonso has also commenced another run, and should finish the day with around 90 laps under his belt.

15:47 Alonso does another 1m28s lap and then heads straight back to the pits. Rosberg is reeling off 1m33s/1m34s laps on a longer run, while Hulkenberg has also come back out.

15:48 Webber returns to the Red Bull pits.

15:52 The session has been stopped.

15:53 It seems that Rosberg could have caused the stoppage.

15:54 The German's Mercedes has come to a halt on the far side of the circuit.

15:54 With just five minutes to go, this could bring the day's running to an end.

15:56 It looks like the Mercedes has stopped due to a mechanical problem rather than an incident.

15:57 With light fading rapidly, it's hard to see this session resuming.

15:59 The marshals are still working on retrieving Rosberg's car.

16:01 The chequered flag is shown.

16:01 So the first day of the second winter test is over, with all the quick times set in the first 50 minutes before the rain set in, and Rosberg ending the day on top of the timesheets but parked at the side of the road.

See the box on the right for the final times for the day.

16:02 Despite the weather, several teams still got some valuable wet weather mileage - with Hulkenberg notching up a session-high 118 laps.

16:02 Thanks for following the action live with AUTOSPORT - keep checking the website for news and reaction this evening, and join us again for continuing live coverage of day two at Jerez tomorrow morning.