07:57 Cold, dark and with the threat of rain - is this really Barcelona? It's the fourth and final day of testing here in Catalunya, and conditions are not ideal.

07:59 There are a few changes of note to take you through. Fernando Alonso hands over to Felipe Massa, while Max Chilton resumes for Marussia.

07:59 And of course Jules Bianchi takes over from Adrian Sutil, his main rival for a 2013 Formula 1 drive, at Force India.

08:00 Rain won't exactly be what the Frenchman would have wished for, although as Adrian Sutil admitted last night, speed might not be the decisive factor in who Force India pick.

08:01 We're green, and Jean-Eric Vergne, Giedo van der Garde and Max Chilton are all straight out.

08:02 Speaking of Sutil, AUTOSPORT was there to hear his thoughts after ending a 15-month absence from the sport yesterday. Read it here.

08:05 There's also an excellent blog about Sutil, press scrums (and bruised ribs) and why the German was more sanguine than exasperated courtesy of Matt Beer, who was in full elbows-out mode.

08:06 @WilliamsF1Team: "The crew all getting ready for a day of pitstop practice! It's very cold though and could be rainy!

"The engineers are out on our new pitwall today..... Freezing already!"

08:07 Eight degrees on track at the moment, while the air is around seven (with a bit of moisture thrown in for good measure).

08:10 10 minutes in, and we have our first red flag of the day.

08:11 Felipe Massa is the only man reported to be out on track...

08:12 And indeed it is Massa who has caused the stoppage. We have an F138 in the Turn 4 (Repsol) gravel.

08:15 Bottas reported the track was very slippery after his first installation lap. Massa seems to have demonstrated the message instead (although in fairness we haven't been able to catch up with incident as the circuit's CCTV operators appear to be missing).

08:15 Aha. We have a low loader, and a Ferrari facing the wrong way around the right-hander of Repsol.

08:19 It's definitely spitting now. Massa's F138 is loaded up and on the way back to the pitlane.

08:21 But not before AUTOSPORT Live grabs a photo. First we brought you Hole-gate at Jerez, now we bring you...erm, Massa at Turn 4. Not as catchy, but all part of the service.

08:22 A speedy recovery and we're green again.

08:24 Blues and greens - it's our first glimpses of Pirelli's new intermediate and wet compounds.

08:26 Webber heads in from his first installation lap, his RB9 shod on intermediates and his rear wing plastered with flow vis.

08:27 Lewis Hamilton is also on intermediates, and becomes the first man to come past the pits to start a flying lap.

08:28 Hamilton stays out and sets the first time of the day, a 1m53.821s.

08:28 Jenson Button now follows Hamilton's lead, meaning Romain Grosjean is the only man yet to go out.

08:30 The Frenchman said yesterday that he feels he has already been able to demonstrate his new approach for 2013. Read it here.

08:30 Hamilton still the only man to have a set a time, and he has just improved with a 1m45.747s.

08:33 Button comes across now, but on a constant-speed run he's not troubling Hamilton - a 2m05.593s his offering.

08:33 Button pits but Hamilton continues. He's on five laps now and has lowered his best to a 1m43.074s.

08:35 Stint over, Hamilton comes in. Grosjean has been out and back, meaning everyone has completed at least one installation lap.

08:36 Van der Garde and Gutierrez are now the only two men out on track.

08:39 We have a guest for you on AUTOSPORT Live - our technical guru Craig Scarborough. If you have a question for him, email us at live@autosport.com.

08:41 Scarbs has been analysing some of the key design concepts and dilemmas teams are facing over the 2013 pre-season already, which we've handily compiled into one running blog. Subscribers can read it here.

08:41 Van der Garde and Gutierrez set their first flyers, both in the 1m48s.

08:45 @Lotus_F1Team: "How wet in Barcelona? This wet."

08:47 @ToroRossoSpy: "As expected, it's raining, but we can still find plenty of work for Jev to do in the STR8. Media Centre bit empty as usual on last test day."

We're still here (and given the weather, we won't be going anywhere soon).

08:48 Valtteri Bottas has morning duties for Williams, with pit stop practice the main order of the day.

08:49 Jenson Button lowers the day's benchmark to a 1m41.409s.

08:53 More improvements - Button gets down to a 1m40.476s, while Grosjean weighs in with a 1m40.870s.

08:56 And again - Grosjean takes over at the top with a 1m40.068s. It's stopped raining, so all the times are being set on intermediates.

08:57 Our second red flag of the day.

08:57 It's for Caterham - van der Garde has gone off at the final turn.

08:58 AUTOSPORT Live had spotted it already (naturally), but a mass commotion in the media centre was also a helpful pointer as photographers suddenly realised there was a dry shot to be had.

09:00 We're not sure exactly what happened at the final turn, but van der Garde has ended up nudged against the barriers just before the gravel turns into grass.

09:02 Not a clear enough description? How about our own version of a media centre spy shot then?

09:03 Van der Garde was on his seventh lap when he suffered that off. We still have six men yet to set a time this morning.

09:03 The CT03 has been loaded up and is on the way back (not exactly a long way to travel) so we should be green shortly.

09:04 And indeed we are.

09:06 AUTOSPORT Live has a roving weather reporter today (if that wasn't bad enough, he's also been deprived of his bike for the day). The wind has died down, the rain has stopped but it's still very cold.

09:08 Hamilton, Bianchi, Vergne and Button all out now.

09:09 As is Massa, returning following his Turn 4 excursion 10 minutes into the session.

09:09 And Hamilton instantly improves - his first effort is a 1m38.206s which puts him top.

09:11 Button and then Massa set new personal bests to go second and fourth respectively.

09:17 Nico Rosberg has just come up to say hello to the AUTOSPORT Live crew and the rest of the media centre, giving photographers another chance to keep dry while working.

09:20 Our third red of the day.

09:20 It's for the Sauber of Esteban Gutierrez, who is in the gravel at Turn 5.

09:21 The Mexican had just set his fastest lap, a 1m39.471s which put him third.

09:22 Our trackside man was on scene (handily) and said Gutierrez just came in too hot and drifted off track and into the gravel bed.

09:23 Our man says there is the slightest hint of a dry line forming.

09:24 The timing screens have just alerted AUTOSPORT Live to the fact we also have a Red Bull stopped between Turns 9 and 10.

09:24 That would be Mark Webber, although that's as much as we know right now.

09:27 As part of AUTOSPORT's paddock traipse, we spoke to Mark Webber about Friday plans if it rained.

"The temperature is seven or eight degrees and there's no sun so there's going to be water on the track," he said. "We'll have a look - we need to see how the new inters are and how the car is in the wet, but I don't think we'll be doing 110 laps..."

09:28 Webber appears to have stopped on the inside of the circuit just after Campsa.

09:31 Could be a busy day for the circuit's rescue crews and AUTOSPORT Live's Recovery Watch. Simultaneous stoppages are being handled admirably: the low loaders are on scene and the cars are being lifted as we write.

09:33 That said, the distance of the RB9 from the CCTV cameras means it's pretty hard to see whether the loader is now moving or not.

09:34 Ah, it is...sort of. Clearly a change of mind as it performs a 180, travels about 20 yards and then reconsiders, turns around and comes the right way down the back straight.

09:34 Recovery Watch can reveal the Caterham was faster than the Red Bull, so once the RB9's low loader has found a gap in the fencing we should be green again.

09:36 @ScarbsF1: "live.autosport.com - are doing an 'Ask Scarbs' today if you a technical question email live@autosport.com."

That's our resident technical expert Craig Scarborough. He will be on our Live chat later today, so get sending your questions, as he says, to live@autosport.com.

09:36 Green flag and we're back underway.

09:41 And no sooner have we said that than we're red.

09:41 Or we should be. Green flags but there's a swarm of marshals, scooters and recovery vehicles down at Turn 5, where Vergne has gone off.

09:41 The red is finally confirmed.

09:43 Once again our trackside man is perfectly placed. Vergne has gone off a little bit further down at Turn 5 than Gutierrez's earlier off, simply understeering off and into the gravel.

09:43 @WilliamsF1Team: "#BOTTAS just doing in- and out-laps as we continue pitstop practice here but we've got another red flag."

09:47 Told you Recovery Watch was busy. The Toro Rosso has already been loaded onto the truck and is moving out of the gravel, with the marshals now brushing over the tyre tracks. As the STR8 heads off, there are still two recovery trucks waiting for the final few stones to be swept off the track.

09:50 We're green again...for now at least.

09:53 @WilliamsF1Team: "While we have a red flag, there's just time to show you a shot of the crew warming up this morning!"

09:53 Looks like the latest Harlem Shake meme to us.

09:54 Despite the offs, conditions are clearly improving. Felipe Massa goes 1.3s clear with a 1m36.568s.

09:58 As well as noting the on-track improvements, we're really enjoying the -guess-the-password confusion opposite as the automatically-store function comes back to bite some of our fellow media.

09:59 The track is drying, and Lewis Hamilton heads out on mediums. His reward is to go more than two seconds clear at the top. Most of the other runners are still on intermediates though.

10:01 Another massive jump from Hamilton. Our trackside man informs us he's the only man near the Turn 1 apex, and that a dry line is very much beginning to form.

10:05 No sign of a hangover from his earlier off for Vergne. His first flyer since his Turn 5 excursion is a 1m36.628s which puts him third.

10:06 It's now only Valtteri Bottas and Mark Webber (who earlier stopped on the exit of Campsa) who are yet to set a time.

10:09 Niki Lauda is 64 today, and in celebration here's a shot of just how much F1 car design has moved on since 1974. You can take a look at our full archive gallery here.

10:12 Gutierrez is now getting slicks working too. He jumps to second on a 1m35.769s.

10:13 Next time around, Gutierrez sets a new best of the day in sector one, but is still 2.6s off Hamilton around the whole lap.

10:14 Massa is also on slicks and goes second with a 1m33.358s.

10:15 Now Massa takes the top spot on a 1m31.298s.

10:16 Gutierrez lost time on his second lap, then improved to a 1m34.286s.

10:16 Another improvement from Massa as he does a 1m30.017s.

10:17 Gutierrez now slithers over the run-off area at Turn 1.

10:17 Webber brought the repaired Red Bull back out on intermediates, did an exploratory lap then pitted again for more inters.

10:18 Gutierrez brings the Sauber back into the pits.

10:18 Massa goes quicker still with a 1m29.835s.

10:19 Webber seems to be making practice pitstops, coming in for another set of intermediates then resuming.

10:20 Another little improvement from Massa as he does a 1m28.785s.

10:21 Now a 1m28.234s from Massa.

10:23 For the first time in a while, Massa doesn't improve. He slips back to 1m28.7s on that lap as Webber makes another pitstop.

10:24 Vergne is now setting off to sample the improving track.

10:27 Massa seems to have hit a plateau. All the track's offering him now is high 1m28s and 1m29s.

10:28 Webber and Red Bull continue with pitstop practice and a bit of intermediate tyre evaluation along the way. Another rapid stop, another new set of green-branded tyres.

10:28 Vergne is also on intermediates and only lapping in 1m44.2s.

10:30 Gutierrez's Sauber has been tidied up and is back on track.

10:31 Lack of Alonso and freezing weather means a reduced grandstand crowd today. Trackside spectator numbers are roughly "early morning Castle Combe" reckons our roving man.

10:31 Massa finds a bit more grip and gets the fastest time down to a 1m27.919s.

10:32 Bottas, who has yet to do a flying lap today, comes out to sample conditions too.

10:32 Just about to commence our AUTOSPORT Live Q&A with technical expert Craig Scarborough.

10:34 Van der Garde is also exploring track conditions.

10:34 That gives us seven cars on track despite the weather - rather better than we feared when looking at the forecast.

10:37 Van der Garde is on intermediates but still improving his pace, getting up to fifth.

10:37 A six-tenths improvement from Massa brings the benchmark time down to 1m27.351s.

10:38 Bottas is trying soft slicks but has yet to set a quick time.

10:40 How would having a pullrod front suspension affect tyre wear compared to pushrod?
Jim Phillips, Devon

@ScarbsF1: "It's the wishbones that affect tyre/suspension geometry and therefore tyre wear, so pushrod or pullrod makes no difference."

10:41 Hamilton goes back to the top with a 1m25.929s.

10:42 Bianchi does a 1m28.021s to go third on medium tyres.

10:43 Bianchi deposes Hamilton with a 1m25.732s, 0.047s quicker than the Mercedes.

10:44 Grosjean is seeing how the hard slicks behave in this weather. He does a 1m34.800s to go fifth.

10:45 Button tries the medium tyres now.

10:46 More technical wisdom from Craig Scarborough next...

10:47 "McLaren's decision to go for a higher nose on the front of the car and set up the geometry for a higher rollcentre... is this a purely aerodynamic decision based on trying to get the rear floor to work better or could it also be a mechanical decision to get the front tyres working harder for smoother drivers like Perez and Button?"
James Healey

@scarbsf1: "I suspect the primary reason will be aerodynamics. It's hard to make judgements on rollcentre position but any change in geometry from last year will be a secondary effect of the high nose."

10:48 Those mediums work well enough to get Button up to third on a 1m27.679s.

10:49 "What are the biggest new innovations you have seen in the 2013 cars and what is the purpose of the unsymmetrical bumps in the nose of the Lotus next to the step?"
Antti Lantto

@scarbsf1: "I haven't seen many new innovations this year, mainly just better interpretations of designs used in 2012. Probably, the slim sidepods of the Sauber stand out as the best new idea.

"The bumps are because of the front suspension rockers. As Lotus sometimes runs a roll damper, this needs to be above one rocker and below the other, hence the asymmetric bumps."

10:50 Button jumps to the top with a 1m25.313s on medium slicks.

10:51 Van der Garde does a 1m30.443s on soft slicks and takes fifth.

10:51 Having swapped his earlier intermediates for medium slicks, Vergne takes sixth on a 1m31.859s.

10:53 Now we're firmly in the realm of quick dry times as Hamilton laps in 1m23.282s.

10:55 Hamilton is 0.3s off that pace next time past. He is using mediums.

10:56 Besides the teams trying to get the maximum downforce out of their exhaust systems, what are they focusing on the most for performance gains? Is there another area where a lot of progress has been made?
Niels De Lathouwer
@scarbsf1: "I would guess the focus away from the rear end for the teams would be making the front wing work better with the airflow around the front wheels. That means that the wing endplates and brake ducts remain an area for development.

"I haven't seen a big step from the new teams, although Marussia now has KERS and Caterham has yet to introduce its new aero package. I fear they will still be fighting each other and not the midfield."

10:58 Latest jump in pace comes from Chilton, who laps in 1m33.120s on mediums.

10:58 Hamilton's lap times have now gone up to 1m27s.

10:59 Chilton finds another three seconds and does a 1m30.680s.

11:00 Webber, another man using mediums, gets Red Bull on the timesheet for the first time today with a 1m29.746s in fifth place.

11:03 A flurry of green across the timing screens as Webber, Gutierrez and Chilton all make improvements.

11:04 Vergne uses softs now and jumps to second on a 1m24.071s, 0.7s off Hamilton.

11:04 Moments later, Button (on mediums) snatches second away from Vergne with a 1m23.633s.

11:05 Vergne backs off on his next lap, then goes for it again but locks up into Turn 1.

11:06 Gutierrez finds another tenth but stays fifth.

11:07 "Where is the fuel tank and what does it look like?"
JJ75

@scarbsf1: "The fuel tank sits in between the driver and the engine in the middle of the car. This video from Sauber shows exactly what an F1 car looks like when cut in half."

11:08 That time around Gutierrez finds a second and does a 1m25.239s, but stays fifth.

11:08 Track is starting to get quieter now after that rush.

11:10 That means AUTOSPORT Live's Roving Trackside Reporter can put his gloves back on after some sterling tyre identification work.

11:11 Massa is now back in seventh despite being fastest not long ago. Using mediums again, the Ferrari does a 1m27.666s.

11:12 "Given #BOTTAS felt the biggest improvement on the Williams was rear grip, how much time do think Williams will lose when they revise their exhaust system?"
Christopher Elliott

@scarbsf1: "The removal of the small bit of bodywork around the exhaust that the FIA feels isn't within the regulations will only cost a tiny amount of performance. I doubt the drivers would be able to feel the difference."

11:12 Massa shaves another tenth off his time and that squeezes him ahead of Webber into sixth place.

11:14 "Both Lotus and Ferrari have spoken of how their Coanda exhausts cause a loss of engine power. Why is this the case and how do teams go about correcting it?"
Kem

@scarbsf1: "To make the Coanda exhaust set-up work, the tailpipe needs to be narrowed and other pipework bent into tighter shapes. This creates restrictions inside the exhaust that sap power from the engine.

"Teams will be looking at detail exhaust design and engine mapping to find more mid-range power to offset peak power losses."

11:15 A three-second jump by van der Garde takes the Caterham to sixth.

11:18 Van der Garde, Massa, Webber and Bottas are the men on track now, as Craig Scarborough cracks into some more of your questions.

11:20 "I have a question about the sensor grids used by the teams. How crucial is it to set these up precisely and how do they align the data with the CFD model?"
G Papp

@scarbsf1: "You are right, the probes need to be accurately aligned with the airflow to give accurate results

"This will be taken from CFD data and the probes will measure pressure and also temperature."

11:23 Amid the swirl of tyre changes and fast laps, we haven't given you a lap tally for a while.

11:24 It reads: Hamilton 41, Button 27, Vergne 34, Bianchi 23, Gutierrez 45, van der Garde 20, Massa 44, Webber 28, Chilton 20, Grosjean 18, Bottas 23.

11:27 Button is now out again on mediums lapping in 1m26s and 1m27s.

11:31 The rain has returned. It's light, says AUTOSPORT Live's Roving Trackside Reporter, but it's rain.

11:33 Webber and Chilton are on out-laps nevertheless

11:35 The Red Bull and Marussia simultaneously pit, but Webber goes out again to have another look.

11:37 Webber goes for a flying lap on intermediates. The rain is easing off now.

11:38 Webber clocks a 1m39.8s.

11:39 Massa is heading out again too.

11:40 As is van der Garde.

11:44 Massa gave the full wets a go but was soon back in the pits.

11:44 Gutierrez and van der Garde are on circuit now.

11:44 Craig Scarborough is about to answer a couple more of your technical questions.

11:45 "Which car do you think looks the most impressive in terms of both short and long runs so far in winter testing."
Nipam Shah

@scarbsf1: "I tend not to take much notice of testing times as most teams have yet to fit their definitive aero package. But it's clear that Lotus is up with the top three."

11:46 Red flag.

11:46 Van der Garde's Caterham has stopped near Campsa.

11:47 "What is your take on the Williams exhaust? Do you have any technical insight into why Williams believe it is legal, but the FIA believe it isn't?"
Matt Rowley, Lichfield

@scarbsf1: "It's clear to me the exhaust bodywork would be illegal. Williams's position is that it meets the wording of the published rules. But the FIA believes the design is outside of a clarification that was issued last year.

"Most likely, the team was testing the waters to see how far it could go under this clarification."

11:47 A big truck and a small truck are on scene with the stranded Caterham.

11:49 "Given the smaller turbo engines for next year, will exhaust blown diffusers and the Coanda effect still find use in the 2014 cars?"
Karthik Harinath

@scarbsf1: "The rules for 2014 demand the exhausts exit along the car's centreline. The current method of blowing the edge of the diffuser won't be possible.

"The outlets must also be above a certain height, so blowing the middle of the diffuser won't be possible either."

11:50 Caterham's covers are now on the car and it's about to be winched upwards.

11:51 So that's five stoppages overall, and two for Caterham, on the final morning.

11:53 Rescue Watch: a third car has just turned up, only to find the Caterham already loaded up and ready to move on. Even through the CCTV the disappointment is palpable.

11:53 Sure enough the marshals of the new arrival clamber back into the car, turn round and head back off.

11:54 There's been a lot of talk about tyres and degradation so far in pre-season, but Jenson Button thinks the new Pirellis are easier to understand and will offer a fair playing field. Read it here.

11:56 And while today's running has been truncated, yesterday afternoon several teams managed the first long runs of 2013. Romain Grosjean was the first to do a full-race simulation, and his pace and consistency didn't escape notice. Read what Nico Hulkenberg made of the Frenchman's stint here.

11:56 Green flag and we're underway, albeit with four minutes on the clock.

11:59 Jean-Eric Vergne is the first out of his pit box, but rather than join the circuit he pulls immediately to the right and stop just after the pitlane lights. Jules Bianchi sidles past and rejoins.

12:00 No-one else seems too fussed, unsurprisingly. We're into the final minute of the morning.

12:00 Jules Bianchi just missed out on coming round before the chequered flag, and a truncated final morning comes to a close.

12:01 Vergne incidentally was fine, just waiting. He's back in the Toro Rosso pits now.

12:03 Bianchi comes back round, and we're at lunch.

12:04 In a break between showers, and in between red flags, Lewis Hamilton edges out his 2012 McLaren team-mate Jenson Button to go fastest on the final morning.

12:06 AUTOSPORT Live is also off to find food, but we'll be back at 13.00 GMT. In the meantime you can read up on all the morning's action here.

13:00 Welcome back to a now sodden Barcelona. A rain shower (plus some hail) means that we have the prospect of a wet final afternoon to look forward to.

13:00 We are at least green again, although there's not exactly a rush to head out.

13:03 If you missed the morning's action, Lewis Hamilton made the most of a break between showers to set the pace for Mercedes, ahead of Jenson Button and Jean-Eric Vergne, who caused one of five red flags.

You can read our full report here.

13:07 And, in case you missed out, some of latest news from the paddock:

Jenson Button says F1 tyres easier to understand in 2013
Nico Hulkenberg impressed by Lotus's form
Webber backs evolutionary approach for Red Bull car design

13:08 We have our first car - Vergne, third fastest in the morning, heads out for Toro Rosso.

13:10 Asked whether the test would be ruined by rain yesterday evening, Vergne was confident there were still things Toro Rosso could learn:

"You can still get some stuff," he said." We have new tyres as well for the wet so we need to see how they are, and we need to see how the car performs in the wet as last year we had a good car in these conditions. So there is quite a lot we can do.

"It is of course [a disruption] though. You never have enough with just 12 days [of testing], so if you lose one day with the rain it’s big..."

13:12 Vergne heads in, but Gutierrez and Grosjean are now out. Gutierrez's first effort is a 1m50s.

13:15 Grosjean's first flyer is around one second faster than Gutierrez's effort. Full wets for the Frenchman.

13:19 And just the one lap too. He follows Gutierrez into the pits, and we're quiet once again.

13:22 Gutierrez, gearing up for his debut season in Formula 1, heads out again in the Sauber.

13:26 It's very wet out there though, and he's having to be very tentative through the long Turn 12 and the final section (which we can see via CCTV rather than our trackside reporter, who has wisely decided to find shelter).

13:27 @Marussia_F1Team: "It's been raining heavily during the lunch break so it's a very damp track we will rejoin but good for testing the wet tyres & also KERS."

13:33 Yesterday, as part of our Ask the Edd section, we had an excellent question from Paul Hensby, who was 'working'.

If you owned the '12th' team, which two drivers (one experienced, one rookie) would you have in and why?

We're opening the question up, and want your suggestions. The criteria is as Paul specified - they have to be current drivers, one has to have Formula 1 experience and one has to be a rookie. Oh, and budget is no issue (you can tell this is really hypothetical now). Edd Straw will be weighing in with his own pick later this afternoon.

Email us at live@autosport.com or tweet us using #autosportlive.

13:38 Gutierrez has company. The Mexican has done 12 laps already this afternoon, comfortably more than anyone else. Button, Vergne, van der Garde and Webber have all joined in quick succession.

13:39 Before @stevenenglish left AUTOSPORT Live to do... something... in Formula 1, he was obsessed with the "snazzy" Barcelona helicopter.

13:40 So especially for our former colleague, here it is.

13:40 An element of bias in this one, which suits us fine. The second pick in particular isn't easy to argue against:

@FakkiKovalainen: "I'd choose Heikki Kovalainen (duh) and Antonio Felix da Costa."

13:41 The worst part of that shot is that someone else is photographing it too, so @stevenenglish will think everyone loves the helicopter.

13:42 @stefan_f1: "Alonso (lots of xp, racecraft, talent, mentally and physically fit) & Bottas (looks promising)."

@buntjuh: "If I owned the 12th team, I would have Kamui Kobayashi and Robin Frijns as drivers."

13:43 Rain might have complicated how useful the afternoon will be for running, so Red Bull has switched to pitstops. Mark Webber heads in for his second straight practice run.

13:46 @Andygf1: "12th team Heikki Kovalainen and Danica Patrick!"

(Incidentally Danica finished 17th in the first 'Duel' qualifying race at Daytona. Read about it here.)

@AndyYoungF1: "My number one driver would be Kamui Kobayashi and my rookie would be Davide Valsecchi!"

And another for Valsecchi:

@StallionTom: "I'd risk it... Grosjean for number one and Valsecchi for number two."

13:46 We're red. First of the afternoon, sixth of the day.

13:47 It's Gutierrez who has gone off. His Sauber is beached down in the Turn 4 gravel.

13:50 Craig Scarborough was flooded with questions earlier today, and he's found the time to answer a few more. As we run those, keep your 'Ideal Team' selections coming in and we'll keep you updated with the latest from the track.

13:51 Which right now means kicking Recovery Watch into gear. There's a low loader and a plethora of marshals down by the Sauber, and they're getting ready to lift it on now.

13:53 @Christian_Rose1: "I'd choose Alonso and James Calado! Fernando's expertise, with James' natural talent would go well together."

@thesasgeek: "If I owned the 12th team I'd have @JensonButton and @thesasgeek (me!) as drivers. I'd love to drive an #F1 car #autosportlive #moneyNoObject"

We've spotted a flaw in our criteria...unfortunately recommending yourself isn't allowed, or there's a danger Edd Straw would recall his halcyon Ginetta days and put himself forward.

13:56 The loader is en route back to the pits. From the tyre marks it looks like Gutierrez stopped just short of making contact with the tyres.

13:59 One of our earlier questions for Craig Scarborough, which he has somehow (and very kindly) found the time to answer.

What is the advantage of having a narrow sidepod like Sauber's design?
Aditya, India

@ScarbsF1: "The first gain is that there is simply less sidepod to
obstruct the airflow and cause drag. But it also ensures the airflow passes over the exhaust outlets more effectively, to bend the exhaust flow down to blow on the diffuser."

14:00 The Sauber is back in the pitlane, Recovery Watch is taking a well-earned break and we're back underway.

14:00 Hamilton, Grosjean and Vergne head out immediately.

14:03 Which is slightly surprising given Hamilton earlier played down the worth of testing in the wet. Asked what he planned to do this afternoon, he said:

"Hopefully just taking the dog for a walk. I don't really like driving in the rain unless it's racing. Testing in the rain is a risk that there's sometimes no point taking."

14:04 Hamilton is back in quickly, but as he dives in Chilton, Button and Webber head the other way.

14:06 Some more suggestions for the ideal 12th team line-up:

@Paul11F1: "Answering my own question: Jaime Alguersuari & Antonio Felix da Costa!"

@notavailable9: "If I owned the 12th team, I would have Kamui Kobayashi and @lucasdigrassi as drivers!"

@Blacksimus30: "12th team drivers would be Heikki and Casey Stoner. Imagine that!!"

@f1zone: " If it's young talent, surely Antonio Felix da Costa and Robin Frijns."

14:08 @MercedesAMGF1: "Should we opt for a Curly Wurly, Fudge bar or Freddo Frog? There are no bad choices... :)

"Yes, we are proud to be asking the questions that really matter in F1 2013. Meanwhile @LewisHamilton returns to the track..."

That's not hard. Curly Wurly wins hands down.

14:09 Button puts in this afternoon's fastest time, a low 1m43s. Vergne is around two seconds slower, while Chilton and Massa are a few seconds further back.

14:10 Wets still very much the tyre of choice, even if it has stopped raining.

14:13 Vergne and Massa pit, but in Button, Bianchi, Webber and Chilton we still have four men out on track.

14:14 Another earlier question for technical guru Craig Scarborough:

Drivers have been complaining about the cold conditions causing heavy degradation of the tyres. But it's generally hot conditions that cause that problem. So why are the new tyres so sensitive to the cold?
Brendan, Hong Kong

@scarbsf1: “The problem is known as cold tear. The tyre is cold and hence harder than it should be, so the tyre will slide more and literally tears the tread surface away. This obviously wears the tyre more quickly.”

14:18 And a few more driver suggestions, which are growing more and more varied:

Marcos99: "I would do everything to bring back Michael Schumacher (to help building up the team). I would pick Simon Pagenaud as the other driver (more than promising performance in IndyCar so far).

Anders: "I would love to have Juan Pablo Montoya, because I loved the way he drove when he was active, although I guess he needs to shave off a few pounds. The rookie is tougher, but since I’m Norwegian, and we haven’t had any Norwegian F1-drivers, I would like to test out Pal Varhaug (drove with Romain Grosjean in GP2 in 2011)."

Hannah: "Mark Webber and Mitch Evans. Both seriously quick and already know each other well so would have a good team dynamic."

14:22 Anders's selection is all the excuse we need for a shot of Montoya's last grand prix win - Brazil 2005.

14:30 Button is on a pretty lengthy run now. His times are fluctuating though - a mid 1m41s was followed by a 1m44s and then a 1m40s. He's on intermediates.

14:32 Vergne is also on inters, while van der Garde - who has just come in - is on wets.

14:33 Another spot of pit stop practice for Webber. Rapid work and he's back out in the RB9.

14:37 After his afternoon off, Gutierrez is back out in the Sauber.

14:38 And while he circulates and Webber keeps Red Bull busy, we'll bash through the final four questions of the day for technical guru Craig Scarborough, starting with Darren Adamantiere.

What is the suspension travel difference between front and rear?

@scarbsf1: "It’s more than twice the difference at the rear, about 30mm front and 75mm rear."

14:39 Felipe Massa heads out for Ferrari.

14:40 How do you create your detailed technical drawings? None of the tracing software I know can do it so detailed, so I guess you do it by hand?
Ivan

@scarbsf1: “I use adobe illustrator and a mouse. My pictures are so detailed as I draw 'freehand' and don't trace. A lot of the detail in the drawing doesn't exist on the source picture. A full car takes me about eight hours and the same again to add colour and logos etc!”

14:42 Smoother stop by the Red Bull men this time around. Timing Live duties and photography attempts is proving pitiful, but we're determined to get at least one snap of a practice stop.

14:43 Until then, here's our penultimate question for Scarbs:

Does the size of the air intake affect the power of the engine. I have seen some teams using larger air intakes?
Sachni Francis

@scarbsf1: “I don't think the intake sizes vary as much as their shape suggests. At higher speeds there’s more air going in than the engine needs, so some air will even spill back out of the inlet.”

14:46 Sadly, this wasn't AUTOSPORT Live's own effort (which is too terrible to post). Luckily, XPB was on the scene.

14:48 Button, Vergne, Gutierrez, Massa and Chilton (plus of course Webber when he's not stopping) all out on track.

14:50 And our final question from Craig Scarborough, to whom we owe a massive thanks.

What is the data gained from the flow visualisation paint on the car?
Aditya, India

@scarbsf1: “The trails made show where airflow is passing over the bodywork. It will show if the flow is going in the direction it’s expected to and if it’s separating from the bodywork. Some teams might be shocked with their flow vis results this week."

14:52 Sub four seconds for Red Bull that time round, but we've lost count of how many that is now.

14:56 After speaking to reporters at lunch, AUTOSPORT's Edd Straw among them, Valterri Bottas has handed over to Pastor Maldonado for the afternoon.

14:58 Bottas, incidentally, completed 23 laps this morning without setting a single timed lap. We call that a lot of pitstop practice.

15:02 While Craig Scarborough took the time to answer a final few questions we had to stop with the 'Ideal Team' nomination. They haven't stopped coming in though, so with our excuses, here's a selection of other suggestions:

@EmilyKGalloway: "Heikki Kovalainen and Oliver Turvey :) Heikki shouldn't be off of the grid!"

@CharlesWessman: "I would choose Michael Schumacher and Alx Danielsson. You can´t argue with seven world titles..."

@sergiojavier8: "I would go for Alguersuari (Technically) and I would risk it and bring up Carlos Sainz Jr. (He's shown great speed lately)."

@DPustjens: "I would love to see Robert Kubica in my team when he would recover + Robin Frijns, because he is the most promising driver!"

@Sant_Alonso: " I would choose Schumacher (Lots of experience and he still is fast and clever) and Jules Bianchi, lots of potential and quick."

15:04 So far Maldonado is mirroring Bottas - he's now up to five laps but hasn't come round to start a flying lap.

15:07 Vergne, Chilton and Button pit in quick succession, leaving Bianchi and Massa as the only two runners.

15:11 Morning pacesetter Lewis Hamilton heads out for Mercedes, coming round just as Bianchi reaches the Force India pitbox.

15:14 @n8onyT@ "12th team, Davide Valsecchi and Kamui Kobayashi..."

@richierandle: "As a proud Midlander, I'd have no hesitation in employing the services of James Calado and Stefan Hodgetts."

15:18 Romain Grosjean, who yesterday afternoon completed the first full-race simulation of 2013, heads out to join Hamilton, Webber and Maldonado.

15:19 Hamilton was talking to reporters at lunchtime today, and was keen to stress that his F1 rivals' faith in Mercedes was too generous. You can read the full story here.

15:22 Valtteri Bottas was also speaking to reporters. After 23 laps without setting a time, he declared himself happy to have improved his pitstop routine. Again, you can check it out here.

15:27 Yet more suggestions for the 12th team's line-up, and yet more variation. Interesting how many names have cropped up.

Barry McManus: "Alonso and Dario Franchitti."

Michael Rasmussen: "Jan and Kevin Magnussen. First father/son pairing since... the beginning of time."

Phil Waldron: "Juan Pablo Montoya (1999 - 2001 Vintage) for the experienced driver - because he kicked bottom when he was on it in both Champ Car and F1, but appeared more interested in McDonalds post that period.
Valentino Rossi - because we just need something like that - great attitude and entertaining interviews, nothing bland there."

And another for the seven-time MotoGP champion:

Andrew Twigg: "Hamilton and Rossi - now that's a team to shake things up!"

15:30 We have our second red flag of the afternoon, and it's for Mercedes.

15:31 Lewis Hamilton is stopped out between Turns 6 and 7.

15:31 He's on the outside of the track, just before the left-right approach to Campsa.

15:37 And as Recovery Watch kicks into gear (very quickly actually as the low loader is already on scene), it's the perfect chance for a few more 12th team suggestions.

@Lukstins88: "Alguersuari (should be on grid) and Calado (lots of potential)."
Brian Lelas: "Sebastien Loeb (give him the drive that Toro Rosso couldn't) and Antonio Felix da Costa. What an exciting pair!"

Martin Christensen: "I would definitely get Lewis Hamilton and Giorgio Pantano, two epic talents. Just one of them got a proper chance in F1, but the other deserves it."

David Tremayne: "My 12th team is simple - Tonio Liuzzi and James Calado." (The first certainly won't surprise those who know him!)

15:39 Hamilton's W04 has already been removed, and we should be back to green shortly. Just over 20 minutes of the final afternoon remaining.

15:41 We're back to green, and Jean-Eric Vergne is the first to take advantage.

15:50 We're into the final 10 minutes, so here's a final few suggestions for our 12 Team (credit again to Paul Hensby).

Will Crouch: "I think Loeb and Frijns would be interesting."

@asamulya: "I would take Sutil as the experienced driver and Brendon Hartley as rookie driver."

@Rachi16: "I would have Jacques Villeneuve and Jules Bianchi."

F1 editor Edd Straw will be profferring his own suggestions shortly.

15:56 To round off the 12th team driver line-up debate, our F1 editor Edd Straw (@eddstrawF1) gives his selection:

15:56 Another red flag interrupts Edd's point.

15:57 Bianchi has coasted to a halt near the pit exit.

15:57 That's a very convenient place for a lot of recovery vehicles to rapidly swarm onto the scene.

15:58 To swiftly finish Edd's veridct, he would have Sebastian Vettel for his experienced choice and Antonio Felix da Costa for his rookie.

15:58 But if he had to choose only between drivers currently available, it would be Timo Glock and da Costa.

15:59 No time for the session to restart, so this will mark the end of week two of pre-season F1 testing for 2013.

15:59 Hamilton comes away with the day's fastest time - a 1m23.282s.

16:00 Button is second, 0.351s adrift, and followed by Vergne, Bianchi, Gutierrez, van der Garde, Massa, Webber, Chilton and Grosjean.

16:00 The chequered flag comes out to formally bring the week to a close.

16:00 Both Williams drivers had some track time, but neither did any flying laps as they focused on pitstop practice.

16:01 AUTOSPORT Live will return when testing resumes on Thursday February 28, just under a week from now.

16:02 In the meantime, we'll have all the news from the paddock tonight, plus analysis features today and through the weekend.

16:02 Thanks for your company this week, see you again for the final pre-season run-in.