07:52 Huddled fans, frosted windscreens and the intermittent scream of a V8 - it's a cold start to the second day of F1 pre-season testing at Barcelona. Welcome back.

07:55 And it's (thankfully) not just the AUTOSPORT Live team being delicate, at least not according to some team Twitter feeds:

@Marussia_F1Team: "A v Good Morning from a V cold Circuit de Catalunya. Ice on the windscreen means cold out on track - need some F1 cars to blaze a trail."

@OfficialSF1Team: "Today @NicoHulkenberg will be at the wheel of the C32, continuing the programme that @EstebanGtz started yesterday. It's pretty cold!!"

@Lotus_F1Team: "Good Morning from Barcelona. Another chilly morning, but a clearer sky than yesterday."

08:00 We have a few changes in the driver line-ups today. Lewis Hamilton comes in for Nico Rosberg at Mercedes, Nico Hulkenberg replaces Esteban Gutierrez at Sauber and Valtteri Bottas swaps with Pastor Maldonado at Williams.

08:01 We're green and we're already underway - Charles Pic and Max Chilton were out almost the second the pitlane opened.

08:01 And Bottas now joins the pair. The Finn is getting his first taste of the FW35 today.

08:07 AUTOSPORT will be speaking to Bottas at the end of the day to hear his feedback on Williams's new car.

Yesterday Pastor Maldonado said progress with the new car was clear to see. You can read his views here.

08:08 @Marussia_F1Team: "Our plan for this (cold) morning is aero evaluation & set-up work. Times won't be a factor, data will."

08:09 Despite the cold, Vettel is the only man yet to go out this morning. Plenty of exploratory laps but no times set as of yet.

08:10 @InsideFerrari: "Goodmorning to all! @alo_oficial just completed an installation lap. The programme for the day will kick-off shortly."

08:12 Scratch that, Vettel heads out in the RB9 and all 11 teams have now been out for at least one installation lap.

08:21 If you missed it last night, there was plenty of other interesting reaction from the Barcelona paddock.

Fernando Alonso believes the F138 is capable of challenging for the 2013 world championship - which might sound a bit premature but for his pretty undeniable logic that if he almost won with last year's car, he stands an even better chance in the forthcoming campaign.

08:24 Sebastian Vettel meanwhile insisted Red Bull is not wasting any time worrying about the progress of rival teams, particularly because it has "plenty of stuff going on" in its own garage.

08:26 And if you've ever wondered what a Vettel post-session media scrum looks like, here's a snap. Sam Tremayne somehow got himself to the front (or at least within listening distance).

08:27 Installation laps are still the order of the day so far at Barcelona. Bottas, five laps to the good, has been the busiest driver of the morning.

08:28 Lewis Hamilton, in for Nico Rosberg today, sets the first time laps of the morning. He follows up a 1m31s effort with a 1m28.723s.

08:28 Bottas and Ricciardo have also set flyers now, although that's not really the most accurate description given times are around 10s slower than yesterday.

08:31 Hamilton improves by over a second and is well clear at the front. Vettel meanwhile is keeping the Red Bull boys busy as he twice comes in for practice pitstops.

08:33 Improvements for Pic, Ricciardo and Bottas now.

08:37 And Hamilton improves again on his fifth flying lap - he's dipped down to a 1m27.563s on the medium tyre.

Temperatures have confused the picture slightly, but nearly every driver down the pitlane reported extremely high degradation yesterday. Rosberg, Vettel and Alonso were among those surprised by just how quickly the new compounds dropped off. Read it here.

08:41 @WilliamsF1Team: "Another front wing for #BOTTAS - it's all about gathering data this morning - not pushing for times.

"Valtteri back in for further changes - old tyres and cold track not the easiest first run! But we've got some good data already"

08:44 Sergio Perez takes over from Lewis Hamilton at the top of the timesheets.

08:46 A string of improvements for Max Chilton, who goes faster for three successive laps. His current best is a 1m32.681s.

08:52 @clubforce: "Last checks on the VJM06 before @pauldirestaf1 starts the morning programme - first item on the menu is aero work."

08:53 Plenty of flow-vis on Hamilton's Mercedes and Ricciardo's Toro Rosso this morning.

08:53 And plenty of work for the Red Bull garage just below our station in the media centre. Vettel has already completed four practice pitstops this morning.

09:03 Ever wondered what tyres drivers were on for their fastest laps? AUTOSPORT Live (with a helping hand from Pirelli) have been keeping tabs on the situation - check out our table at the bottom of yesterday's report.

09:07 Yesterday Edd Straw was kept busy with the latest rumblings over Williams's exhaust layout.

Williams was sure it's design was legal. Perhaps not, said the FIA.

09:09 And on the FW35 front, our technical expert Craig Scarborough picked through the key details of Williams's 2013 challenger for AUTOSPORT. Subscribers can read his definitive analysis below.

Under the skin of the Williams FW35

09:11 Just over one hour into the second morning, we're still yet to see flying laps from Vettel, Hulkenberg, di Resta or Raikkonen.

09:12 Valtteri Bottas currently leads the way on the lap count, racking up 20 (and climbing). Lewis Hamilton and Charles Pic are next up with 15.

09:14 Fernando Alonso and Paul di Resta are both yet to reach double figures, but the man bringing up the bottom is Kimi Raikkonen on just four. To the Finn's frustration, a data issue also restricted his mileage yesterday.

09:17 Hamilton sends Mercedes back to the top of the timesheets with a 1m24.559s.

09:18 Sebastian Vettel meanwhile sets his first flying lap of the day, some three seconds off Hamilton's benchmark.

09:25 Have a question about testing? Curious to know which drivers or teams are genuinely upbeat rather than cautiously optimistic (or even worried)? Or why some teams run pitstops drills and others coat their cars in flow-vis?

We're opening up AUTOSPORT Live to all your questions this morning, with our F1 Editor Edd Straw poised and ready. Get sending to live@autosport.com.

09:34 In the meantime, you can read Edd Straw's day one blog from Barcelona - or why F1's phoney war really ramps up at the Catalan track.

09:35 Sebastian Vettel shaves a few tenths off his previous best. The RB9 is our only car out on track at the moment.

09:35 And of course, just as we write that he comes in. After 90 minutes of busy action, we have a moment of rest.

09:37 Which is a good time to run through the lap count so far today:

Hamilton 23
Perez 15
Bottas 26
Pic 15
Vettel 18
Chilton 16
Ricciardo 16
Alonso 11
Hulkenberg 15
di Resta 13
Raikkonen 4

09:38 Hulkenberg, di Resta and Raikkonen incidentally are all still yet to set a time.

09:42 Valtteri Bottas making use of a clear track as he lowers his own best to a 1m25.773s.

09:44 @OfficialSF1Team: "So far @NicoHulkenberg has been doing aero evaluation work, therefore no laptime yet."

09:46 Ricciardo, on the hard compound, jumps from seventh to second with a 1m25.354s.

09:50 Talking of Hulkenberg, here's a photo of him from early this morning, still wearing a coat while putting his helmet on. We're not sure why we like it so much...perhaps just because it reminds us of our own formative karting days.

09:51 We have a new leader - on his first flying lap of a new stint, Vettel lowers the benchmark to a 1m23.653s.

09:52 Alonso also finds a chunk of time (around eight seconds) to vault into second.

09:52 Both he and Vettel are on mediums, incidentally.

09:53 Short runs over for Vettel and Alonso and they're both back into the pits. Hamilton and Pic are our two men on track.

09:56 @InsideFerrari: "Let's practice some starts, but first..."lay rubber" on the pit-stop area...!"

09:57 Vettel's spell at the top didn't last too long, as Hamilton moves back ahead with a 1m23.274s.

09:58 That time, set on hards, included new overall bests in all three sectors.

09:59 It's also just over two tenths of a second slower than Vettel went on the opening morning, which suggests the track is starting to rubber up nicely.

10:02 Our first question for Edd Straw comes from Oliver Heycoop, who asks:

Do you think it was an advantage or disadvantage for Williams to debut the FW35 later, and in doing so having more time to develop it?

Edd Straw: "As a rule of thumb, sacrificing one-third of your pre-season running when it is at such a high premium is not a good thing. But as Williams technical director Mike Coughlan pointed out yesterday the decision hinged on the value of Jerez as a test venue.

"Coughlan claims that the car would definitely have been ready for the first test had it been at Barcelona and that the car has run reliably following exhaustive dyno work back at base.

"The fact that it was the only team to take this path suggests one of two things; either Williams was wrong to do it or Coughlan has made a bold decision that could look very wrong if the team struggles in 2013. Based on its current start, it doesn't appear to be a major handicap."

10:07 Aside from telling Edd Straw about omelettes, Jaime Alguersuari admits he is unlikely to race outside Formula 1 this season after failing to secure a return to the grand prix grid. Read the full story here.

10:13 Sergio Perez paints the timesheets green - personal bests in all three sectors take him to fourth and a 1m25.755s.

10:15 Perez follows that up with two laps in the 1m25s.

10:16 Vettel can better that though - in fact he can better Hamilton too. Outright bests in all three sectors send him three tenths clear at the top.

10:18 Run complete, Perez heads into the pits.

10:18 Vettel, on mediums, backs off massively on his second flyer and then comes round in a 1m23.910s - still faster than anyone but Hamilton even if it nine tenths off his best.

10:21 Some news from the Lotus camp, where Raikkonen has managed just four laps so far this morning:

@Lotus_F1Team: "We can officially deny any rumours that we're having an exceptionally long breakfast; we're changing gearbox. Running will be resumed soon."

10:28 Kevin from Belgium is next up in our "Ask Edd" section. It's a two-parter, so we've split it accordingly.

Year after year we see designs appearing during the pre-season tests which are subject to discussion. This year again with the Caterham and Williams vanes to conduct exhaust flows. Why are teams allowed to run "illegal" car designs during testing? Is this only to allow testing gear to be fitted to the car?

Edd Straw: "Only the safety regulations apply during testing. As of last year, teams had to pass all of the mandatory crash tests before running. To regulate testing is unnecessary because it is private practice, so it's for the same reasons as football teams don't have official referees supervising training.

"On a practical basis, bringing all of the testing and measuring equipment, not to mention scrutineers, would be costly. Also, you can be sure that teams would constantly try throwing dubious parts at the cars as test cases given that there would be no real consequences to failing scrutineering.

"If Williams and Caterham run the parts in Melbourne, they run the risk of exclusion. The FIA's representatives, such as Charlie Whiting, are able to offer informal advice to the teams about certain things on the cars, either off their own bat or when asked, however."

10:28 As we hear from Edd, Bottas has just set a new personal best in the FW35 - a 1m24.458s sends him fourth.

10:37 And a second from Kevin:

Why does the FIA (and stewards) wait until the first race to formulate a definite answer on the legality of designs? Wouldn't it be more clear and less open for discussion to issue official warnings to teams before the first race?

Edd Straw: "The FIA has told Williams and Caterham what it thinks - that the vanes are illegal. That is as good as a promise that if they were on the cars in Australia, they would report the matter for the stewards for deliberation.

"At this point, the teams would be able to make their own case, and it would be down to the stewards to make the final decision. Remember, last year the Red Bull was declared illegal by technical delegate Jo Bauer after qualifying at Hockenheim, but the stewards rejected this (albeit with some reservations). But don't make the mistake of thinking that the stewards and the technical team are necessarily of one mind or interchangeable. In this case, the technical team are the police and the stewards the judges - which fundamentally is a sensible system.

"Resolving these problems outside of race weekends does happen, usually behind closed doors, but it is not possible to make an official ruling based on test trim as cars are allowed to run underweight, covered in sensors or even with parts that might not be legal until next year."

10:38 Vettel vaults more than a second clear of the field after outright bests in all three sectors.

10:39 He improves again in the first sector of his next effort, but is slightly slower across the rest of the lap. His 1m22.708s is still faster than anyone else has been so far today.

10:41 Alonso and Hamilton head out for Ferrari and Mercedes respectively.

10:43 Vettel yesterday insisted that Red Bull had "plenty of stuff going on" in its own garage following the first day of testing at Barcelona. The RB9 is currently looking good out front.

10:44 Green on the timesheets for both Alonso and Hamilton.

10:45 The Ferrari man improves to a 1m23.247s on the medium compound, but stays third.

10:45 Hamilton, on hards, then comes round in a 1m22.882s, closing to within seven tenths of Vettel.

10:51 Alonso pits just as Vettel heads back out. We have the the day's two fastest men on track, joined by fourth-place man Valtteri Bottas.

10:55 Vettel, on hards, heads back in after a very brief run in the 1m23s. Hamilton still out, as are Bottas, di Resta and Hulkenberg.

10:56 Hulkenberg incidentally is yet to set a time. Raikkonen is also in that boat following his morning gearbox change.

10:59 Hulkenberg's first flyer of the day is a 1m26.146s, enough to send him into eighth.

11:00 That time was set on mediums incidentally. On the hards, Vettel comes round in a 1m22.922s.

11:02 Some teams alternate the drivers over the four test days test, whereas others give each driver two days in a row. It seems to me that giving a driver two full days is better than the on again off again approach. What is your opinion? Rick

Edd Straw: "It depends what the team's programme is and probably makes little difference overall.

"Giving a driver back-to-back days perhaps helps with momentum, but the day-on, day-off strategy allows a driver to spend a day in between following progress from the outside. There's probably no better or worse way to do it provided you give equal time and don't always condemn the same driver to doing the first day when the track is at its worst."

11:08 How many races do you think Hamilton will win this coming season, if any? @jimbobwinny

Edd Straw: "It's going to be a difficult year. He's got the ability to make the most of an opportunity if one presents himself, but his own prediction of not winning a race this year could prove accurate.

"A reasonable forecast right now would probably be either no wins or one win, but let's see how the Mercedes looks as testing advances and more parts are added to the car."

11:13 Vettel again goes faster than anyone else has managed with a lap in the low 1m22s. Hamilton and Alonso remain the only men within one second of the reigning champion.

11:13 He's racking up the lap count too - he's now on 40 for the day and is about to up that further after heading out. Charles Pic is the only other man out on track.

11:16 Vettel edges further clear with a 1m22.197s.

11:17 Vettel's main gains then came in the middle sector, where he set a new outright best. It was a soft tyre run, and after one effort he heads back in.

11:19 Bottas, also on softs, improves his own time but stays fifth. A 1m23.561s now for the Finn.

11:21 Sergio Perez vaults from seventh to second. His own soft tyre run produces a 1m22.743s, which moves him to within six tenths of Vettel.

11:23 That didn't last long. Hamilton, still running on hards, reclaims second with a 1m22.726s.

11:24 Hamilton's lap included a new outright best in sector three. Despite topping the sector one speed trap, he surrendered around three tenths to Vettel in the opening split.

11:29 Hamilton is still out and has found a bit of consistency in the 1m26s bracket. Chilton the only other man on track.

11:33 @WilliamsF1Team: "53 laps and we've completed our aero programme so that's it for our morning running as we are stopping for the lunch break. The boys are now straight into prep work for the afternoon session where we'll be doing tyre runs and set-up work with #BOTTAS. His first impression is that we've got a good car. He's happy!"

(We'll be finding out his full reaction this evening).

11:34 Hamilton is still out on his hard tyre run. His pace has tailed off, but only slightly - he's now circulating in the 1m27s.

11:39 On the Banner Watch front, Pedro de la Rosa and Robert Kubica fans are still out in force. The Pole won't be joining DTM, it was confirmed earlier today, after Mercedes announced a six-car line-up.

11:42 Di Resta has improved his time to a 1m24.007s.

11:42 His former team-mate Hulkenberg then does the same in the Sauber, clocking a 1m24.797s.

11:43 RIcciardo also improves, lapping in 1m23.718s in the Toro Rosso.

11:44 Hamilton is now back out on track again in the Mercedes.

11:44 Di Resta, Ricciardo and Hulkenberg had all been lapping at a similar mid-1m24s pace. The Force India now pits.

11:45 Another slight improvement from Hulkenberg as he does a 1m24.636s.

11:45 No flying laps from Hamilton that time. He returns to the pits.

11:46 Then the Mercedes heads straight back out again.

11:51 Adrian Sutil is already at Barcelona preparing for his F1 testing comeback with Force India tomorrow.

11:54 "If we allowed all the technology available to F1 (ground effect, double diffusers, blown diffusers, flexible skirts etc) would we now, in Edd's opinion, be in a position where a human being could not withstand the forces of driving it on the limit? Any guesses at a time round Barcelona qually for such a piece of kit?" asks James Limburn

Edd Straw: "The idea of an unrestricted formula is an enticing one. I'm going to hand you over to Adrian Newey to answer that!"

11:55 The lunchbreak at Barcelona is now only five minutes away, and already things are getting quieter on track with just di Resta and Chilton out there.

11:55 Ricciardo now joins them.

11:55 As does Pic.

11:56 Di Resta keeps trimming a few fractions off his time, now getting down to 1m23.971s.

11:58 It's looking like a repeat of yesterday's morning session at the top of the timesheets, with Vettel again going for lunch with a half-second margin over the field.

11:59 Hamilton and his McLaren replacement Perez are next up, followed by Alonso, Bottas, Ricciardo and di Resta.

12:00 There's the chequered flag to signal the end of the morning running.

12:01 Top lap count for the four-hour session belongs to Hamilton on 64. Bottas did 53, Pic 51, Ricciardo 46, Vettel 43, di Resta 41, Hulkenberg 39, Perez 35 and Alonso 28.

12:02 Only four laps and no times at all from Raikkonen. His big hope for Wednesday was more mileage after Tuesday's disruptive data issue, but a gearbox problem has kept Lotus in the garage for most of the morning.

12:03 AUTOSPORT Live is now taking a pause for a break that may or may not involve lunch. Back at 1pm GMT for the afternoon's action.

13:00 The green flag comes out, some engines hum and we're back underway for the afternoon at Barcelona.

13:01 Hulkenberg is first out in the Sauber.

13:02 Latest news from Lotus is that it could be some time before Raikkonen comes back out again.

13:02 The E21 requires a gearbox change and with only limited spares available it is taking time. The Finn only managed four shakedown laps this morning.

13:03 Perez sets off in the McLaren. He ended the morning in third place.

13:04 Thanks for all your questions to AUTSPORT F1 editor Edd Straw this morning. He's now heading trackside for the afternoon but might be able to slip a few more answers in.

13:05 Current pacesetter Vettel is also on track again.

13:09 Perez is running hard tyres on the McLaren. He started off with a 1m23.2s laps, then a 1m23.4s and now a 1m25.4s.

13:09 Bottas is keeping the McLaren company. The other cars have come in.

13:10 Perez also now pits.

13:10 Bottas is lapping consistently in mid-1m25s on a set of hard Pirellis.

13:11 The temperature info screen isn't available in the press room right now, but the day is warming up and might make tyre data more reliable. It was hovering around 3 degrees when the test began this morning.

13:12 Bottas comes round in 1m26.6s on his next lap.

13:14 Bottas brings the Williams back in, but not before Pic took the Caterham out.

13:16 Pic's first flying lap is his best of the day, with a 0.7s improvement to 1m26.243s.

13:17 The Caterham backs off by five seconds on the next lap.

13:18 Hulkenberg brings the Sauber out.

13:18 That will please the owner of the German flag that has appeared in the grandstand today.

13:19 Hamilton re-emerges in the Mercedes, and the noise below our feet suggests Vettel will soon hit the track in the Red Bull too.

13:23 Vettel came out for just a shakedown lap, then returned behind the secrecy screens.

13:24 Hamilton, Perez, Hulkenberg and Chilton are now out.

13:27 Perez improves to second fastest on a 1m22.586s in the McLaren.

13:30 Vettel, di Resta, Pic and Hulkenberg all head out in quick succession.

13:34 @Lotus_F1Team: "New gearbox and rear assembly nearly on, could be back out for last couple of hours if everything goes to plan."

13:37 Sergio Perez launches himself to the top of the timesheets with a 1m21.818s.

13:38 That lap, set on softs, included outright bests in the first and final sectors.

13:39 And after going clear, Perez comes into the pits next time round. For reference, the fastest time on softs during last year's test(s) at Barcelona was a 1m22,312s.

13:40 Vettel and Hamilton have just headed out, while di Resta is also out on track.

13:44 More pit stop practice for Red Bull. Vettel exchanges softs for softs and is back on his way.

13:45 @clubforce: "First run of the afternoon session for @pauldirestaf1 - it's going to be a longer one on hard tyres."

13:48 An RB9 tearing down the main straight gives Chilton the perfect excuse for a practice start on the pitlane exit. It's all very smooth and he joins Vettel, Hamilton, Alonso, Bottas, Ricciardo and Hulkenberg on circuit.

13:51 Vettel crosses the line in 1m30.780s on the third lap of this stint.

13:53 A second slower that time for Vettel as he laps in 1m31.857s.

14:06 AUTOSPORT Live returns to life after a brief internet disconnection. Vettel is now out on hard tyres and lapping in mid-1m31s.

14:06 Alonso, also on hards, is doing mid 1m25s.

14:07 The Finnish fans opposite the Lotus pit are about to smile as the team tweets that Raikkonen's car will finally reappear soon:

14:07 Lotus (@Lotus_F1Team): "Box bolted on, engine fired up and making lots of noise. Checking sensors, temps etc"

14:14 Vettel pits, does a racing-style pitstop onto another set of hard tyres, then switches the engine off and is wheeled back in with cooling fans on the brakes.

14:18 Hamilton is out on medium tyres for Mercedes, and his initial 1m25s laps have now gone up to mid 1m27s.

14:19 Alonso continues on hards in 1m28s.

14:19 Raikkonen rejoins. He has yet to set a time today due to requiring a gearbox change.

14:19 Alonso now comes into the pits.

14:20 And straight back out again.

14:21 Current pacesetter Perez brings the McLaren back out.

14:21 Raikkonen returns to the pits for standard checks after that first lap.

14:27 Hamilton is still going on the same set of mediums, now lapping in 1m29.3s.

14:30 Raikkonen does his first flying lap of the day and goes straight to third on a 1m22.697s, using medium tyres.

14:32 Raikkonen quickly catches and passes Hamilton on the pits straight.

14:32 Chilton sets off for Marussia.

14:32 Alonso leaves the Ferrari pit and rejoins.

14:34 Hamilton pits to end that run for Mercedes.

14:35 Perez also comes in, leaving Raikkonen, Alonso and Chilton on track.

14:35 Raikkonen's times went up from that initial 1m22s to 1m24s, then a mid-1m25s and now a low 1m26s.

14:36 Chilton makes a quick pitstop and rejoins.

14:38 Alonso is lapping consistently in 1m24s on hard tyres, before going up to a high 1m25s on his fourth lap. He's using hard tyres.

14:41 Perez goes for another run in the McLaren.

14:43 The Mexican is using hard tyres for this outing and is now starting his first flying lap.

14:43 Loud engine revving from Red Bull downstairs but no sign of Vettel coming back out yet. Christian Horner strides purposefully into the garage.

14:44 Perez's first time is a 1m29.7s.

14:44 Alonso's laps are now in the mid-1m28s bracket.

14:46 Out at trackside, Sam Tremayne reports that on their last runs Chilton went around the outside of Hulkenberg at Turn 3, in a move that looked good even at a slow pace.

14:47 Perez's times go up by a tenth on each lap. Alonso is edging slightly closer to him and lapping a second and a bit faster.

14:47 Raikkonen rejoins as he and Lotus try to make up for lost time.

14:50 Alonso's rear rain light appears to be dropping off the Ferrari, reports our trackside team.

14:50 Straight on the pace again for Raikkonen as he kicks off with a 1m23.158s.

14:51 Perez's times now drifting upwards, as he does a 1m31s after a 1m30s.

14:53 Alonso comes in, pauses in the Ferrari pitbox briefly before taking off in a spectacular roar of engine revs. He then stops and is pulled back in.

14:53 Running on medium tyres again, Raikkonen does a 1m23.8s on his second lap.

14:56 The top four now out on track as Hamilton sets off on an out-lap. Raikkonen is the quickest man in action, does high 1m24s.

14:59 Vettel has rejoined too and starts off with a 1m28.3s. Hamilton's first lap was a 1m25s.

14:59 Hamilton catches Perez on track and lines up a pass into the first corner.

15:00 The Mercedes safely made it past the McLaren.

15:01 And hopefully along the way it provided an opportunity for someone to take a picture that can illustrate any Perez-compared-to-Hamilton-at-McLaren piece we ever want to run.

15:04 Hamilton's Mercedes looks much more nimble than Perez's McLaren on this run, but looking at the length of their stint, that is much more to do with fuel load and the age of tyres than car quality.

15:08 Vettel comes back past on hard tyres, lapping in 1m29.6s.

15:08 A Red Bull crew member shows the champion 'L35' on the pit board then changes it to 'L36'.

15:08 This seems to be a race simulation of sorts for Vettel, but it has been punctuated by long spells in the garage.

15:11 Raikkonen is lapping in 1m28.1s on medium tyres Vettel in high 1m29s and low 1m30s on hards.

15:14 Red flag, and looks like it might be Vettel who has stopped.

15:15 The Red Bull had just made a race-style pitstop, but pulled to a halt just after the pit exit.

15:16 Three course cars, a truck, a smaller truck and people with Red Bull blankets are on the scene.

15:17 Infiniti's title sponsorship has promped some colour changes for Red Bull. But the secrecy blanket is still blue. The trucks are now purple, and the car is moderately purple.

15:19 The Red Bull is now on the back of the recovery truck.

15:21 Something just happened in the middle of the pitlane that made some fans cheer. We have no idea what.

15:21 The recovery truck does an impressive u-turn for a truck and heads back up the pits straight.

15:23 The green flag comes out as soon as the truck pulls up at Red Bull.

15:25 While the Red Bull is unloaded, Perez, Raikkonen, Alonso, Bottas, Ricciardo and Pic immediately take to the track.

15:30 Chilton improves to 1m25.486s, putting Marussia ahead of Caterham.

15:35 Quickest man on track is Hamilton, who just got within a tenth of his best time of Wednesday so far.

15:35 The Mercedes is running medium tyres, while Alonso is out on hards for Ferrari and lapping in 1m27s.

15:36 Perez comes through with a 1m28.8s on hards.

15:36 Just a quick run for Hamilton, who now brings the Mercedes back into the pits.

15:41 Another improvement for Chilton as he does a 1m25.115s.

15:46 Lots of engine noise from the Red Bull garage below.

15:46 Sounds like Vettel's car is already back to full health.

15:46 And sure enough, the world champion rejoins.

15:47 Just before that, Perez ran through the pitlane to do a practice start, slowing and warming the McLaren's tyres on the way down, then roaring away.

15:50 Heading into the final 10 minutes of the afternoon and we have everyone but Vettel, Bottas and Pic on track.

15:51 Alonso goes green in the first two sectors but his lap unravels in the third and a 1m24.094s is comfortably slower than his today best.

15:54 Hamilton, the day's busiest driver, passes the 120-lap mark.

15:54 Pic is also in triple figures (102), with Perez just four laps off - he's on 96.

15:56 Red flag, and it's for Marussia - Max Chilton is stopped between Turns 12 and 13.

15:56 Just four minutes remaining on the clock, so that could well be day two finished.

15:59 The MR02 is already being loaded up and whisked off, but the delay is a good time for a (possibly final) recap of today's lap count:

Perez 97
Vettel 84
Raikkonen (43)
Hamilton (121)
Alonso (76)
Bottas (98)
Ricciardo (70)
Di Resta (62)
Hulkenberg (88)
Chilton (67)
Pic (102)

16:00 That is indeed it for today then. Sergio Perez puts McLaren on top ahead of Sebastian Vettel, Fernando Alonso and Lewis Hamilton - one second covering the quartet.

16:01 We're off to hear from the teams and drivers in the paddock, so stick with AUTOSPORT for all the reaction later this evening.

16:01 We'll also have our first Trackside View from Barcelona, and the latest technical analysis from Craig Scarborough.

16:02 Join us for Live coverage of the third and penultimate day from 08.00 GMT tomorrow.