07:58 Good morning and welcome to AUTOSPORT Live's coverage of day two of the team pre-season Formula 1 test at Barcelona's Catalunya circuit.

08:02 Today's big novelty is the first appearance of Vitaly Petrov in the Caterham, and he is already out.

08:03 Charles Pic in the Marussia, Nico Hulkenberg's Force India, Sebastian Vettel's Red Bull, Nico Rosberg's Mercedes and Daniel Ricciardo's Toro Rosso also set off for the installation laps.

08:03 They are now all slowly dribbling back to the pits.

08:04 Dry and sunny today, with a top temperature of 13 degrees later.

08:04 Right now it's just 2.4 degrees.

08:05 But that's better than this time yesterday by about... 2.4 degrees.

08:05 No wind to speak of and track temperature a moderate 10 degrees. Again, about 10 degrees better than this time yesterday.

08:06 Rosberg comes back in after a second installation lap, as does Fernando Alonso in the Ferrari.

08:06 Sergio Perez has been out to shake the cobwebs off the Sauber too.

08:06 We've also just seen Valtteri Bottas have his first outing in the new Williams.

08:07 But one car we won't see today is the Lotus after yesterday's 'chassis issue' drama.

Lotus pulls out of test because of chassis fault

08:07 Lewis Hamilton now out too in the McLaren.

08:08 AUTOSPORT's F1 editor @eddstrawF1 analysed the Lotus situation in his blog from day one of the test for AUTOSPORT Plus subscribers:

Inside testing: Barcelona daily blog

08:09 And we also got our technical expert Gary Anderson to investigate the situation:

Analysis: What's wrong with the Lotus

08:11 All the cars are now back in, so we're going to see what sort of crowd is around.

08:11 Not much, but they've left their banners behind at least.

08:12 Including the slightly terrifying Jaime Alguersuari lamentation.

08:12 Pic goes back out. He is using the 2011 Virgin to gain experience this week before the 2012 Marussia appears next week, and completed more laps than anyone else yesterday.

08:14 Just another installation lap for Pic, who is now back in.

08:15 Apart from the Alguersuari banner, we reckon the most exciting things about today are Petrov in a Caterham, Bottas in a Williams, and Lotus going home.

08:16 When we say 'exciting', we mean of course 'newsworthy'.

08:17 Hulkenberg brings the Force India back out.

08:17 Jarno Trulli's abrupt - if not unexpected - departure from Caterham in Petrov's favour was the biggest story of the gap between tests.

08:18 So as the Russian takes his first laps in the Caterham, AUTOSPORT Plus subscribers can read @eddstrawF1's analysis of the deal and Petrov's prospect:

Caterham's Russian roulette

08:19 And also for AUTOSPORT Plus subscribers, Tony Dodgins explains why he believes Trulli could have got so much more from his 15-year F1 career:

Jarno Trulli: A talent unrealised

08:20 And in our News section, we learn that Trulli spurned an offer from Ferrari while racing for Toyota.

Trulli says he was offered Ferrari seat

08:21 While we were giving you plenty of reading material, Hulkenberg was kicking the day's flying laps off with a 1m31s then a 1m29.362s.

08:22 Perez now knocks the Force India off the top with a 1m25.288s for Sauber.

08:23 Already that's only a second off Sauber's best time from yesterday, when it had a couple of time-consuming minor issues.

08:23 Vettel and Ricciardo are out again as well.

08:24 Ricciardo kicks off with a 1m35.156s.

08:24 If you need a reminder of all yesterday's events, here you go:

Vettel fastest on day one at Barcelona

08:25 Most of the line-up is the same as yesterday, except for Petrov coming in at Caterham, Rosberg taking the new Mercedes over from Schumacher, and Bottas getting a Williams run.

08:25 Vettel pits, but only very briefly and he's back out.

08:26 Perez now gets down to 1m24.747s up front.

08:27 As Ricciardo improves to 1m30.177s, then 1m28.513s.

08:27 That second lap puts him up to second.

08:27 Perez still quickest by 3.7s though and only just over half a second off his Tuesday time.

08:28 Vettel, Bottas and Hamilton on track too, as well as our current top three in the times.

08:28 Perez's pattern seems to be one quick lap, one slow lap - this time around he clocks a 1m32.439s.

08:29 All 10 cars present have done at least an installation lap now. You won't see Lotus today after its dramatic problems yesterday, and HRT's issues with passing its crash test meant it didn't make it to this test as it had originally hoped.

08:29 Red flag.

08:30 Perez had just pitted, while Ricciardo just improved to 1m28.122s.

08:30 Bottas and Vettel had just set their first times of the day in 1m32.976s and 1m37.366s respectively.

08:30 Only Ricciardo and Bottas not back in the pits.

08:31 Bottas returns to the pits (not emulating his Force India counterpart Jules Bianchi's shunt last week) so it's Ricciardo who has caused this stoppage.

08:31 Red Bull takes the opportunity to do a practice pitstop with Vettel.

08:32 We're playing a guessing game in the media centre trying to work out where the Toro Rosso is.

08:33 It's at Turn 6.

08:33 None of us had our money on that.

08:33 Ricciardo caused a red flag yesterday as well, with what the team enigmatically described as "a technical problem."

08:34 The low loader is already out, and there is a swarm of mechanics on hand, impressing AUTOSPORT's Sam Tremayne, who felt it was all a bit tardy compared to Jerez yesterday.

08:34 Four track vehicles are at the scene too.

08:36 We can just see that the covers are now on the Toro Rosso.

08:36 It's hard to make out what's happening from this vantage point.

08:37 But, handily, as Ricciardo stopped yesterday too, we can help our imaginations with pictures of what a Toro Rosso on a lorry looked like on Tuesday.

08:38 Low loader moving now. And hopefully a line like that feels more tangible thanks to the picture below.

08:38 The truck exits the track on the outside of Turn 7 and we should be back underway shortly.

08:39 Back to green.

08:40 Sebastien Buemi, by the way, is an interested member of the Red Bull pit wall crowd today.

08:40 We're going to look at his face every time Ricciardo's Toro Rosso comes past.

08:41 And maybe he can hook up with the Alguersuari fans in the grandstand later.

08:41 Bottas, Alonso and Hamilton are first to go back out.

08:42 Followed by Vettel.

08:42 So we have Red Bull, McLaren and Ferrari out at the same time. Yes, we are trying to stoke up some slightly tenuous 'it's like a pole battle' enthusiasm.

08:43 Alonso cruises past the pits, Ferrari clearly working on data gathering and set-up.

08:43 The team has tended to make a low-key start to the mornings of tests.

08:44 Vettel comes through the pits and rejoins.

08:45 Ferrari and Force India are both running periscope gauges on their rollhoops, and McLaren has a smaller version of the same.

08:46 Bit more pitstop practice for Vettel, who comes in and straight back out. The Red Bull hasn't done a proper flying lap so far and its best time is a 1m37.366s.

08:46 Alonso getting up to speed more with a 1m30.824s.

08:47 Hamilton and Bottas set personal bests of 1m29.346s and 1m30.778s respectively too.

08:47 Everyone on the medium compound tyres at the moment.

08:47 Hulkenberg improves to 1m26.585s, still 1.8s down on Perez.

08:47 Vettel and Alonso now pit.

08:49 Hamilton pits as Pic exits.

08:50 Rosberg comes out in the new Mercedes.

08:51 Bottas gets down to a 1m29.321s.

08:53 Pic starts off with a 1m39.783s as Bottas pits.

08:54 Petrov is now the only man who hasn't registered a time as Rosberg completes his first public flying laps in the new Mercedes.

08:55 Although Michael Schumacher was at the wheel for the official roll-out yesterday, both men had a play with the W03 in a shakedown and a private test.

08:56 Alonso rejoins the fray.

08:58 Petrov's first flying lap is a cautious 1m39.651s, as Pic improves to a 1m35.060s.

09:00 Hamilton lowers his own best, lapping the Catalan track in 1m27.937s.

09:00 Alonso lowers the benchmark with first a 1m24.706s, then a 1m24.698s.

09:01 Still more than half a second off yesterday's pace.

09:02 Hamilton is back in the pits

09:03 While Alonso improves yet again to stop the clock at 1m24.659s

09:03 And another improvement for the Spaniard, who posts a 1m24.644s on his ninth lap of the day

09:04 Alonso is running on Pirelli's medium tyres

09:05 A slow 1m33.800s for Alonso now

09:06 Vettel jumps up with a 1m25.208s, his best of the day but nearly two second off yesterday's pace

09:07 Perez heads back into the pits

09:07 That's more like it for Vettel - he lowers the morning benchmark with a 1m24.370s

09:08 Alonso seems to be doing constant speed runs, posting a 1m37.287s before returning to the pits

09:09 Six-lap run for the Spaniard, including four of those in the 1m24s

09:09 Vettel sets a new overall best in S2, but doesn't improve

09:10 Bottas is back on track in the Williams

09:10 As Pastor Maldonado indicates, the Finn is running today only: @Pastormaldo: Bottas is running in the car, he is continue with the FW34 tests only for today.

09:11 A 1m25.814s for Vettel on the 14th lap of the day

09:12 Another slow lap from Vettel: a 1m29.440s this time

09:12 It's just him and Bottas sharing the track right now

09:13 There isn't an awful lot of action on track, as Sam Tremayne leaves the desk to go hunt some breakfast

09:13 In somewhat more relevant news, Vettel heads back into the pits

09:14 Bottas the only man on track

09:15 Now joined by Hulkenberg in the Force India

09:16 Bottas it taking i easy, lapping in the 1m29s, still some five seconds off the pace set by Vettel

09:16 Petrov is yet to return to the track after his first four laps with Caterham earlier on

09:17 Sam Tremayne reports that croissants and jam are a great breakfast treat

09:18 There's still very sparse crowds in the grandstand today

09:19 1m28s for Hulkenberg, 1m30s for Bottas

09:20 Hulkenberg goes around a second quicker, as Bottas goes around a second slower

09:21 Bottas completes his 20th lap of the day in a 1m32s

09:21 @MyCaterhamF1: We're making a few alterations to settings in the cockpit to get Vitaly comfortable in his office. Will be back on track shortly

09:23 Vettel is back out

09:23 Ricciardo joins the action too, returning to the track after having caused the red flag earlier

09:24 That didn't last long. He's back in the pits

09:24 But the good news is that Hamilton is heading out

09:24 Rosberg too

09:24 And Ricciardo follows suit. Five cars on track now

09:26 @kamui_kobayashi: ドコモ20万超えて止まった！！笑 多分接続事業先間違ってたな！！

09:26 We are not really sure what that means, but we thought we'd let you know anyway

09:26 Vettel pops up with a 1m23.056s

09:26 That's the fastest we've seen in this test so far

09:27 Hamilton moves up to the second with a 1m24.455s

09:28 The Briton is still 1.3 seconds off Vettel's best, however

09:29 Hamilton, Rosberg, Hulkenberg and Ricciardo are sharing the circuit at the moment

09:30 Williams is doing a some sort of hospitality thing in the second half of the media centre. There's a fence separating the two sides. Not sure if we are invited

09:30 So maybe this is what he said earlier: @kamui_kobayashi: My Phone fee over 2000 euro unfortunately just my blackberry stop at moment. I think I miss connection provider and over the limit for month

09:31 Ricciardo pitted, and then returned to the track almost instantly

09:32 Hamilton posts a 1m36s

09:32 Hulkenberg pits and Rosberg is back out

09:33 Ricciardo in and out of the pits again

09:34 Hamilton improves to a 1m24.275s, still 1.2 second off Vettel

09:34 Hamilton matched Vettel in S1 there, but lost around 0.5s in S2 and S3

09:35 And now he pits

09:36 Hamilton has done 21 laps so far today

09:36 Ricciardo still hasn't managed a flyer since stopping out on track in the first hour - he's back into the pits once more

09:36 The good news is the pitlane is bathed in sunlight, and the temperature has crept up past 7 degrees

09:37 The bad news is Rosberg has pitted and we have silence on the circuit

09:37 @clubforce: 28 laps so far for @NicoHulkenberg in Barcelona on day 2 of the test. The programme includes more aero sweeps and balance work before lunch.

09:38 Another update for our Japanese followers

@kamui_kobayashi: 確実にTwitterピコピコで接続先間違ってたんだけど、それより腹たつのは親父に早く払いに行ってとお願いしたのに多分もう酔っ払って忘れとる。。。 ドコモショップ閉まっとるやん！！！

09:38 Pic heads out for Virgin - or at least in Virgin's car, before the team was rebranded Marussia

09:39 Just the nine laps so far today for the Frenchman; only Petrov across at Caterham has managed fewer

09:40 Pic is still the only man on track

09:40 But Perez and Bottas decide to put an end to that

09:42 Pic down to a 1m29.323s. That's some six second quicker than his previous best today

09:44 Dave has mailed us some trivia about Bottas: Fun fact about Bottas...in addition to racing on track, he honed his skills on the PC online racing game "Live For Speed" and is quite well known and followed still on the games forums... I guess he doesn't have so much time on it now as Williams' simulator is probably a bit better..

09:44 As we write that, the Finn improves to a 1m27.328s

09:45 The crowd is on its feet, and that can only mean one thing

09:45 You guessed it, Alonso heads out of the pits

09:46 Pic improves to a 1m28.872s as Vettel joins the action

09:47 Plenty of cars on track now

09:47 By plenty we mean six

09:48 Alonso delights his fans by moving up to second with a 1m23.640s

09:48 The Ferrari driver is now half a second off Vettel's best

09:49 And because we know you love pictures of cars on trucks, here's a shot of Ricciardo's Toro Rosso from earlier today

09:49 Hulkenberg has also set the best lap of the day to move up to third: a 1m24.075s

09:50 Alonso is back into the pits

09:51 Ricciardo, Bottas and Hulkenberg are on left on track

09:51 All drivers except Petrov are now on double digits. The Russian is still stuck on four laps

09:53 Alonso's time from today is around half a second quicker than what he managed yesterday

09:53 Ricciardo has completed his first flyer since the red flag: a 1m24.884s to move up to sixth

09:54 @MyCaterhamF1: Adjustments made and Vitaly's back out on track for run three.

09:55 Hamilton down to a 1m24,160s, as Petrov does indeed heads out for Caterham

09:56 @InsideFerrari: After two hours of track time, Fernando has completed 17 laps, the quickest in 1.23.640. Today's programme is still aimed to acquire data.

09:57 Rosberg, Ricciardo and Hamilton are all on mediums

09:57 But Hamilton pits

09:58 Good little battle between Rosberg and Ricciardo - less than two seconds between them, and very evenly matched on laptimes

09:59 Petrov improves by some 10 seconds with a 1m29.865s. He's still at the bottom of the times

09:59 @AussieGrit: Off to Barcelona testing, looking forward to seeing the boys again, o and the 8.

10:00 We assume "the 8" is the RB8

10:00 Perez with a 1m24.188s, enough to displace Hamilton and go fourth

10:01 It's Petrov, Perez and Rosberg on track now

10:02 A further improvement for Petrov: 1m28.812s. Now less than a tenth behind Pic

10:02 Practice stop for Ricciardo, and he's back in the fray

10:03 Pic heads back out in last year's Virgin/Marussia

10:05 Our @eddstrawF1 reports that Toro Rosso's earlier stoppage was an out of fuel run

10:05 Teams do this to know exactly at what point they start to get fuel starvation problems

10:05 Meanwhile, Alonso is on track and about to start a flying lap

10:06 After 12 laps, Petrov returns to the pits

10:07 A 1m24.077s for Alonso

10:09 He follows up with a 1m24.453s as Pic improves to a 1m28.092s. The Frenchman is still 1.7 seconds off his closest rival

10:10 Pic has managed 21 laps today, his second day at the wheel of the Marussia

10:11 Hulkenberg returns to the pits, leaving Alonso and Pic on track

10:11 Now Hamilton wants some of that fun and leaves the pits

10:13 A 1m25.132s for Alonso on the fifth lap of the current run

10:14 His average laptime so far is under 1m24s, which is, in Formula 1 terms, decent enough

10:14 The glorious sunshine makes it look hot outside, but the temperature says it's not

10:15 Pic pits now

10:15 1m24.040s for Hamilton, who moves up to third

10:15 Fastest than anyone else today through the S1 speed trap

10:17 Much slower second lap for Hamilton, but again he's fastest in the speed trap - this time in S3

10:18 Perez heads out as Bottas comes across for the first flyer of this run

10:18 Hamilton with a 1m24.844s, but he goes purple in S1. It's sectors 2 and 3 where he has been losing time to the Red Bull

10:20 Alonso is on the ninth lap of the current run, now lapping in the 1m26s

10:20 But he heads into the pits

10:20 Bottas sets a new personal best: a 1m26.250s

10:21 That's around half a second slower than Bruno Senna managed in the FW34 yesterday

10:21 Pastor Maldonado will take over from Bottas tomorrow to drive for the last two days of the test

10:22 Another overall best in S1 for Hamilton, but he's slow in S2 and S3 and ends with a 1m25.279s

10:23 Hamilton pits, ending a five-lap stint averaging 1m27.096s

10:23 Perez, Ricciardo and Bottas are out on track

10:25 We apologise for not having answered your questions today, but there's a virus that seems to be chasing the AUTOSPORT staff and is making things slightly more difficult

10:25 Perez heads into the pits

10:27 It's only Bottas and Ricciardo on track at the moment, both lapping rather slowly

10:28 We would like to ask F1 teams to tell us what their drivers are having for lunch today

10:28 Please mail us at live@autosport.com. Not mailing us will mean bad luck during the season...

10:29 @Marussia_F1Team 25 laps on the board and time for a break to review progress in the nerve centre #F1 yfrog.com/h8ne0duj

10:30 Ricciardo heads in and dives into his pit bay, where his mechanics get to work in a pitstop simulation. He pulls away, but after 20 yards cuts it off and is wheeled back in

10:32 Look at Hulkenberg go. He has moved up to second with a 1m23.244s, less than two tenths off Vettel's pace

10:33 Like Hamilton, the Force India driver seems to be finding time in S1

10:34 But then losing it in S2 and S3, where the Red Bull seems to be the strongest car

10:35 Nonetheless another solid effort for Hulkenberg, who was second quickest yesterday. Today he has gone some two tenths quicker

10:35 Rosberg meanwhile drops down to a 1m24.730s

10:35 He's still down in seventh, though, 1.6 seconds off Vettel

10:37 Only Rosberg and Hulkenberg are on track right now

10:38 Here's an interesting shot of a how teams use a low-tech method to apply flo-biz

10:40 @eddstraw reports: Quick update on Williams. As Bottas will be driving on 15 Fridays this year, the team is trying to give him some experience of the kinds of programme he will be expected to run during free practice.

So that means tyre evaluations, a little practice at part evaluation and the usual early set-up work.

A logical move to better prepare him for a role that requires him to make a real contribution to the race weekend.

10:41 Hulkenberg has pitted and Petrov is heading back out in the Caterham

10:41 Gavyn asks: "Thinking about the earlier Toro Rosso stoppage. Do teams have to tell anyone that they're going to be doing a no fuel run and that they will be stopping on track?"

Sam Tremayne says: No, teams are not obliged to tell other teams they will be doing no fuel runs. There is a bit of an etiquette though, given that every team will do them as there is no private testing. Typically teams will try and do them when conditions aren't at their optimum, to try and minimise the impact on others

10:42 Petrov post his best time of the day: 1m26.605s to jump ahead of Pic

10:43 Some readers are angry because they think we will jinx their teams if they don't mail us about their drivers' lunch

10:43 We apologise to them. We didn't know we could affect the performance of the teams from here

10:44 Hamilton has jumped back onto the track for another run

10:46 Petrov and Pic running in the 1m30s and 1m32s respectively. Rosberg is also on track running in the 1m26s

10:48 Risto Havia of Helsinki asks: Is there an old engine (2011) in Marussia?

Sam says: Marussia is running a complete 2011-spec car in the second test - which means everything from engine to chassis and front wing. They intend to bring their 2012-spec car to the final test, also at Barcelona, on 1-4 March.

10:48 Hamilton and Petrov have pitted

10:48 And now Rosberg too, leaving Pic alone

10:49 The French rookie is lapping in the 1m29s at the moment

10:51 Although there has been no confirmation of the Marussia launch, we understand that there will just be a roll-out launch on the morning of March 1

10:52 A reader has threatened to chase us down if McLaren's season goes bad over the lunch mails. We like committed F1 fans.

10:52 Back on track, Hamilton, Perez and Ricciardo join Pic

10:54 Meanwhile, pace-setter Vettel has been in the Red Bull garage for over an hour now

10:55 Perez crops up with a 1m23.541s in the Sauber

10:55 That puts the Mexican in third place, less than half the second behind Vettel

10:56 Ricciardo into the 23s now too - he jumps Hamilton and moves to fifth with a 1m23.986s

10:56 Hamilton won't respond to that just yet. He heads back into the pits

10:57 After his flyer, Perez posts a 1m32.661s

10:58 Now the Sauber driver has picked up the pace again, posting a 1m23.600s, just shy of his previous best

10:59 By contrast, Ricciardo has posted a 1m24.897s

11:00 The banner patrol has missed a lot of the action today: there are four new additions in the main grandstand

11:01 Two are supporting Alonso, one says 'Forever Ferrari' and the last one is impossible to decipher

11:01 And speaking of Alonso, he is now on track, much to the delight of the crowds

11:01 Another practice start for Ricciardo, who makes it 20 yards out the box before stopping

11:03 Former Toro Rosso race driver and Red Bull's reserve Sebastien Buemi is following the action from the pit wall today

11:03 Hamilton heads out of the pits again

11:03 It's now less than one hour until lunch time. We can't wait

11:04 Hamilton comes straight back into the pits

11:05 Bottas sets his best time of the day, a 1m25.858s that keeps him in eighth

11:06 Some F1 news:

Brawn: Teams will regret FOTA split

11:06 Rosberg exits the pits as Hulkenberg heads round for the start of his flying lap of this run

11:06 Great consistency again from Bottas - this time around he is just 0.037s off his previous

11:07 Perez goes quicker again, and ends up just 0.006 seconds off Vettel's best

11:07 Personal bests, but no overall bests, in all three sectors for the Sauber driver

11:07 Hulkenberg is also on it - he comes round in 1m23.141s

11:08 The top three drivers are covered by less than a tenth of a second now

11:09 Vettel, however, has managed less than half the laps done by Perez and Hulkenberg. The world champion has not been on track since 10:47am

11:10 The three busiest men today - Hulkenberg, Rosberg and Bottas - share the track. The Williams driver is the first one to reach 50 laps today

11:11 @InsideFerrari: Again we're workin on different exhaust layouts: interesting job but a bit time consuming...

11:12 Hulkenberg pits after a lap in the 1m24s

11:13 The Force India driver has made solid progress this morning, and is now on 52 laps

11:14 Meanwhile, Mercedes is reporting to be happy it is making through its technical programme with the new W03. The team waited until about 11 before doing serious running because of lower track temperatures to avoid wasting tyres.

11:15 Now approaching 1000 km with the new car

11:15 Alonso heads back out for another run

11:16 @MyCaterhamF1: Rear anti-roll bar and torque map changes made for Vitaly's next run. He's back in the cockpit and ready to go.

11:16 Alonso is running on softs at the moment, as Hamilton leaves the pits

11:17 Hamilton on hards, but any chances of a (semi) interesting comparison is ruined as he pits straight away

11:18 Alonso clocks a 1m24.177s on his first flyer of this run

11:19 @MikeGascoyne: Vitaly much happier in the car, starting some setup work now to help the balance for him

11:20 A 1m24.943s for Alonso now

11:20 Pic, Petrov and Ricciardo share the track with the Spaniard

11:22 Alonso posts a discreet 1m25.682s on the third lap of the run

11:23 Perez and Hulkenberg jumped onto the track as Ricciardo stops in the pits

11:25 Salil asks: Do the teams do a real time pitstop during the testing also?

Our pitstop expert @eddstrawf1 says: Yes, they sometimes do those during race runs. However, often during race runs they might do a more leisurely pitstop because there's no real need to do a full-blown race one.

11:26 Hulkenberg flies to the top of the times with a 1m22.608s

11:26 Perez has also improved, moving up to second and relegating Vettel to third

11:27 Hulkenberg's time is the best set this so far by quite some margin. He's just nearly half a second ahead of Vettel

11:28 Alonso, meanwhile, is lapping in the 1m27s

11:29 Weather update time: air temperature is 13.1C while track temperature has risen to 32.2

11:30 With 30 minutes to go before lunch, all drivers are back in the pits

11:31 We are sorry to report no F1 team has mailed us about their lunch plans. We know million of fans are eager to know

11:31 Hamilton breaks the silence and heads out in the McLaren

11:33 Hulkenberg's time is over half a second quicker than what Vettel managed yesterday. But it's still far from last year's best during testing: 1 m21.268s, set by Michael Schumacher

11:34 Hamilton pitted without setting a time, as Rosberg takes his place on the track

11:35 We are trying to find out what is wrong - if anything - with Vettel's Red Bull, as he has been in the garage for nearly two hours now

11:36 Perez and Ricciardo join the track

11:37 1m23.783s for Ricciardo, who moves up to fifth in the Toro Rosso

11:38 Rosberg and Ricciardo are on softs

11:38 Perez improves his laptime, but not his position. He is just 0.040 seconds off Hulkenberg

11:39 Rosberg overtakes Bottas and Hulkenberg as the man with the most laps, the German now on 58 in the Mercedes W03

11:39 Bottas didn't like that, though, as he leaves the pits

11:40 Perez is running on supersofts (this picture is from earlier)

11:41 Vettel finally heads back out

11:41 Just 21 laps for the German this morning, the fewest so far

11:41 Bottas is running on medium tyres

11:42 Hamilton is also no track as we enter the final 20 minutes of the morning session

11:43 Vettel is running on the medium tyres, but his first lap is a slow 1m37.355s

11:44 Perez pits after posting a 1m23.610s. There are another five cars out on the circuit

11:44 Pace-setter Hulkenberg leaves the pits in the Force India

11:45 A 1m32.956s for Vettel, who seems to be checking things rather than trying to set a proper laptime

11:46 The two fastest times so far were set on super softs. We thought you'd like to know. Vettel's time, we believe, was set on mediums

11:47 Vettel has pitted

11:47 Petrov and Pic join the action, and it's only Alonso, Perez and Vettel in the pits

11:47 @OfficialSF1Team: #Sauber and #Checo had a good morning. Over 50 laps, the fastest was 1.22,648 on super soft tyres. Now lunch break. http://t.co/gPo7vqaf

11:49 More F1 news to keep you busy:

Ricciardo upbeat about Toro Rosso form

11:49 Hamilton returns to the pits. Six drivers still on track though

11:50 But none of them are going too quickly, Hulkenberg the quickest man in the 1m25s

11:50 Ricciardo leaves the pits as we enter the final 10 minutes of the morning session

11:52 Lotus is enjoying the lunch break too, although the team is not running at Barcelona anymore this week

@Lotus_F1Team: It's that time! The @Lotus_F1Team #lunchbreakteaser ! Kimi #Raikkonen currently holds the lap record at 5 #F1 circuits; can you name them?

11:53 Hulkenberg is back into the pits after a 1m25.661s lap

11:54 Ricciardo sets his personal best, moving up to fourth. First and third sectors were his best, but didn't do his best second sector

11:54 The Australian is currently running on the super soft Pirellis

11:54 Alonso is out on softs

11:55 Pics pits with five minutes of the session left

11:56 Vettel improves, going into the 1m22s

11:56 1m22.891s for the world champion, using the soft tyres

11:57 Alonso has pitted, and so has Bottas. That seems to be the end of their morning session

11:57 Vettel stops too

11:58 Vettel's lap had the fastest third sector of all - a 29.503s - plus a personal best in sector one at 21.859s. His second sector was not too good though

11:59 @WilliamsF1Team: 69 laps completed by Bottas this morning as we go into the lunch break. He's now talking with his engineers before jumping out the car

11:59 More drivers coming into the pits now for their lunch break

12:00 Just three men left on track

12:01 The busiest man this morning will be Rosberg with 73 laps completed. A decent haul

12:02 The flag is out to mark the end of the morning session

12:03 So Nico Hulkenberg leads the way at the end of the morning session, following by Sergio Perez and Sebastian Vettel. The two fastest times set on super softs

12:04 We will be back in an hour for the afternoon session. Stay tuned!

12:57 Right then, hopefully you're now well fed and your desk/sofa/chair is well stashed with tea and cakes for the afternoon session which will begin shortly

12:59 If you get time and you're a subscriber, don't forget to cross over to have a browse on the premium feature section of the website. We are currently running plenty of interesting stuff from Barcelona including an insightful look at Mercedes chances this year.

Mercedes: Sharpening the Silver Arrow

13:15 Remember Sebastian Vettel was impressed enough to say something publicly about the McLaren's long-run form yesterday - though one supposes it could all be a clever ruse to play his own team's potential down...

Sebastian Vettel says he is impressed by long run pace of new McLaren Formula 1 car

13:43 @InsideFerrari reports: It will be a slightly longer lunch break as we are working on a change on the car

13:44 The Toro Rosso is being brought back to base now, so we should be live soon.

13:46 We're green again.

13:49 Vettel pits then heads straight back out again, as Red Bull team principal watches on from the pitwall.

13:51 Petrov begins the first flyer of this run.

13:52 Perez pops in and out of the pits as Bottas records 1m27.189s lap.

13:54 Caterham's Petrov completes his latest lap - a 1m29.841s - and in doing so records the fastest speed of the afternoon through the S3 trap.

13:57 Hamilton heads back out on to the track in the McLaren.

13:59 Vettel is now on to the sixth lap of this run and each one has been in the 1m29s so far.

13:59 Petrov comes back into the pits - the Russian has completed 43 laps today now.

14:00 Hulkenberg is also back in his box.

14:02 Bottas just recorded a 1m28.222s on the eighth lap of this run for Williams - that's just .060s quicker than his seventh lap - how's that for consistency?

14:04 The Finn drops into the 29s on his ninth lap only to bounce back with a 1m28.550s on lap ten.

14:05 Finally the GP3 champion pits from that fairly long run. He's currently eighth fastest overall.

14:05 So that leaves Vettel, Hamilton and Pic all on track.

14:11 Vettel pits for fresh rubber as he exchanges softs for mediums. That was a ten lap run for Vettel then which averaged at 1m29.942s.

14:13 Our roving trackside expert, @eddstrawF1, says that the McLaren is looking very strong down at Turn 1. 'On the power fractionally before Vettel and can be very aggressive on braking and turn in.' Both cars look very good though he reports.

14:17 Petrov and Hulkenberg back out on track.

14:17 Interestingly, Hamilton did a nine lap run - compared to Vettel's ten, by the way.

14:17 Less than 0.1s between the pair's average, and both were on softs.

14:18 Long runs seem to be the order of the afternoon, as was the case yesterday.

14:20 Alonso and Bottas head out on to the track.

14:22 Red Bull appears to be using the Mercedes-inspired wheel-nuts-attached-to-the-rims idea. One didn't seem to thread to well on the world champion's stop apparently.

14:23 Alonso is back in the pits already, he's still a fair way off his targetted 100 laps a day quota (53). He's got just under a 100 minutes left to do the other 47 then...

14:23 Petrov is currently almost 20k/mh faster than Hamilton through S1 and S3, but five seconds a lap slower.

14:27 Alonso pops in the pits again. The Spaniard doing sporadic, exploratory laps at the moment.

14:29 Most people are on long runs at the moment. So that means no 'Holy Banjo!' headline times to scream about right now, but there is a lot of work being done. Alonso has come back in and out of the pits again. Only the stranded Ricciardo has done less laps than the double world champion so far this afternoon.

14:30 That's if you're not counting Lotus and HRT of course. One's gone home and the other isn't here.

14:31 AUTOSPORT's Sam Tremayne says one of the unused access roads would be a good place for a lazy afternoon snooze as the surface temperature reaches 31 degrees C!

14:33 Vettel's second stop is much smoother and he shoots back out of the pits without delay. Incidentally, if you think the surface temperature is better or worse where you are - do let us know at live@autosport.com. We like a bit of weather here.

14:34 Interesting spread of compounds being used on track at the moment. Hamilton and Bottas are on softs, Vettel is the only driver on mediums, while Hulk and Petrov are using hards.

14:36 Hopefully that tyre update has answered Matthias Daubitz's (from Berlin) question about what compounds everybody is on. And thanks for the compliments Matthias!

14:38 Given that Vettel has stopped twice, it's possible he is on some kind of race simulation. He's been running for more than 50 minutes now.

14:40 Bottas comes in and Alonso goes out, as Sam [Michael Fish] Tremayne delights in reporting 17 degree sunshine that swathes across the grandstand. 'Good times' apparently. We're not working him hard enough obviously.

14:41 Hamilton and Hulkenberg returns to the pits, leaving just Vettel and Alonso out there.

14:42 Alonso is lapping in the 1m24s, Vettel in the 1m27s. They've both now been joined by Perez.

14:43 Sami from Finland reports that the track temperature in Finland is currently -2.1C. Don't let that stop you keeping your foot in Sami!

14:46 Alonso is using hard compound tyres at the moment, and his most recent lap time was a 1m26.301s. Hamilton and Vettel are both on mediums. Perez meanwhile has gone on to super-softs.

14:47 Alonso stops in the pits again after a four-lap run this time.

14:48 There is excitement on the start straight as Perez and Hamilton blast by the media centre windows. The Mexican is going faster than the McLaren man it would seem.

14:49 Ian Smith, from South Africa, says the track temp was 54 degrees C when he raced at Welkom at the weekend - we think that might be the winner.

14:50 @OfficialSF1Team reports: All is going well - a couple of longer runs are remaining on today's job list for #Checo with the #C31.

14:52 Vettel is almost certainly on a race simulation we think. He's stopped again following his third stint and is back under way again. He's been running for 65 minutes now.

14:52 Perez pits, and we now have Hamilton and Vettel out on circuit, both on long runs - and with less than 3s between them.

14:53 Vettel is 2.5s quicker that time around, and the gap is therefore minimal as the pair head down the main straight.

14:56 Hamilton stays ahead of Vettel this time, the pair are pretty much nose-to-tail. It's only testing but you feel this battle has a slight edge.

14:56 Vettel is on hard tyre incidentally while Hamilton is on more worn mediums.

14:57 We've not seen much of Rosberg and the Mercedes and for those asking why - we are attempting to find out.

14:57 Ditto Toro Rosso.

14:58 AUTOSPORT's Tremayne is getting quite heated about the Vettel/Hamilton tussle. 'This is decent actually' he reports.

14:58 'About a car length between them, with different tyres on each car, and Hamilton just about keeping Vettel at bay'.

15:01 The disappointment in the press room is audible as the battle comes to an end. Vettel passes Hamilton and pulls away.

15:03 In the meantime Alonso pitted after another short stint - he was on hards - and Pic is out on softs in the Marussia (that was a Virgin last year). Speaking of whom, @EddStrawF1 interviewed the Frenchman for our premium content section earlier...

Charles Pic: Not your regular pay driver

15:16 F1 Racing's @jrobertsf1 backs Sam's theory though saying that Perez has pitted and that his car sounds 'Very wonky'. Deeply technical this.

15:17 Right, back to the action. Alonso is currently running on a set of hard tyres, as are Petrov and Vettel. Hamilton meanwhile is on the mediums.

15:21 So Hamilton has now broken the 100 lap barrier and has in fact completed 101 of them. Vettel meanwhile has done 94 - the latest of which was a 1m25.216s.

15:22 Vettel pits again. Then leaves the pits again.

15:24 Only three teams under 80 laps today - Caterham (69), Ferrari (68) and Toro Rosso (45). Looking less likely the Scuderia will hit Alonso's magic 100 now with only 36 minutes to go.

15:27 Ooh excitement. Bottas records a personal best for Williams with a 1m25.738s. The Finn is currently eighth in the standings and he achieved that time on his 103rd lap.

15:28 Pic pits for Marussia, one lap short of his century for the day.

15:29 Hamilton dives into the pits, 52 laps in that long afternoon run, (assuming that is that it's over).

15:30 The Briton has now completed 106 laps today, that's more than anyone, though Bottas is creeping up fast on a 105 and the Finn is still on track.

15:33 Just Hulkenberg and Bottas out there on track currently.

15:35 Hamilton has returned to the action, but it's now Bottas - on 109 laps - that has done the most running today.

15:38 The McLaren man is the fastest man on-track right now. His latest lap was a 1m26.975s.

15:40 We were right about the 'wonky' Sauber sound, by the way. @OfficialSF1Team reports:#Sauber F1 Team pit crew is busy again - an exhaust problem needs to be fixed.

15:41 Alonso leaves the pits.

15:43 Lewis is still out there and moves on to 112 laps with a 1m26.647s laps. This has been another solid day for McLaren.

15:44 Hulkenberg pits, leaving just Alonso, Hamilton and the ever-more experienced rookie Pic out there.

15:45 If we don't get that Mercedes info to you before the end of commentary, don't forget to keep checking the news on AUTOSPORT.com because the chances are it will appear there when our roving reporters report back from wherever it is they've roved to.

15:46 Alonso wakes up the Spanish crowd by setting a personal best with less than 15 minutes of the session to go. His 1m23.180s jumps him to fourth in the standings.

15:48 So it looks like that problem on the Toro Rosso may have been day-ending as there remains no sign of the STR7 in the closing stages of the afternoon's running.

15:49 Hulkenberg's out. Could he go even faster in these final laps?

15:51 Alonso's pitted again and gone back out.

15:52 Pic posts his personal best - 1m27.343s - which doesn't remove him from the bottom of the times, but does move him within a second of Petrov.

15:53 Only Petrov, Perez and Rosberg in the pits now, and two of those we haven't seen for a while.

15:54 Alonso is in and out of the pits again, but he is bolted to a set of super-softs so it's possible we may yet see something special.

15:56 His latest lap was a 1m25.380s so don't get your hopes too high.

15:56 Hulkenberg comes in the pits, as does Hamilton.

15:57 Just Bottas, Alonso and Vettel out there now.

15:59 It doesn't like we are going to see any massive changes then.

15:59 As Hulkenberg returns to the pits having recorded a 1m32.249s that time around.

16:00 And the flag falls.

16:01 Worth reporting thought that both Perez and Ricciardo made it back on to the track in the final stages after their problems this afternoon.

16:02 In the end though, no one could match Hulkenberg's super-soft shod time from the morning in the Force India, so the German stayed fastest with a 1m22.608s lap.

16:03 That's 0.040s quicker than Perez could manage in the Sauber, also from this morning - remember he had an exhaust issue in the afternoon. Vettel ended the day third having successfully completed a race simulation, while Alonso moved up to fouth in the end having completed 86 laps for the day.

16:05 So that's it. Thank you for following us on the Live Commentary today. We hope you enjoyed it and that you will come back tomorrow when it all kicks off again at 0800 GMT and 0900 CET.