07:55 Good morning and welcome to AUTOSPORT's live, Day 2 coverage of Formula 1's final pre-season test!

07:56 Once again today, it's BEN ANDERSON, LAWRENCE BARRETTO and MITCHELL ADAM bringing you the action as the season-opener edges ever closer.

07:58 Williams claimed top spot yesterday, with Felipe Massa setting the fastest time we've seen at Barcelona all winter, while Mercedes experienced a rare troubled day and McLaren was limited to just seven laps.

Felipe Massa fastest on first day of final test

07:58 The new Force India breaks cover today, although not until the afternoon, so we'll have nine drivers in action:

Mercedes - Rosberg
Red Bull - Kvyat
Williams - Bottas
Ferrari - Vettel
McLaren - Button
Force India - Hulkenberg
Toro Rosso - Verstappen
Lotus - Maldonado
Sauber - Nasr

07:59 We're about to go green, weather is remarkably pleasant and will warm up from its current 8C.

08:00 And we're underway. A handful of cars waste no time in taking to the circuit, including Vettel, Rosberg, Maldonado and Verstappen.

08:02 Bottas and Nasr have now left the pits as Vettel completes his installation lap.

08:04 Kvyat's now out as well, as Rosberg, Verstappen and Bottas continue to circulate beyond a token installation lap.

08:06 Verstappen and Rosberg log the first times of the day, a 1m56.933s and 2m03.183s respectively.

08:07 Button has also now left the pits. It's a big day for McLaren-Honda, after being limited to just seven laps (and one timed lap) yesterday. This time in two weeks, free practice in Australia will be complete.

08:09 Rosberg's Mercedes has an aero rake attached, so the focus is likely to be on data gathering and constant speed runs early on. The German currently has the track to himself.

08:12 Button has completed two laps and we've currently got all eight cars in pitlane after the initial run of installation laps. The Force India is expected to break cover this afternoon.

08:15 @SauberF1Team "Questioning why we have a more colored car? This is part of our aero measurements #F1"

08:16 Nasr is in the Sauber today, taking over from Marcus Ericsson, who logged 122 laps yesterday and set the second-fastest time during a late run on the super-soft tyre.

08:17 Maldonado has just been out for a tour of the circuit and returns to tag in Vettel, who has left the Ferrari garage.

08:21 We've got a battle of the aero rakes in the pits, with Vettel heading back in with one attached to the side of his car just as Kvyat leaves the Red Bull garage with two.

It's pretty cold at the Circuit de Catalunya, with track temperatures just 10C, so expect teams to focus on data collection early on.

08:22 Carlos Sainz Jr might not be in the car today, but that doesn't mean a day off. The Spaniard is up early and sat on the Toro Rosso pit wall, chatting to his engineer.

08:25 Felipe Nasr starts putting the Sauber through its paces, the Brazilian clocking a 1m27.965s to go quickest.

08:26 Button has returned to the garage after logging his fourth lap of the day, all within the first 30 minutes. It's been a relatively productive start for McLaren after a Thursday to forget.

The team was also at the centre of one of the day's bigger news stories, following Fernando Alonso's accident last Sunday. A cautious approach will be taken with the two-time world champion's health, which means McLaren's unsure if he'll race in Australia.

08:29 We'll bring you plenty of photos throughout the day from our colleagues at LAT. Here's one of Sebastian Vettel on his installation lap, accompanied by some lovely morning light.

08:36 A Mexican wave has broken out among a group of fans opposite the Mercedes pit as they try to get Nico Rosberg's attention. The German is currently in the garage having completed five laps with just over half and hour gone of the session.

08:37 Valtteri Bottas is also sporting an aero rake on his Williams. The Finn returns to the pits, perfectly hits his marks in the box and then switches off the engine before being pushed back into the garage. No timed lap from him just yet.

08:41 Here's a good look at the double aero rake set-up on the Red Bull of Kvyat a short time ago. Adding, essentially, another tyre width to each side of the car would definitely come in handy if he was trying to defend track position...

08:44 Here's a look at the lap count, 45 minutes into the day. A relatively busy Friday morning with teams gathering aero data in the cold conditions.

Bottas - 11
Rosberg - 8
Nasr - 9
Verstappen - 6
Kvyat - 6
Button - 4
Vettel - 3
Maldonado - 3

08:47 @HondaRacingF1: "Installation laps completed. Team are checking initial data, then testing begins."

Button has managed four installation laps this morning, which is more than half the number he completed in total yesterday.

08:51 Button's just completed another brief run, taking his daily tally to six. With that, the track falls silent.

08:55 @ForceIndiaF1 "This bright garage door hides our new VJM08, which is here at the track and currently being worked on! #FeelTheForce"

09:01 We've currently got four cars on track, and they're relatively close to each other on the circuit. In no particular order, Maldonado, Vettel, Rosberg and Kvyat are all getting down to work.

Of the group, Maldonado and Vettel have set their first times of the day, a 1m30.722s for Pastor and a 1m30.068s for Seb.

09:03 Speaking of times, here's how it looks after the first hour.

1 Felipe Nasr Sauber 1m27.965s
2 Max Verstappen Toro Rosso 1m28.408s +0.443
3 Sebastian Vettel Ferrari 1m29.456s +1.491
4 Pastor Maldonado Lotus 1m30.722s +2.757
5 Nico Rosberg Mercedes 1m38.350s +10.385

Kvyat, Button, Bottas and Hulkenberg are yet to hit the board.

09:11 ‏Media duties at Toro Rosso for Verstappen. But Jos, rather than Max.

@ToroRossoSpy "Hey! That's the wrong Verstappen you are interviewing... @Max33Verstappen is in the car today! :P"

09:12 For the next time it comes up in your local pub quiz, Jos contested six Spanish GPs. His best result was 11th in 1997 with Tyrrell.

That race was won by Jacques Villeneuve, whose last Grand Prix victory came in September 1997, (the Luxembourg GP) two days before Max was born.

Sorry if you remember watching that race and now feel old.

09:14 Out on track, Rosberg has vaulted to the top of the times, with a 1m25.730s on the medium tyre.

09:15 For those of you on McLaren-Honda watch, they've just moved past yesterday's output with Button completing an eighth lap.

09:26 We've currently got Bottas, Maldonado and Vettel circulating. Here's how the overall lap tally looks.

Vettel - 22
Bottas - 20
Rosberg - 18
Maldonado - 18
Nasr - 17
Kvyat - 14
Verstappen - 13
Button - 8

09:29 Enjoying the Barcelona pics? Why not check out a gallery full of them? Here's some of the opening day highlights.

Barcelona F1 testing gallery

09:34 We've got a laptime and double figures from McLaren. On his 10th lap, Button logs a 1m28.868s.

09:39 As Button continues, six laps into this run, Bottas has improved to a 1m26.790s.

09:42 Today is already working out much better for McLaren, with Button pitting after a seven-lap run on the mediums. That was the same amount of laps he completed in total yesterday.

09:51 Bottas dives into the pits after a run on the hards. Meanwhile, MITCHELL ADAM reports from the roof that Rosberg is on the mediums, with his pitboard counting down from nine after his first lap out of the pits.

09:55 Vettel cruises out of the Ferrari garage and heads out on track to join Maldonado and Rosberg.

09:58 Rosberg is remarkably consistent on his current run on the medium tyres, lapping in the mid to high 1m26s. He's onto lap five of this stint.

10:03 Verstappen headed out to put the new Toro Rosso through its paces.

Yesterday, his team-mate Carlos Sainz Jr was full of praise for the car. "It felt different, it felt really good to be honest," he said.

"That's why I want to congratulate all the guys back at the factory for the great job they have done because out of the box I already felt it is a step forward, a more complete package."

10:05 Rosberg pits after that nine-lap run, improving his leading time to a 1m25.365. That leaves Nasr and Vettel with the track to themselves.

Vettel is up to 34 laps for the day already and is currently lapping in the low-mid 1m30s.

10:08 Here's the latest lap count:

Vettel - 36
Maldonado - 33
Bottas - 33
Rosberg 30
Nasr - 29
Verstappen - 23
Button - 15
Kvyat - 14

10:12 Bottas is back out and improves to a 1:26.032 in the Williams, 0.667s off the pace set by Rosberg. Vettel is still plugging away in the Ferrari, although his lap times have dropped into the low 1m31s.

10:15 Posted with the disclaimer that it is testing and fuel loads and set-ups are unknown... a trip up to the roof during Rosberg's last run provided a little visual guide as to the speed of the Mercedes.

With both drivers on the medium rubber, Rosberg passed Vettel then gapped him by the length of the main straight within about five laps. The Ferrari was also shifting up a fair bit further down the straight than the Mercedes.

10:17 The outdoor adventure also featured a single, mysterious drop of rain, despite the sky being clear at the time.

There has been some talk of another rain shower - yesterday's running in the hour before lunch was significantly affected - during the day and the level of cloud cover has been gradually increasing.

10:18 For those of you on our mobile site or app, here's the full times, awaiting entries from Kvyat and Hulkenberg:

1 Nico Rosberg Mercedes 1m25.365s
2 Valtteri Bottas Williams 1m26.032s +0.667
3 Felipe Nasr Sauber 1m27.965s +2.600
4 Pastor Maldonado Lotus 1m28.153s +2.788
5 Max Verstappen Toro Rosso 1m28.408s +3.043
6 Jenson Button McLaren 1m28.868s +3.503
7 Sebastian Vettel Ferrari 1m29.456s +4.091

10:23 F1 Racing editor Anthony Rowlinson is trackside and he's not the only one.

@Rowlinson_F1 "This is Norbert Vettel, Seb's dad, watching his boy testing"

10:27 Felipe Nasr is circulating in the Sauber as he prepares to make his Grand Prix debut in fortnight.

Team-mate Marcus Ericsson was in the same boat 12 months ago, with Caterham, and is well aware of Sauber's famous F1 alumni.

"For the whole history of Sauber they've helped a lot of young drivers get established in Formula 1 and become great Formula 1 drivers," the Swede said during last night's media briefing.

"Of course, I aim to do the same thing here. I can see why that happens because it's a very professional team, very strong structure in the team. It gives the drivers the confidence to improve themselves as well."

10:28 Max Verstappen pops the Toro Rosso into third with a 1m26.957s, 1.592s off the pace.

10:32 Speaking of young Max, he's actually already got some fans in the grandstand. It's not a great pic of them, but three chaps are flying the flag for the 17-year-old.

All just 13 months after BEN ANDERSON wrote that he could make the big leap from karting to Formula 3...

10:34 Just Rosberg and Kvyat, still yet to post a time, on track at the moment.

10:35 Here's a snapshot of the day's top stories:

* Nico Rosberg sets the early pace for Mercedes, the German clocking a 1m25.365 on the mediums
* Jenson Button and McLaren manage 22 laps, which is three times the number completed in total yesterday
* The new Force India is expected to break cover later today

10:40 Rosberg now has the track to himself, just as Mercedes had many front rows to itself in 2014. According to yesterday's pacesetter Felipe Massa, they're still the team to beat in 2015.

Massa: Mercedes still the F1 benchmark despite Williams form

10:46 World champions Vettel and Button have joined Rosberg - who is settling into a long run - on track. Button has just clocked a new personal best for the day, a 1m28.052s to sit ahead of Vettel on the times.

10:52 Naturally, we'll have more on this as the story develops.

@Rowlinson_F1 "Hearing from a very good source that Manor Marussia F1 will be confirmed on the 2015 F1 entry list later today."

10:54 Jenson Button peels into the pits after a seven-lap run on the mediums, bringing his tally to 29 - that's more than four-times his tally from yesterday.

Here's the latest lap counts:

Vettel - 48
Rosberg - 42
Vertsappen - 42
Nasr - 41
Maldonado - 39
Bottas - 39
Button - 29
Kvyat - 20

11:02 Having been relatively quiet all day, and with Raikkonen yesterday, Vettel has gone P2 on the soft tyre with a 1m25.902s.

11:04 Here's how that affects the times, as we enter the final hour before lunch:

1 Nico Rosberg Mercedes 1m25.365s
2 Sebastian Vettel Ferrari 1m25.901s +0.536
3 Valtteri Bottas Williams 1m26.032s +0.667
4 Felipe Nasr Sauber 1m27.965s +2.600
5 Pastor Maldonado Lotus 1m28.153s +2.788
6 Max Verstappen Toro Rosso 1m28.408s +3.043
7 Jenson Button McLaren 1m28.868s +3.503

11:05 Although, right on time, as that was posted, Nasr improved to a 1m26.408s. He remains fourth.

11:06 @karunchandhok "Vettel's just done his best lap of the day - 6.5 kmh down in straight line speed to Bottas across the start - finish line"

11:13 We've been joined in the media centre once more by KARUN CHANDHOK, fresh from a morning out having a look at the action.

"We went to Turns 1, 2, and 3 to start with and the Mercedes looks awesome through there. It's got great driveability out of Turn 2 and good aero balance through 3.

"Rosberg looks like he's driving quite under the limit, but is still quick.

"The McLaren front end turns in really positively and Button looks like he’s able to place the car quite comfortably where he wants, but whether that's because he's going slower because of the engine is a question mark."

11:17 @ForceIndiaF1 "A flurry of activity in the garage and a growing number of cameras outside it - it can only mean the moment the VJM08 heads out is close!"

11:18 Of those already on track, Nasr improves again to a 1m26.113s, and we've finally got a time from Kvyat - a 1m29.323s that will surely be bettered before long.

11:20 Vettel goes top, with a 1m25.339s on the soft rubber.

11:21 The Force India VJM08 is heading out for its maiden voyage.

11:21 And duly straight back in following an installation lap.

11:23 In the context of only running two-and-a-half days of this test with the new car, getting that installation lap in before lunch is handy, essentially buys Force India an extra hour for checks and to deal with any problems that may arise.

11:30 Nasr goes top on the soft rubber, with a 1m24.479s.

11:32 We're half an hour from lunch and the new Force India has broken cover, here's the latest.

Force India's VJM08 2015 Formula 1 car makes track debut in test

11:40 On another soft tyre run, Nasr improves by almost half a second, to a 1m24.071s.

11:41 It's been a productive morning for most of the teams and - in a testing rarity - we're yet to see a red flag. Here's the latest lap count:

Vettel - 66
Verstappen - 64
Nasr - 58
Rosberg - 53
Bottas - 52
Maldonado - 39
Button - 35
Kvyat - 26

11:44 We're approaching the lunchbreak, so it's time for another social debate via #autosportf1.

Today's theme is your favourite F1 season.

What's the one year you could happily watch the highlights from again and again? The title battle and storylines that captured your imagination more than any other?

Let us know with the #autosportf1 hashtag and we'll publish a selection of the best here in AUTOSPORT Live over the lunchbreak.

11:49
When Force India's new car turned a wheel for the first time, Sergio Perez was among the interested onlookers.

He'll get behind the wheel on Sunday, with Hulkenberg driving this afternoon and tomorrow.

Here's Sergio rugged up in his coat and scarf, looking like he's just stepped out of the pages of a fashion catalogue.

A catalogue for people who like to be stylish and accessorise with informative headsets and stay safe behind a barrier.

His team-mate, meanwhile, has now completed a second lap.

11:52 Rosberg has improved to a 1m25.216s, moving back up to second in the process.

11:54 With six minutes until lunch, Button is poised to have turned six times as many laps as he did yesterday. He's on another longer run, up to his 39th for the day.

11:57 Hulkenberg has returned to the track for one more pre-lunch tour.

11:58 The German pushes on and gets on the board with a 1m31.165s.

11:59 And then makes it safely back to the garage.

12:00 Which brings us to the lunch break, as the last couple of cars return to the pits after a busy morning.

12:01 This is how the times look from the morning.

1 Felipe Nasr Sauber 1m24.071s
2 Nico Rosberg Mercedes 1m25.216s +1.145
3 Sebastian Vettel Ferrari 1m25.339s +1.268
4 Valtteri Bottas Williams 1m26.032s +1.961
5 Max Verstappen Toro Rosso 1m26.766s +2.695
6 Pastor Maldonado Lotus 1m28.013s +3.942
7 Jenson Button McLaren 1m28.052s +3.981
8 Daniil Kvyat Red Bull 1m29.294s +5.223
9 Nico Hulkenberg Force India 1m31.165s +7.094

12:03 And the morning workloads:

Verstappen - 78
Vettel - 69
Rosberg - 64
Nasr - 59
Bottas - 58
Maldonado - 50
Button - 44
Kvyat - 36
Hulkenberg - 9

12:06 We'll have a full report online shortly, but here's this morning's running at a glance:

* Nasr fastest with soft tyre run
* New Force India makes debut in hour before lunch
* McLaren bounces back from troubled Thursday to complete 44 laps
* Session runs without incident

12:10 BEN ANDERSON: "Spent some of the morning watching the cars trackside.

"The Mercedes looks a joy to drive, smothered in grip, and the Williams is also impressive - much more consistent and stable at the rear than last year's car.

"The Ferrari wasn't turning in well at low speed, and couldn't carry the same momentum through Turn 3 as the Mercedes, but Vettel was on long runs, so it's possible the car was simply fat with fuel.

"Didn't see much of the Red Bull, but the 'new' Toro Rosso looked decent in Verstappen's hands. He was fighting to control some wheelspin exiting the slower corners, but looked very neat otherwise.

"The Lotus and the Sauber both look tough to drive. Maldonado and Nasr were both fighting the wheel mid-corner and Maldonado particularly was struggling to be consistent through turns one, two and three.

"It was good to see Button rack up some decent laps in the McLaren-Honda. The chassis looks good, but the fact it turns in very well may be accentuated by the engine not running at full power yet.

"The Honda still sounds unrefined compared to the others out there, so (unsurprisingly) plenty of work still to do."

12:25 While the paddock grabs some lunch, catch up with everything you need to know about the morning running here:

REPORT: Nasr fastest as McLaren bounces back

12:29 If you're looking for something a bit different this lunchtime, check out this one-to-one interview with KARUN CHANDHOK on his racing career to date:

12:31 Plenty of votes for 2007 in our #autosportf1 poll of readers' favourite/most memorable F1 seasons.

"It has to be 2007," says @brianlelas, "The whole Alonso/Hamilton and Spygate drama, the fantastic finale..." while @Kimivani has the Finnish slant on that season: "To me it must be 2007 when Kimi won the title!It was just absolute thriller start to finish!Whole finland was happy for Iceman!"

12:37 We like the reasoning behind the #autosportf1 votes for the 1999 season too.

Some nostalgia for @SamStoreF1: "Eight-year-old me loved Irvine and Frentzen taking on the McLarens!"

And @zeromoda sent us a three-tweet epic of reasons: "1999 had it all: A titanic battle between two champions, one champion taken out, an unlikely challenge from his number two, an even more unlikely challenge from a little Irish team, in Monza Hakkinen was human after all, the Nurburgring GP, the Return of the King in ominous form, disqualifications, reinstatements and a title showdown in Suzuka."

It was a bit of a cracker, prompting memories of a particularly long and delirious teenage night shift on a fledgling AUTOSPORT.com on the Malaysian GP weekend for one of us here too.

12:48 An intriguing choice from @Drtimhavard in our call-out for your most memorable F1 seasons:

"My favourite F1 season is an odd one - 1977. Lotus sniffing at ground effect, Scheckter in a Wolf, Villenueve and turbos debut."

Plenty of votes for Ferrari's return to glory in 2000, 2010's five-way title decider and 2012's Alonso/Vettel showdown too.

12:49 Fernando Alonso has issued an update on his recovery after his accident in last week's test, and he says he was keen to drive again this week:

Alonso says he wanted to test this week

12:51 Let's make our Jacques Villeneuve devotee website editor happy, he'll approve of @o_ensan's vote:

"Surely '97? So many teams at the front, and the battle between JV and Schumi with them never on the podium together."

12:55 We're going to round off our whizz through readers' most memorable F1 seasons with @aelfwald's choice of 1991 and its all-star cast.

"Senna, Prost, Mansell, Schumacher, Piquet, Hakkinen driving. Spectacular cars and still some romance left in the sport!"



Thanks for all your suggestions, we'll do another Twitter poll over the lunchbreak on Saturday and Sunday too.

Track action at Barcelona resumes in five minutes.

13:01 Lunch is over. It's time to get back to business. Let the afternoon session begin!

13:04 It's a gloriously sunny day in Barcelona, with air temperatures up to a toasty 12.6C. The track temperatures are up at 24.4C. Good conditions to go testing.

13:07 Sebastian Vettel breaks the silence as he heads out on track in the Ferrari. It was a very productive morning for the four-time world champion, who focused on aerodynamic tests and long runs.

13:12 Vettel is three laps into this run, on the hard tyres, and is lapping in the low 1m29s. The German has just been joined on track by Maldonado and Kvyat.

13:14 As most of you have probably noticed, ex-F1 driver and current Formula E racer KARUN CHANDHOK is in attendance at this test for us.

We're going to get him to sit down at the end of the day to plough through questions from our readers about what he's seen at the test - submit yours using #askKarunF1 on Twitter

13:20 Kvyat moves up to sixth fastest with an improvement on the mediums - a 1m27.257 - before peeling into the pits. The Red Bull mechanics have the screens out to shield the front of the car from a group of snappers.

13:22 Vettel is still ploughing on with his set of hard tyres and is now 10 laps into his run in the Ferrari. He is now lapping in the high-1m29s and low-1m30s.

13:27 Vettel pits after a 12-lap run on the hard tyres. That leaves just Nasr, Maldonado and now Button out on track.

13:29 Here's an early afternoon lap count for you:

Vettel - 81
Verstappen - 78
Rosberg - 65
Nasr - 63
Maldonado - 61
Bottas - 59
Button - 48
Kvyat - 41
Hulkenberg - 5

13:32 Button dives back into the pits after a six-lap run as Kvyat heads back out to join Maldonado, Verstappen, Bottas and Nasr.

13:37 The Force India is out and about for the first time this afternoon, with Nico Hulkenberg running the demo tyres.

13:38 Hulkenberg drops beneath the 1m30s bracket, with a 1m29.866s.

13:40 Vettel and Nasr head out into the afternoon sun. Despite the bright sunshine, air temperature is still 12.7C, although the track temperature is 23.9C.

13:41 Hulkenberg has completed his little run, 10 laps in the book now for the new Force India. Ostensibly trouble-free thus far.

13:48 Button has returned to the track in the McLaren. He's cracked a half century of laps for the day, a much-needed boost for the reformed alliance.

13:51 Vettel looks to be on a long run in the Ferrari, we're tracking it as a possible race simulation as he approaches 100 laps for the day.

The team is gradually introducing aero upgrades during the rest, read more here.

13:52 Nasr is also on a long run. Ericsson completed a race simulation yesterday afternoon, so a repeat wouldn't be a surprise.

13:55 We've currently got eight cars on the track, with Rosberg the odd man out. Or in...

13:56 A variety of tyre compounds and programmes as well. Vettel is on the hards, Bottas mediums, for instance. Bottas has set two green sectors this lap.

13:57 He doesn't add a third green sector, but does improve enough to jump up to second with a 1m24.944s.

13:59 Hulkenberg improves to a 1m29.287s as Vettel joins Rosberg in pitlane, having completed a pitstop on the previous lap.

14:01 It's now 3pm local time, which means we've got three hours of running left for the day. Here are the times:

1 Felipe Nasr Sauber 1m24.071s
2 Valtteri Bottas Williams 1m24.944s +0.873
3 Nico Rosberg Mercedes 1m25.216s +1.145
4 Sebastian Vettel Ferrari 1m25.339s +1.268
5 Max Verstappen Toro Rosso 1m26.766s +2.695
6 Daniil Kvyat Red Bull 1m26.965s +2.894
7 Pastor Maldonado Lotus 1m28.013s +3.942
8 Jenson Button McLaren 1m28.052s +3.981
9 Nico Hulkenberg Force India 1m29.287s +5.216

14:02 And the lap counts:

Vettel - 94
Verstappen - 84
Nasr - 84
Maldonado - 81
Bottas - 68
Rosberg - 65
Button - 58
Kvyat - 51
Hulkenberg - 15

14:08 Thanks for all of the great #askKarunF1 questions. We'll have his answers up later today. And more insight from his trips around the circuit.

14:10 Button has just pitted after a 13-lap run on the medium tyre. He joins Rosberg, Vettel, Kvyat and Hulkenberg in pitlane.

14:11 On softs, Bottas goes fastest - 1m23.995s

14:12 Bottas and the man he replaced at the top of the timesheets, Nasr, look like they're tackling race simulations.

14:13 In Bottas' case, we'll be keeping an eye on his times, as the drop-off on the soft tyre runs yesterday was noticeable.

14:13 @SauberF1Team "Pit stop for Felipe during his race simulation #FN12 #F1"

14:14 So that's Sauber's afternoon sorted.

14:14 However our plan to track Bottas on the soft has come to nought, he's just pitted again.

14:15 Bottas' lap, though, is the second-fastest time we've seen at Barcelona in the last six days of testing behind team-mate Massa's lap yesterday.

14:16 Some breaking news for your Friday afternoon...

FIA approves Manor's Formula 1 return on new 2015 entry list

14:19 A relative moment of calm on track, with Kvyat the only driver on track.

14:20 A red flag will explain that...

14:21 The Red Bull has stopped at Turn 1, according to the circuit information feed.

14:22 The circuit's CCTV has a great view of Turn 2 - and spectators there taking photos of Turn 1 - but hasn't panned ever so slightly to the left so we can view Turn 1 to shed some light on Kvyat's stoppage.

14:25 Not a bad moment to recap the day so far, with two-and-a-half hours remaining:

* Bottas fastest on soft rubber, with second fastest time of all Barcelona testing
* Button logs 64 laps in McLaren-Honda
* Force India appears, turning 20 laps
* Testing runs without red flag for bulk of the day, before Kvyat stops

14:26 Word from LAWRENCE BARRETTO on the roof:

"Kvyat's car is under wraps and being hoisted onto the back of a truck. Can't get close enough to see there is any damage."

14:28 It's been a productive day for teams here in Barcelona, with the first red flag at 3:20pm local time and no repeat of yesterday's rain.

As a result, and also aided by McLaren's better day, we saw 467 laps in the morning session, compared to 257 on Thursday.

14:29 More from LAWRENCE BARRETTO, who is apparently now spying on spies on the roof.

"Lotus, Ferrari and Williams have spotters standing outside the garage looking down the pitlane to keep an eye on the activity down at Turn 1."

14:32 Green flag, we're going again. Nasr, Vettel and Verstappen head out.

14:35 The Red Bull still has four corners on it, beneath the sheet as the team received its unwanted delivery, so one would suggest a mechanical problem rather than incident.

14:39 Vettel and Verstappen have both just completed their 100th lap of the day. All cars on track bar Bottas, Rosberg and the stricken Red Bull.

14:40 The news that Manor has appeared on the 2015 Formula 1 entry list appears to be popular with fans:

@FFranciscojga: "Very good news"

@debbie42000: "Great news-they deserve to be on the starting grid in Melbourne.Good luck to their crew, been a nightmare for them."

@NickieHough1: "Brilliant news - hope they have a really good year!"

@LauraSimpson87: "Great news for not only @ManorF1Team and Marussia fans, but for the sport as a whole"

14:41 At the base of the timesheets, Hulkenberg improves to a 1m28.847s. Within a second of both Button and Maldonado after 22 laps of running.

14:43 LAT's snappers were on the scene as the Red Bull stopped and Kvyat met some new friends in red racesuits and grey helmets.

14:44 Rosberg has now left pitlane for his first appearance of the afternoon.

14:48 Rosberg's on the medium tyre, lapping in the 25s and 26s, as Vettel completes his run on the hard tyre and pits.

14:53 Verstappen is on his 110th lap of the day, equal top with Nasr, and lapping consistently in the 30s. KARUN CHANDHOK liked what he saw of the Toro Rosso youngster on track this morning.

"Through Turns 1, 2 and 3, Verstappen really impressed me. It's the first time I've really seen him live on track and I think he seems to fully justify the hype.

"He was the only one - apart from Rosberg and Vettel - who was able to drive every lap of his run on exactly the same bit of tarmac, which says something.

"A little later, through Turns 5, 7 and 9, he again looked really smooth, really confident and assured in the car."

14:54 On the topic of completed laps, here's the latest count:

Verstappen - 111
Nasr - 111
Vettel - 108
Maldonado - 106
Bottas - 75
Button - 73
Rosberg - 73
Kvyat - 53
Hulkenberg - 31

Lots of big numbers.

14:56 @MercedesAMGF1 "A few mechanical changes to the car to start the afternoon in the garage, but we're back out on track now! @nico_rosberg at the wheel! #F1"

14:57 Rosberg has indeed added 11 laps to his daily tally so far this afternoon.

14:58 Today is comfortably McLaren's most successful day in terms of mileage. The Woking-based team have managed just 203 laps in nine days of testing, with Fernando Alonso achieving their highest single-day total of 59 on day two of the last test in Barcelona. Today. Button is currently on 78 and racing towards a century.

15:00 No real change to the overall times in the last hour, as teams focus on longer runs. But here's a recap for those of you on the mobile site or app.

1 Valtteri Bottas Williams 1m23.995s
2 Felipe Nasr Sauber 1m24.071s +0.076
3 Nico Rosberg Mercedes 1m25.216s +1.221
4 Sebastian Vettel Ferrari 1m25.339s +1.344
5 Max Verstappen Toro Rosso 1m26.766s +2.771
6 Daniil Kvyat Red Bull 1m26.965s +2.970
7 Pastor Maldonado Lotus 1m28.013s +4.018
8 Jenson Button McLaren 1m28.052s +4.057
9 Nico Hulkenberg Force India 1m28.847s +4.852

15:04 We're starting to get a look at some proper pics of the Force India in action. Including this one from LAT. Hulkenberg has completed 33 laps since the car first appeared just before lunch.

15:05 Vettel has rejoined the circuit. Nasr, Verstappen and Maldonado - on their race sims - are the other drivers currently in action.

15:10 A quick pitstop almost beneath us for Verstappen, who continues his afternoon sim.

15:10 In the wake of the mystery surrounding Fernando Alonso's crash in the previous Barcelona test, the FIA is pushing for teams to have to run special cameras in future to help with accident investigations:

FIA wants new cameras for crash data

15:14 Hulkenberg is back on track, running the hard tyre.

15:18 @redbullracing "A pre-cautionary stop on track to check a hydraulic sensor issue. The Team hope to be back running soon. #F1"

15:18 That explains Kvyat's stoppage earlier, still the only red flag we've seen today with about 100 minutes to go.

15:22 Rosberg has returned to the track. He's currently completed 78 laps. With Nasr, Verstappen, Maldonado and Vettel having already cracked 100 laps, we could see Rosberg, Bottas and even Button join them before the day is done.

15:25 Rosberg improves to a 1m319s. As is Mercedes' way so far this winter, he's on medium tyres and not far behind those on softs...

15:27 Button makes a big jump, clocking a 1m26.362s to now sit fifth.

15:30 Button's time came on the soft tyre, and he's set a new personal best for the first sector on this lap too.

15:30 Button doesn't improve on that lap.

15:31 Nasr, meanwhile, has finished his race simulation and has earned himself a Kit-Kat.

15:32 Here's how the lap count looks with 90 minutes of running remaining:

Verstappen - 135
Nasr - 129
Vettel - 120
Maldonado - 118
Rosberg - 84
Button - 83
Bottas - 80
Kvyat - 53
Hulkenberg - 46

15:33 From that group, we've got pacesetter Bottas (recently back from the pits), Button, Verstappen and Hulkenberg on track right now.

15:33 And Vettel, who thoughtfully waited until that last post had been typed to join them.

15:35 There's an engine rumbling below the media centre, which means Kvyat could be getting ready to head back out.

15:35 Button, meanwhile, has pitted to complete that run on the softs.

15:37 Indeed, Kvyat is back in action while Bottas has returned to the pitlane.

15:38 Hulkenberg has now completed 50 laps for the day and returns to pitlane. Reasonable afternoon's work for Force India so far.

15:39 Pre-season is always an incredibly busy time on autosport.com, and we certainly appreciate that so many of you join us for every day of F1 testing to follow our live coverage.

As a small thank you, we're offering you a chance to read GARY ANDERSON's 'blueprint' for Formula 1's future for free - all you have to do is click on the link below:

FREE: Gary Anderson's blueprint for F1

15:44 @MercedesAMGF1 "Soft tyres! For the first time during winter testing. Off you go @nico_rosberg #BackToWork #F1"

15:45 Purple is a colour we're expecting to see a lot of in the coming minutes...

15:46 Rosberg doesn't let us down. Purple in all three sectors, jumps straight to the top with a 1m22.792s.

You'd forgive him for dropping a microphone and saying 'Nico out'.

15:47 Rosberg's lap was 1.2 seconds faster than Bottas went on the softs earlier.

Having spent spent its time on medium rubber, turning times not that far from soft and even super soft runners, that's more than a little bit of a statement from Mercedes.

15:48 Button, meanwhile, has improved to a 1m25.590s.

15:50 Rosberg returns to the pits, here's how the times now look.

1 Nico Rosberg Mercedes 1m22.792s
2 Valtteri Bottas Williams 1m23.995s +1.203
3 Felipe Nasr Sauber 1m24.071s +1.279
4 Sebastian Vettel Ferrari 1m25.339s +2.547
5 Jenson Button McLaren 1m25.590s +2.798
6 Max Verstappen Toro Rosso 1m26.766s +3.974
7 Daniil Kvyat Red Bull 1m26.965s +4.173
8 Pastor Maldonado Lotus 1m28.013s +5.221
9 Nico Hulkenberg Force India 1m28.847s +6.055

15:51 ‏@karunchandhok "Rosberg just came past looking very committed in Turn 7!"

15:57 Yes, testing in February is different to racing in May, but Rosberg's 1m22.792s a damn sight faster than Lewis Hamilton's 2014 Spanish GP pole time of 1m25.232s.

15:58 Rosberg has just left pitlane, you'd think for a second run on the softs.

15:59 He is indeed on softs. There could yet be some more purple rain.

16:00 Purple in the first sector with a 22.867.

16:00 Not purple in the second, about a tenth down on his best.

16:01 Purple in the third, but not an overall improvement. It's a 1m22.802s.

16:03 With an hour left, here's the lap counts for today.

Verstappen - 139
Nasr - 129
Vettel - 126
Button - 95
Rosberg - 91
Bottas - 89
Kvyat - 65
Hulkenberg - 56

16:04 @ToroRossoSpy "Max's day is ends early due to an electrical problem. He's still smiling though... He's happy with his 139 laps!"

16:06 Maldonado has just finished a stint on the soft tyres, improving to sixth with a 1m26.705s.

16:07 Aren't you driving your Formula 1 car around Barcelona right now, Nico???

@NicoHulkenberg "Really excited about the partnership with #RWT in 2015. THX!"

16:09 Hulkenberg is clocking up the miles in the new Force India, into his 62nd lap of the day and first stint on the medium rubber.

16:11 Maldonado is back on track following a brief visit to the pits. It was a car KARUN CHANDHOK noticed while trackside this morning...

"The Lotus looks very edgy, very nervous to drive. I think the drivers are going to be earning their money again this year, unless they can find a solution to make it more comfortable."

16:14 Rosberg has left pitlane for what could be his third run on the softs. Vettel, maldonado, Kvyat and Hulkenberg are also out at the moment.

16:15 No, he's back on the medium.

16:21 After witnessing Rosberg's blistering run trackside, KARUN CHANDHOK suggests it's not all doom and gloom for Mercedes' rivals.

"I was out watching Rosberg's quail run through Turns 7, 8 and 9 and it looked like a properly quick, committed lap. The car was working well.

"I still think that while his lap was seven-tenths faster than Massa's yesterday, the track's had another day of rubber. So I would argue that Williams could probably get within three or four tenths of that time. "

16:25 So as it stands, we've got Rosberg out on the mediums, along with Vettel, Button, Maldonado, Kvyat and Hulkenberg.

16:27 McLaren and Jenson Button are closing on their first century in pre-season testing. Button is out and about and currently on lap 96. At last, the Woking-based team seem to have had a good day.

16:29 Talking about good days, Force India are having a stunner. Nico Hulkenberg has clocked up 73 laps in the new car, which only started running properly after lunch. That's only four shy of Daniil Kvyat, who has been running since the start of play.

16:33 We're into the final half an hour of the day. Air temperature is still 12.6C - it's been around that all day - but the track temperature has dropped to 15.6C, having been up over 25C a couple of hours ago.

16:33 We saw some late runs on soft and super-soft rubber last night, will be interesting to see if anyone does the same today.

16:34 Button, Maldonado and Kvyat have all just left pitlane, as the only cars on track.

16:34 This will be Button's 100th lap for the day. Big recovery.

16:36 It's complete, but through pitlane rather than the start-finish straight. Stops in the pitbay for a few seconds then goes on his merry way again.

16:37 Nasr has also headed out onto the track. He's currently third after his run on softs before lunch.

16:38 Red flag.

16:38 It's Button

16:39 The McLaren-Honda has stopped on the circuit. They were so close to a trouble-free run.

16:41 Looks like it's the exit of Turn 7, but it's hard to tell from this angle on the CCTV.

16:43 The circuit's feed confirms the car is stopped between Turns 7 and 8.

16:43 Still, a big day for McLaren-Honda. Button will end the day having completed 101 laps.

16:44 Speaking of endings, Williams has taken an early mark.

@WilliamsRacing "With 20minutes left of the day we have completed our programme so car is being prepped ready for tomorrow."

16:47 Taking a while to get the McLaren onto the back of the truck. We'll probably go green again with about 10 minutes to go. Currently 13 on the clock.

16:49 The truck's now leaving the scene of Button's stoppage.

16:52 We're on again, with seven minutes left on the clock.

16:55 We've got five minutes remaining, and Rosberg, Nasr, Vettel, Maldonado, Kvyat and Hulkenberg on track.

16:56 Rosberg pits, likely calling it a day with 3 minutes left on the clock.

16:57 Or not, he's rejoined the circuit immediately.

16:57 The other Nico, Hulkenberg, has improved to a 1m28.785s.

16:58 He improves again, to a 1m28.412s as we enter the final 90 seconds.

16:59 Another red flag.

16:59 It's not Rosberg, Nasr or Vettel

17:00 Or Hulkenberg, who had set a personal best through the first two sectors.

17:00 That leaves us with Maldonado, as Vettel has flashed past the CCTV location.

17:00 The Lotus has stopped at the pit entry

17:01 Almost looks like the front wing is damaged or out of place, from the questionable TV image quality.

17:02 That brings us to the end of the day.

17:02 Here's the final times:

1 Nico Rosberg Mercedes 1m22.792s
2 Valtteri Bottas Williams 1m23.995s +1.203
3 Felipe Nasr Sauber 1m24.071s +1.279
4 Sebastian Vettel Ferrari 1m25.339s +2.547
5 Jenson Button McLaren 1m25.590s +2.798
6 Pastor Maldonado Lotus 1m26.705s +3.913
7 Max Verstappen Toro Rosso 1m26.766s +3.974
8 Daniil Kvyat Red Bull 1m26.965s +4.173
9 Nico Hulkenberg Force India 1m28.412s +5.620

17:04 And here's the final lap count:

Vettel - 143
Maldonado - 140
Nasr - 141
Verstappen - 139
Rosberg - 106
Button - 101
Bottas - 90
Kvyat - 84
Hukkenberg - 77

17:07 Our full summary of the day's action will be available in just a few minutes, and there will be plenty of reaction news on our pages through the evening too - as well as KARUN CHANDHOK's answers to your questions about test form so far.

There are just two more days of pre-season running to go, so expect the clearest hints of 2015 form so far over the weekend - and as ever you can follow it all with AUTOSPORT Live from 8am UK time each morning.

We'll also have CRAIG SCARBOROUGH technical analysis of the latest car upgrade, more from Chandhok at the trackside and a couple more free features for you to enjoy.

17:16 Here's the full report from today's session:

Rosberg puts Mercedes clear out front

Thanks for your company on AUTOSPORT Live today, we'll see you back here around 8am tomorrow morning.