07:56 Good morning and welcome to a very big day of pre-season Formula 1 testing at Barcelona's Catalunya circuit.

07:57 No fog here this morning so there won't be any issues with our 9am local time start, unlike yesterday.

07:57 With just two days of running left before Melbourne, things are getting very serious.

07:57 Several teams are bringing substantial upgrades for today, most notably Red Bull and McLaren.

07:58 Mark Webber will be driving the latest Red Bull RB8 chassis to be finished, and it features several steps over the car run so far in testing.

07:58 Sebastian Vettel said yesterday there was no point trying to draw any conclusions about Red Bull's form until he tried the definitive car this weekend:

Vettel not judging RB8 until updates

07:59 There's a big crowd of photographers waiting outside the Red Bull garage to play 'spot the difference' and see if the car has any visual differences to yesterday.

08:00 Track temperature is already 12.2 degrees, and another sunny day is in prospect, with a top temperature of 15 degrees forecast for later.

08:00 Green flag and we're underway.

08:01 AUTOSPORT's Jamie O'Leary gets his first squint at the revised Red Bull as it pulls out of the garage and reports it looks identical on an initial glance.

08:02 We placed @NobleF1 down there as well, so we'll have more information soon when he gets back from the pitlane.

08:03 Already out on installation laps: Mark Webber's Red Bull, Ferrari's Felipe Massa, Caterham's Heikki Kovalainen, Force India's Paul di Resta, Sauber's Sergio Perez and Toro Rosso's Daniel Ricciardo.

08:03 Red Bull has its space age rear wing cover ready for when Webber returns. Could that be where the key updates are? Or is it a diversion?

08:03 Nico Rosberg makes his first appearance of the day for Mercedes.

08:04 The initial group of cars are now back in the pits for system checks after those installation laps.

08:06 Bruno Senna's Williams is out too.

08:07 Just waiting for Kimi Raikkonen in the Lotus and Jenson Button in the McLaren now.

08:08 There's been a change of plan at Caterham, where Kovalainen reclaims Saturday from Vitaly Petrov having missed his planned Thursday run due to food poisoning. Petrov will be back in the car tomorrow as scheduled.

08:09 @NobleF1 says there are major updates to Red Bull's RB8. More details soon.

08:09 Massa is the only man who went for two installation laps not one.

08:09 Quite a turnaround for the Ferrari man after being sacked yesterday then rehired... Or at least that was what a wild internet rumour suggested.

08:10 Twitter briefly went crazy yesterday evening with the 'news' that Ferrari had allegedly ditched Massa.

08:12 Which prompted this amusing Twitter dismissal from @InsideFerrari: "It's a shame Massa's been too busy to keep up to date [with the rumour], as he's been in the usual briefing with the engineers. Maybe the person writing this tale does not realise that Carnival ended some time ago..."

08:12 Raikkonen completes an installation lap in the Lotus.

08:13 It feels like so long since we saw him in the car, it's almost like a second comeback...

08:14 Raikkonen did the first two days of test one at Jerez before handing over to team-mate Romain Grosjean, then missed all of the second test at Barcelona last week due to Lotus' chassis drama. Which means his last appearance in the cockpit was way back on 8 February.

08:15 Already quite a few punters in the main grandstand. With the working week done, there should be a few people keen to check out the new cars pre-Melbourne.

08:15 Massa breaks the brief silence and heads back out.

08:15 #massanotsackedafterall, you might say.

08:16 Also, if Ferrari does decide not to renew Massa's contract at the end of 2012, that doesn't mean Twitter rumours were right last night, OK?

08:16 News story detailing Red Bull's major updates is imminent...

08:16 Massa is straight back in and switches the engine off. The periscope measuring device is attached, as is standard for Ferrari at this time of day.

08:18 Raikkonen's return to action keeps Lotus at the forefront today, not that it needed the Iceman to grab the headlines, as Grosjean has been fastest all week so far - snatching the top spot at the end yesterday:

Grosjean fastest again at Barcelona

08:18 But what was really encouraging for Lotus was a very strong and consistent race simulation:

Grosjean pleased with long-run pace

08:19 Does that mean Lotus will spring a surprise in Melbourne? Or will the shock come from yesterday's second-fastest team Toro Rosso? AUTOSPORT Plus subscribers to read our thoughts on the subject here:

Inside testing: Barcelona blog

08:20 Webber fights his way through the photographers to bring the revised RB8 back out on track, using medium tyres.

08:20 Perez makes his way out too.

08:22 Mediums on the Sauber too as it and Webber's Red Bull blast down the straight.

08:22 Great West Australian Ricciardo is next out, on mediums as well.

08:22 Webber logs the first flyer of the day, a 1m28.643s.

08:22 With the changes to its car seemingly so extensive, Red Bull will want maximum mileage today.

08:23 Down to a 1m26s for Webber next time, as Perez starts off with a 1m30s.

08:24 Full story on the revised Red Bull (and McLaren) now available:

Red Bull and McLaren reveal updates

08:25 Raikkonen is now back on track too.

08:26 Webber leads with a 1m26.268s, Perez is now on 1m28.044s, and Ricciardo has done a 1m29.169s.

08:26 Ricciardo leapfrogs Perez with a 1m27s.

08:26 Senna does a practice start on the way out of the pitlane, as Raikkonen comes back in without going for a flying lap.

08:27 But the Lotus goes straight back out again.

08:27 Senna is running hard tyres on the Williams.

08:30 Senna, Raikkonen and Webber all pit, and immediately Red Bull mechanics swarm around the RB8.

08:30 Ricciardo goes fastest with a 1m26.080s lap.

08:30 Rosberg is now out on softs.

08:31 Another view of the revised RB8 - more on our homepage and news story, and in the gallery later.

08:31 Kovalainen sets off again too.

08:33 Ricciardo improves to 1m25.164s, as Rosberg goes second on a 1m25.741s.

08:33 Rosberg improves, but Ricciardo still has the top time by 0.030s.

08:34 Kovalainen goes out and back in, still yet to set a time.

08:35 Kovalainen rejoins and has the track to himself as Rosberg comes in.

08:36 And as expected, Kovalainen pits and all is quiet for now.

08:38 Caterham is doing 15 minutes of pitstop practice, @MyCaterhamF1 reveals, so Kovalainen will be in and out a lot for a while.

08:38 Perez and Senna line up for practice starts.

08:44 Senna goes top with a 1m24.256s.

08:44 After two days at the bottom of the timesheets, Williams is fastest.

08:45 Senna trims his time to 1m24.058s, putting him a second clear of Ricciardo.

08:45 Perez has got his time down to 1m26.382s, but is the slowest of the five cars to have set times so far.

08:45 Di Resta and Force India are also doing pitstop practice, heading out then back in again.

08:46 Senna comes back in. But after almost a full day of pitstop practice for Williams yesterday, we're not expecting much of that from the team today.

08:47 Perez improves to a high 1m25s and jumps Webber in the times.

08:48 Jenson Button has now completed two systems check laps in the McLaren without going for a time so far.

08:49 Rosberg goes second for Mercedes on a 1m25.144s.

08:50 Webber is now back out, and you can see more of the revised Red Bull RB8 on autosport.com now too:

Barcelona testing gallery

08:50 Webber is again running on medium tyres.

08:52 Webber straight to the top with 1m23.577s.

08:53 First lap in 1m23s of the day and it only took 51 minutes.

08:53 Massa now joins the party and deposes Webber with a 1m23.149s.

08:54 Frantic stuff this morning.

08:55 While Webber used medium tyres for his run, Massa is on softs.

08:58 Massa and Webber pit, and there's a moment of quiet on track before di Resta heads out, probably for another practice pitstop.

09:01 Our special guest on AUTOSPORT Live today will be Mercedes motorsport chief Norbert Haug.

09:02 He will be joining us this afternoon, so email live@autosport.com with anything you want to ask Norbert about testing, Mercedes, its drivers, its hopes or any other topic, now's your chance.

09:03 With just over an hour gone, Massa is quickest on a 1m23.149s, 0.428s ahead of Webber, with Senna third, Rosberg fourth, then Ricciardo and Perez.

09:03 No one else has set a time yet, but everyone has appeared for at least an installation lap.

09:04 And although Kovalainen and di Resta haven't done any flying laps, they've done so much pitstop practice they've already logged 14 and 13 laps respectively.

09:04 Di Resta stays out this time so might be going for his first flying lap of the day.

09:04 Massa is back on track for Ferrari too.

09:05 Di Resta resists the temptation to actually set a time and pits.

09:06 Massa is doing another soft tyre run.

09:07 The lap that put Webber fastest for a while and now places him second was set on lap one of a four-lap stint on medium tyres - which then tailed off from 1m23s into 1m24s and 1m25s.

09:08 Massa did his 1m23.1s on lap one of a run on softs, backed right off for a lap, and then delivered another 1m23.1s. Let's see what he can do this time.

09:08 The Ferrari improves again, edging further ahead with a 1m23.009s.

09:08 Button is out too, will McLaren finally complete a flying lap?

09:09 Button is running medium tyres, Rosberg is on softs again.

09:09 Like his last stint, Massa has backed right off after his quick lap.

09:10 Button sets a tentative first time in 1m28.605s.

09:11 Rosberg does a personal best of 1m24.353s in fourth, but is not matching the soft-shod Ferrari.

09:11 Yesterday there were some question marks over soft-tyre degredation for Mercedes:

Schumacher: Degradation needs work

09:12 Massa comes without going for a second flyer this time.

09:12 Button improves to fifth place.

09:12 Perez comes out on medium tyres.

09:13 Kovalainen stays out to start a flying lap after a long spell of pitstop practice for Caterham.

09:15 Soft tyres for Kovalainen.

09:15 Ricciardo heads out.

09:16 In three laps, Rosberg lost a second in pace on the soft tyre.

09:17 Ricciardo is out again on medium tyres.

09:17 Perez cruises down the straight, while Button comes in.

09:18 Kovalainen has started out with consistent 1m29s laps on soft tyres.

09:18 Busy on track, with Senna, Rosberg, Ricciardo, Perez and Kovalainen in action.

09:20 Senna is running hard tyres on the Williams this time.

09:21 Rosberg's run on soft tyres has seen a big drop-off in pace over just seven laps. This is how the times have unfolded: 1m24.3s, 1m25.0s, 1m25.3s, 1m25.5s, 1m26.0s, 1m26.7s, 1m27.0s.

09:21 Senna goes second on a 1m23.490s.

09:21 Looks on closer inspection like a set of unmarked Pirellis, which from a distance and at speed are quite easy to mistake for hards.

09:26 Di Resta is now the only man on track - and still to set a flying lap despite doing 16 laps of pitstop practice.

09:26 This time di Resta does go for a lap, and he jumps straight to fourth with a 1m24.350s on hard tyres.

09:29 By the look of the swarm of photographers gathering around the Red Bull pit, Webber is about to head out again.

09:29 The Renault engine fires into life.

09:30 Mediums on the Red Bull as it emerges from the garage.

09:31 And here's a picture showing how quickly and efficiently Red Bull will hide the car's secrets when it pits again at the end of this run.

09:32 Massa goes quicker again on soft tyres as he sets a 1m22.984s on his latest soft tyre run.

09:33 Perez does a personal best of 1m25.270s on soft tyres but is still only eighth fastest.

09:33 Massa now slows down again and goes over the line doing a constant speed test.

09:34 Or maybe he's cruising because he's reading the Jobs section of the newspaper?

09:34 (If you missed it last night, there was a wild Twitter rumour that Massa had been dropped by Ferrari with immediate effect. Don't worry, he hasn't)

09:35 Kovalainen does his best time of the day but it doesn't lift him above ninth.

09:35 Senna is out again on what looks like medium tyres.

09:36 Perez cruises past on a constant speed test.

09:36 Massa has now pitted, so he just did that one 1m22.984s flying lap on softs then the slow aero tests.

09:37 It seems Senna might have cut the chicane on his best lap, as his second sector is impossibly fast.

09:37 It's still on the screens, but we're not sure it's going to stay there.

09:38 According to the data, Senna managed to outpace everyone else by three seconds in sector two on the way to second place. That's a pretty good sector...

09:38 Ricciardo goes out.

09:40 Ricciardo does a new personal best of 1m24.145s on medium tyres.

09:40 That puts the 'Sandgroper' fourth.

09:41 (AUTOSPORT's Andrew van Leeuwen was providing what he described as 'useless Aussie trivia' earlier, including that nickname for Perth natives like Ricciardo)

09:42 Kovalainen pits after a hard tyre run mostly in 1m28s.

09:45 Tane Vilhunen asked us why Raikkonen's Lotus has only done 3 laps this morning. Well here's the answer... @Lotus_F1Team says: "All calm in the @Lotus_F1Team garage. Kimi was not quite happy with the steering so we're investigating accordingly #F1 #Raikkonen"

09:47 Massa joins Ricciardo on track.

09:48 Remember you can email live@autosport.com with any questions you have for our expert team, and to put questions to Mercedes motorsport boss Norbert Haug, who joins us on AUTOSPORT Live just after lunch.

09:48 Button and Kovalainen are also out now, as Ricciardo does a practice pitstop.

09:49 The Toro Rosso had done a six lap stint on medium tyres, starting in low 1m24s and going up to high 1m25s.

09:49 Kovalainen is on softs, and jumps to fourth on a 1m23.947s.

09:50 Now Massa is on hard tyres, and goes quicker yet again with a 1m22.896s.

09:50 Massa pits straight after that time.

09:51 Senna is on hards, and improves his time to 1m23.244s - this time without cutting a chicane as far as we can tell. If he did last time, who knows...

09:53 Button improves to 1m23.409s on soft tyres.

09:54 That puts the McLaren third ahead of Webber.

09:54 Perez is running on unmarked mystery tyres, while Kovalainen and di Resta have come into the pits.

09:54 Steering problems hopefully resolved, Raikkonen is back out on track and possibly about to do his first flying lap in an F1 car for 25 days.

09:55 Webber improves to 1m23.347s and takes third back from Button.

09:55 With this being the last day in the car before Melbourne for quite a few drivers, we could see quite a few race simulations this afternoon.

09:56 Senna comes in. That run on hard tyres was a slow 1m28s then a much quicker 1m23.244s.

09:56 Raikkonen is running medium tyres on the Lotus.

09:57 First lap for Raikkonen is just a 1m30.208s. But he's been out of it for a while and has just had steering attention, so give him a second.

09:59 Raikkonen improves a little to 1m28.365s.

09:59 Massa is back out.

10:00 Massa is now on super softs and he uses them to go faster still, lapping in 1m22.413s.

10:00 The Ferrari is now 0.8s clear of the rest of the field.

10:01 Rosberg is out on soft tyres again.

10:03 Rosberg does a new personal best of 1m24.228s in seventh place.

10:03 Massa pits after that single flying lap on super soft tyres.

10:04 Rosberg's tyres hold up OK for now as he follows his 1m24.2s with a 1m24.3s.

10:04 GP2 driver Marcus Ericsson is hanging around outside the Toro Rosso garage.

10:05 @NobleF1 reports that Lotus is running new front and rear wings and new bargeboards today.

10:05 Rosberg's pace now up to 1m25.0s.

10:05 Ricciardo is out on medium tyres.

10:06 Ricciardo improves his pace with a 1m23.777s on medium tyres in fifth place.

10:07 Mercedes is not running any new parts today, but did have a new rear wing yesterday.

10:08 Rosberg's pace on this soft tyre run has faded by a second across three laps.

10:08 We're expecting to see Lotus running a new engine cover tomorrow.

10:08 Rosberg now backs off to a 1m27.525s and didn't seem to be on full throttle over the line.

10:09 Raikkonen isn't up to speed yet, and @Lotus_F1Team provides more information: "A couple more laps for the Iceman as he assesses the steering. We're working on getting everything just as Kimi wants it."

10:10 Rosberg back up to speed now with a 1m25.9s, which fits the pattern of Mercedes tyre degradation seen this week.

10:13 Rosberg lifts off again as he crosses the line with a 1m26s.

10:15 We reckon he'll pit now... and he does.

10:15 We're expecting a lot of soft tyre runs from Mercedes today as it tries to improve its car's relationship with them.

10:15 Ricciardo is on his lonesome out there, seven laps into a medium tyre run.

10:16 Track temperature is now up to 26.1 degrees, and the ambient temperature is nearly at today's predicted peak of 15.

10:19 A recap, while it's quiet...

10:19 Massa fastest on 1m22.413s following some qualifying style runs, with Senna, Webber, Button, Ricciardo, Kovalainen, Rosberg, di Resta, Perez and Raikkonen following.

10:20 Ricciardo now pits and shuts the car down, so it's proper quiet.

10:20 The Toro Rosso has the day's highest lap count so far, with 38, while Kovalainen, Rosberg, di Resta and Perez have also all done 30 or more.

10:20 Just seven for Raikkonen, who has needed some steering adjustments on his Lotus.

10:21 We haven't seen a single red flag yet this moring, in contract to yesterday - though right now with no cars on track and a hush descending over Barcelona it feels like a red flag period.

10:21 We're still waiting for news on whether HRT will be able to make it on track for the final day of testing tomorrow. A decision is expected later this morning.

10:22 Even the pitlane is deserted at present.

10:23 We're just above the Red Bull and Toro Rosso garages, so we had a great view of the excitement this morning as everyone hurried to get a look at the revised Red Bull.

10:23 You can examine it yourself in our testing gallery.

10:23 Some noise, and Senna sets off.

10:24 Senna is on soft tyres.

10:25 More news from @Lotus_F1Team: "Just changing the steering column. Kimi wasn't happy with how it felt, the team are working flat out to get him back on track"

10:26 Webber is out of the car and running through the paddock. Quite possibly to the toilet.

10:29 While Senna has the track to himself, we learn from AUTOSPORT's Andrew van Leeuwen that being from Canberra makes Webber a Territorian. Which you could also apply to those from Darwin.

10:30 Senna pits, and the track is silent beyond the noise of Aussie trivia lessons in the media centre.

10:32 As some of the Aussie trivia is probably borderline dodgy for a family readership, it's fortunate that di Resta brings the Force India back out on track.

10:35 Di Resta jumps to second on a 1m23.206s using medium tyres.

10:37 That was a quick sprint from the Force India, which now pits.

10:38 Leaving the AUTOSPORT Live team learning from @avlmelbourne that Mark Webber used to be a ball boy for the Canberra Raiders Rugby League team.

10:39 We're also already gearing ourselves up for 'lunch watch' today, after missing out on both food and food spying yesterday because it was all too busy.

10:39 There's a faint sound of an engine somewhere own the pitlane.

10:39 Looks like Rosberg's Mercedes coming out.

10:40 Massa is coming out too.

10:41 Rosberg is in soft tyres again as Mercedes tries to get to the bottom of why the W03 is muching through them so quickly.

10:42 Mercedes motorsport chief Norbert Haug joins us just after lunch, keep emailing your questions for him to live@autosport.com.

10:42 Rosberg jumps to second on a 1m23.040s.

10:42 That's 0.6s off Massa at present.

10:42 Massa is lapping in low 1m23s on mediums now.

10:43 Di Resta and Senna are back on the circuit too - so that's all of the current top four.

10:43 Di Resta is running medium tyres on the Force India.

10:44 Williams is running a different nose today to yesterday, but it's the same update used on Thursday, the team just reverted back to an older spec yesterday when focusing on pitstop practice.

10:44 We've squinted a little harder, and di Resta is on softs, not mediums.

10:45 Senna is using super softs on his Williams, and Kovalainen is now out with softs on his Caterham too.

10:46 Improvements straightaway - Senna does a 1m22.480s and di Resta a 1m22.805s.

10:46 That cements Senna's second place and brings him to within 0.067s of pacesetter Massa, and moves di Resta up to third, 0.392s off the Ferrari.

10:46 Kovalainen improves on his super softs too, doing a 1m23.779s in eighth place.

10:47 While Webber tries out the revised Red Bull, Sebastian Vettel is milling around in the pitlane, and now takes up a seat on the pit wall.

10:47 Adam Falconer writes in that Webber is actually from Queanbeyan, which in New South Wales, albeit right next to the A CT. @avlmelbourne response to that is: "I know. He's from across the border. But he's a Canberra boy... just ask him!" We suspect we're wandering into to some localised border disputes here...

10:48 AUTOSPORT's Jamie O'Leary reports that Vettel's footwear is brown and somewhere between trainers and shoes.

10:49 Senna and di Resta seem to have been on qualifying simulations, as they pitted immediately after their rapid laps.

10:49 Rosberg's pace on softs has dropped off by two seconds over four laps.

10:49 Vettel has now wandered down to hang out at Toro Rosso, perhaps reminiscing about Monza 2008.

10:51 Webber fires up the Red Bull and prepares to go out while his team-mate chats.

10:51 Kovalainen just quickly popped out and back in.

10:51 Massa now also leaves the pits.

10:52 Webber is using hard tyres this time.

10:54 Ricciardo sets out with soft tyres on the Toro Rosso.

10:56 Webber's pace on hard tyres starts out in mid 1m24s.

10:57 Ricciardo improves to 1m22.768s and third quickest, doing the fastest first sector of anyone so far today.

10:59 The Toro Rosso is 0.355s down on Massa around the lap, and then follows that 1m22.7s with a 1m22.9s.

10:59 Ricciardo is the busiest man of the day right now with 41 laps, while Rosberg has done 40 and di Resta 39.

10:59 The Australian contingent pit as Webber and Ricciardo both come in, while Perez, Kovalainen, di Resta and Senna are out.

11:00 Medium tyres for Perez's Sauber.

11:00 We're an hour away from the penultimate lunchbreak of the F1 2012 testing season and it's still Massa fastest, but now by just 0.067s over Senna, with Ricciardo, di Resta, Rosberg, Webber and Button all within 0.9s. Kovalainen and Perez are next, and Raikkonen has only done a few laps while steering issues are attended to.

11:01 Perez sets a new benchmark in sector one.

11:01 Kovalainen does a personal best on super softs and moves up to fifth place.

11:01 Senna has super softs on too and looks like he's doing another qualifying simulation.

11:02 There's a lot of commotion at Ferrari - seems Vettel was spotted chatting there with Alonso. Let the conspiracy theories begin...

11:02 Di Resta brings the Force India back in. The Scot didn't go for a quick lap on that outing.

11:03 Just one flyer for Kovalainen on those super softs and he's back too.

11:04 Perez improves to 1m24.090s after three laps on medium tyres.

11:05 Bit of debate between AUTOSPORT's source of Aussie trivia @avlmelbourne and the AUTOSPORT Live readership over Mark Webber's origins. We reckon this video settles it.

11:06 Breaking news from @NobleF1: HRT will not make it to Barcelona for tomorrow's test. The team is aiming for a filming day on Monday instead. Full story soon...

11:07 Ricciardo in and Massa out.

11:07 That's the Toro Rosso pitting and the Ferrari leaving the garage, not another Twitter driver rumour.

11:07 Perez heads back out too.

11:08 Massa is running medium tyres on the Ferrari.

11:11 The Ferrari's pace is a second off its best of the day.

11:12 Di Resta is going back out on super softs. Expect a race simulation from Force India after lunch.

11:12 Speaking of lunch, people seem to be gathering around the table in the media centre, suggesting sandwiches may be imminent.

11:12 Perez improves to fourth with a 1m22.771s on soft tyres.

11:13 That was a qualifying simulation from the Sauber, which then heads back in.

11:13 Di Resta goes second fastest on a 1m22.446s with super softs.

11:13 That lap slotted him in 0.033s off Massa and 0.034s ahead of Senna. Neat.

11:14 Super softs also take Kovalainen up the order again as he does a 1m22.630s to go fourth quickest - only 0.217s off the pace.

11:14 That is very, very encouraging pace for Caterham.

11:14 Definite qualifying-style run for di Resta there, as he's already back in the pits. Expect the same from Kovalainen.

11:15 Massa now does a slow constant speed run in the Ferrari, lapping 21s off the time that currently puts him on top.

11:17 Rosberg started this run on soft tyres with a big lock-up into Turn 1, then did a 1m23s on his first proper lap.

11:17 Rosberg and Massa both pit, so it's just Ricciardo on track.

11:18 The Ferrari comes back out, and Ricciardo has to pass it at the start of a run on super softs.

11:18 But the Toro Rosso is still within 0.1s of the benchmark sector one time.

11:19 Ricciardo goes to the top with a 1m22.155s for Toro Rosso.

11:20 Looks like getting past the Ferrari (which came straight back in) didn't slow him.

11:23 Perez now flies to the top with a 1m22.094s on another qualifying simulation on super softs.

11:24 That was another single-lap run for the Sauber.

11:25 Quick tyre correction: we thought Perez was on super softs, but AUTOSPORT's Jamie O'Leary squinted again and they were softs - so the new top time wasn't on the absolute softest rubber.

11:26 Today's second media centre tour is underway. Wonder where seeing us in action ranks on the guests' list of highlights of their trip to F1 testing.

11:26 Rosberg goes back out on softs again. Who wants to put some cash on him doing a 1m23s then quickly tailing off?

11:27 Ricciardo is back out, moments after being knocked off the top spot by Perez by 0.061s. Will he try and claim it back?

11:28 We didn't actually bet any real money on Rosberg doing a 1m23s, and that was just as well because he actually did a very slow lap.

11:28 Super softs again for Ricciardo, and medium tyres on Massa's Ferrari.

11:29 Now Rosberg does the 1m23s we were expecting.

11:29 Webber pits after doing three laps on hard tyres in mid 1m23s and mid 1m24s.

11:29 Perez is going for another run on super softs.

11:30 Ricciardo does another 1m22.1s but can't beat Perez's time.

11:31 "Brace yourselves Raikkonen fans" warns @Lotus_F1Team

11:31 And sure enough, Raikkonen is back out after his change of steering column.

11:31 Perez's pace on super softs is six tenths down on what he did on softs.

11:31 Raikkonen's Lotus is running medium tyres.

11:31 Ricciardo comes in after that super soft run.

11:32 Some of you have been asking whether HRT is going to run its new car over the weekend. Well @nobleF1 has been over to see them in the paddock and it appears not... Here's the story.

11:33 Raikkonen improves on that second lap and does a 1m26.773s on medium tyres, but is still slowest.

11:35 Raikkonen now has the track to himself.

11:36 And at the top of the timing screens we have a second-year driver and a rookie (ish), while two ex-world champions bring up the rear.

11:36 But that is the thing with having six world champions in the field - they're going to get everywhere.

11:37 Lots of readers are emailing live@autosport.com asking if we know what's going on with McLaren, as Button has completed only 17 laps so far. We have nothing to report right now as there's no information coming out of the team. Yesterday Lewis Hamilton was similarly absent at times, and said at the end of the day that it wasn't car problems as such causing the delays, just that making changes was taking a lot of time.

11:38 It's cooling down at Catalunya - the track temperature was above 30 degrees an hour ago and it's now 27.8, and you can feel the ambient temperature going down too as cloud cover comes over.

11:38 Still just Raikkonen on the circuit, lapping in 1m28s.

11:38 Now Raikkonen pits.

11:39 So Lotus's "brace yourself" referred just to the excitement of seeing Raikkonen drive a car around again, rather than being a promise of imminent amazing pace.

11:40 Just 20 minutes until lunch now so another flurry of 'pole shots' from people doing qualifying simulations would do nicely.

11:41 But right now it's all quiet here.

11:41 Not for long, here come Perez on super softs and Rosberg probably on softs.

11:44 Softs for Rosberg indeed, and a new personal best of 1m22.932s.

11:45 Perez comes back in without setting a time.

11:45 Webber is on the track again too.

11:48 A quick flyer on softs for Webber takes the Red Bull to seventh on a 1m22.662s. And then he pits.

11:49 Rosberg is experiencing another huge drop-off in times in the Mercedes.

11:49 The Mercedes has gone from 1m22.9s to 1m25.4s in four laps.

11:50 It's hard to make definitive judgements about performance and trends when cars are all running different fuel loads and programmes, but time and time again over the last few days, Mercedes has come out on soft tyres, set a good time, then plunged in pace over the rest of the stint.

11:50 The car seems to use the best of the softs very quickly, then stabilise around the 1m25s bracket.

11:50 Webber sets off again.

11:51 Or maybe not. The Red Bull emerged but then the engine was shut off.

11:51 Now it's fired back up...

11:51 We'll wait until the car actually passes us.

11:51 Medium tyres on Massa's Ferrari for this run.

11:51 Webber does eventually set off, and is running the unmarked Pirellis that keep confusing us.

11:52 Actually, in fairness, the marked tyres have manage to confuse us a few times too...

11:54 A personal best sector one time from Webber.

11:55 But the Red Bull doesn't improve on its 1m22.662s best from a few minutes ago.

11:56 Yesterday Grosjean was the only driver to do a 1m22s, and that didn't happen until the day's closing minutes. Today, eight drivers are already in that bracket.

11:56 Lots of low fuel runs on the softer compounds this morning.

11:56 And the cars that most expect to set the pace in Melbourne - Red Bull and McLaren - are playing it cool back in seventh and ninth.

11:57 Webber started his run with a 1m22.7s, then backed right off to a 1m33s, and now we're waiting to see if he'll put in another flyer.

11:58 No late-morning surge from Massa, who is doing a constant speed run.

11:58 Raikkonen pops back out as the clock ticks down towards the break.

12:00 Doesn't look like we're going to see anything startling in these last few moments.

12:01 The chequered flag is out for the lunchbreak.

12:01 Raikkonen does a small improvement on mediums but stays last.

12:01 Massa, Rosberg and Webber will now end their runs too and head in.

12:03 We'll be back after the lunchbreak with Mercedes motorsport chief Norbert Haug answering your questions. See you then.

13:00 Welcome back to AUTOSPORT Live for the penultimate afternoon of pre-season running at Catalunya.

13:00 We're about to be joined by Mercedes' Norbert Haug, who will be answering your questions, but we'll make sure to keep you up to speed with all the on-track action too.

13:02 Green flag, and di Resta and Senna get the afternoon underway.

13:03 Bit of a pause before then in which we heard engines running but saw no cars...

13:03 It's probably tempting fate to say that we got through the whole morning with no red flags...

13:03 Morning pacesetter Perez brings the Sauber out.

13:04 If you missed it, the theme of the morning session was qualifying-style runs on soft and super soft tyres, and we saw plenty of changes at the top - mostly between likely upper midfield teams.

13:04 Rosberg and Ricciardo set off as well.

13:05 All eyes were on Red Bull as it introduced a substantially revised version of the RB8. More details here:

Red Bull reveals updated RB8

13:06 And bad news for all the HRT fans who were thinking "this will be the year when we get some pre-season testing at last"... it won't be... Try again in 2013.

HRT fails to make final test day with new car

13:07 Two drivers in obvious trouble this morning: Button lost running with a hydraulic problem on the McLaren, and Raikkonen spent a long time in the Lotus garage while his steering was changed.

13:07 Okay Norbert is with us now and is ready to answer your questions.

13:07 The first one is from Davor Smolic who asks: What can a Mercedes fan expect from this season? Where do you stand in the pecking order?

13:07 Perez is on super softs, but is cycling back through the pitlane so won't be going for a time.

13:08 Of that initial flurry of cars, only the Force India stayed out for a flying lap.

13:08 Norbert says: Only Melbourne will show. I am afraid everybody has to wait another two weeks.

13:08 Senna now comes around again too, on soft tyres.

13:09 Uday Motwain asks: With this year’s car, are you expecting Michael and Nico to target podiums and possible wins?

13:10 Norbert: "Not only our much-appreciated Mercedes fans, but all of the followers of F1. We definitely want to make a step forward. We have been fourth in the past two seasons which means that you normally have six cars ahead of us. To be in that group on a regular basis has to be our target."

13:10 While Norbert was answering that, his man Rosberg came in and back out again.

13:10 And now looks like he's going for a flying lap.

13:10 Hassan Hassan asks: Do you believe Schumacher is still capable of winning the championship?

13:11 Norbert answers: "Yes. If we give him a car that is capable of winning races and championships, then he can do it and Nico can do it too!"

13:11 Gary Tan asks: During pre-season testing, how do you decide on a test programme for drivers? Do you flip a coin to see who has the car on which days?

13:12 Norbert says: "There is no need to flip a coin. One driver drives one day, the other driver the next. There are many ways to decide - like the guy who did day one last year does day two this year."

13:13 Senna and di Resta are doing similar mid-1m30s laps on soft tyres. Big fuel loads, most likely.

13:13 Callum Bailey asks: Are you disappointed with the first few years of performance with Mercedes GP after taking over a title-winning team?

13:13 Norbert's man Rosberg also out on softs now.

13:14 Norbert answers: "No. Disappointment does not help. We all knew that it would take time to be in the order of the top three teams on a regular basis."

13:14 Alfonsas Navickas asks: Was Mercedes parting with McLaren as its 'works’ team a mistake, after so many years of success together? Why sacrifice that to start again from scratch, especially in an era when the manufacturers teams seem to be a thing of the past?

13:15 Norbert: "McLaren wanted to enter the market of sportscars, which we respected. We still have a great partnership and a fantastic working relationship with McLaren, and together we are one of the most successful teams for the past one-and-a-half decades."

13:16 We're comparing the Williams and Force India as they may well be on parallel race simulations.

13:16 Di Resta looking about half a second quicker than Senna on most laps so far.

13:16 Button comes back out in the repaired McLaren.

13:16 Andreas Kirsch asks: The W02 had a short wheelbase and one of the worst tyre wear rates of all the teams. Have you solved this problem with the W03?

13:17 Norbert: "Yes, we think we are heading in the right direction."

13:17 Button only did 17 laps this morning before a hydraulic problem needed attention.

13:17 David Surgenor asks: According to your drivers it seems that the new Mercedes package is continuing to have difficulties with tyre degradation. Is this due to aero issues caused by Michael Schumacher’s preference for extreme front-end grip?

13:18 Norbert says: "Every team can improve in every area, but I cannot see specific issues on the tyre front for us."

13:18 Rozman Zoli asks: Is the tyre wear issue that even Michael Schumacher has confirmed exists, something you can fix, or will it be a season-long issue like last year’s cooling problems?

13:19 Norbert says: "Same as the previous answer!"

13:19 Raikkonen and Ricciardo are now out.

13:19 Mads Breyen asks: Does Mercedes have a timeframe for success with your works team, have you set a specific goal for this year and the following years, and what will you do to achieve them? If you do not reach those goals is there a chance you will pull the plug on the team?

13:20 Norbert responds: "First of all a quick message for [Mercedes press officer] Bradley Lord - are you online or just relaxing? In answer to that question, we want to improve step by step and like every team we have to accept that this takes time. I am absolutely convinced that we will reach our targets in the future, like we reached them in the past."

13:20 We can't tell if Button is on hard tyres or the could-be-anything unmarked Pirellis.

13:21 Same with Ricciardo, we're afraid.

13:21 Dennis from Slovenia asks: How much would you pay Adrian Newey to come work for Mercedes F1 Team?

13:21 Norbert says: "Adrian is still a good friend, and has been since our McLaren-Mercedes days. I have a great amount of respect both for his strengths as a designer, and as a human being. But he is in the Red Bull team and we are in the Silver Arrows Mercedes team. We both respect each other and Adrian certainly knows that our target is to improve and create interesting races at the top of the field. Hopefully, sooner rather than later."

13:22 Raikkonen improves his pace slightly.

13:22 Running on medium tyres, the Lotus does a 1m25.379s.

13:22 Mallesh Magdum asks: Considering the fact that almost every component on an F1 car is homologated by the FIA, how do F1 teams ensure that sensitive data does not fall into the hands of rival teams?

13:23 Norbert says: "That is fully under control, and I am not worried at all that any information would go from one team to another."

13:23 The Lotus' time is three tenths better than earlier, but still leaves Raikkonen firmly at the back after his morning of frowning at steering.

13:23 Webber becomes the latest man to try a set of mystery Pirellis.

13:23 Matti Alaluari: Who had more talent; Mika Hakkinen or Kimi Raikkonen?

13:24 Norbert answers: "I rate both guys very highly. But it is impossible to compare them as they did not really compete against each other. In fact, Mika recommended Kimi heavily and I was convinced from his first laps in the Sauber team in 2001 that he has great talent."

13:25 Di Resta makes a pitstop 10 laps into his run.

13:25 The Force India was consistently in mid 1m30s, then low 1m31s.

13:25 Everyone now on track except Caterham.

13:25 Norbert wants to add to his previous answer: "Mika is certainly one of the best racing drivers ever and still working for Mercedes-Benz - plus he is a great friend."

13:26 Borbely Bogata asks: Do you prefer race weekends in DTM or F1?

13:26 Norbert smiles and says: "One after the other!"

13:26 Senna is still out on softs and after 11 laps his times have gone up to mid 1m33s. The Williams' best pace at the start of the run was high 1m30s.

13:26 Now Senna pits.

13:26 Reports of very, very light rain around Catalunya.

13:27 Selim Kesen asks: Are you really ‘the drift king’ as Schumacher says?

13:27 More spits of rain than actual 'change of plans' rain.

13:27 Norbert answers: "I would not allow myself to challenge Michael's words!"

13:27 Massa brings the Ferrari in.

13:27 Andrew Storcher asks: Mercedes gave us the Uhlenhaut SLR; will we ever see a Haug SLS?

13:28 Norbert asks back: "Would you buy one? I will speak to AMG boss Ola Kaellenius on Monday!"

13:28 Brian Levine: Red Bull has just launched a Mark Webber barbeque in Australia, fashioned from carbon fibre and aluminum cans. Any plans to do the same for Michael or Nico?

13:28 Button comes in too.

13:29 Norbert says: "Let me think about it!"

13:29 A mixed six-lap run for Button, with some 1m23s but also some 1m30s and no real pattern for us to analyse.

13:29 Massa is coming in and out of the Ferrari pit.

13:30 Okay that's all the time we have Norbert Haug. Thank you Mercedes, and thank you Norbert for letting us ask you all those questions!

13:31 Thank you too to all the readers who sent questions in, sorry we couldn't ask them all, there were absolutely loads!

13:31 Frantic first half hour as the long stints start. Di Resta and Senna clearly on race runs.

13:32 Webber comes back in.

13:35 Ricciardo may well be on a race sim too, but no idea what tyre compound he's on.

13:36 Di Resta and Senna much more evenly matched in this stint.

13:36 And our Ricciardo tyre confusion isn't us being daft, by the way, it's because some of the Pirellis are unmarked.

13:36 Webber rejoins.

13:38 And the Red Bull is still on unmarked tyres, so we remain perplexed.

13:38 Button is also back out.

13:39 Looks like Perez may also be doing a race simulation.

13:39 While his boss heads back to work afer chatting with us, Rosberg pits on soft tyres.

13:40 Button is the latest man to decide that running unmarked tyres is a good way of bewildering the easily bewildered AUTOSPORT Live crew.

13:40 Paul di Resta pits. He's fourth fastest at the moment and his last lap was a 1m31.587s.

13:41 Perez meanwhile keeps pressing on with the soft tyres. The Mexican is just about running in the 29s.

13:43 @nobleF1 is taking off to see the people who deal with F1's timing at tests - TSL. If you've got any questions you want him to ask them... send them to live@autosport.com

Di Resta is quickly back out of the pits and now he is on a set of medium tyres.

13:46 Button pits. Just one lap on track for the world champion. Rumours of hydraulic issues as the reason for his lack of morning running.

13:46 Ricciardo's now 13 laps into his race sim in the Toro Rosso, which has so far proven considerably less fiery than yesterday.

13:47 Senna's running even longer. 21 laps so far with just one tyre change in the middle.

13:48 Webber pits having completed just four laps on those mystery Pirellis. Wonder if it's the same set and they are just wheeling them down the pitlane from car-to-car?

13:49 Ricciardo is being given '51' sign on his pitboard, which no doubt means he has 51 laps to go on his race simulation. AUTOSPORT's Jamie O'Leary is speculating that will be followed by more pitstop practise.

13:50 Senna's getting great life out of those soft tyres. He's only dropped a second in pace over the past 10 laps.

13:51 The big 'S' on the inside of Ricciardo's unmarked tyres might indicate he's on softs. Or that they are demarcated for Scuderia... or they've stolen them from Sauber!

13:52 Massa pits.

13:53 Interesting comparison between Senna and di Resta. On soft tyres of similar wear, they were pretty much even-matched.

13:53 But since switching to mediums, di Resta is now taking 3s out of Senna, who remains on the same set of softs.

13:53 Perez has now switched to mediums for this stint.

13:55 Ricciardo is now running 3s per lap faster than he was before his stop - the benefit of fresh rubber. He's in the 29s bracket again.

13:55 Senna, by contrast, has worn his softs out now and he's in the 34s.

13:56 Senna finally pits having done 15 laps on those softs.

13:57 Senna did one more lap than Ricciardo on the softs, but his pace went from 1m30s to 1m34s. The Toro Rosso man lost but just one second during the same stint period.

13:57 Kovalainen pits the Caterham.

14:00 The Finn has now gone back out on unmarked tyres.

14:01 Button sets the fastest first sector of the day. He's on the soft tyres. The lap ends up being good enough to post him second overall - 1m22.103s

14:02 Having done that, the 2009 world champion promptly pits the next time around.

14:03 Rosberg pits the Mercedes, he's completed 12 laps on the soft tyres.

14:03 He faded through 2.2s worth pace over the course of that run.

14:04 Incidentally that compares to the 2.6s dropoff Rosberg lost in the previous 11 lap stint, and 4.5s in the 13 lap one prior to that. All of those were of soft tyres too.

14:07 Di Resta pits again and switches back to soft tyres, as Ricciardo receives the 'pit in' board. Softs off, softs on.

14:10 Perez has been in and out of the pits for another set of mediums. Meanwhile Raikkonen is six laps into his latest stint now for Lotus - his latest lap a 1m27.298s

Kovalainen pits after what was just an out-lap while Raikkonen ends his stint.

14:15 Webber takes to the track again on a set of soft tyres.

14:18 Senna crosses the line with Rosberg right in his slipstream. The Mercedes flicks out of the tow under braking for Turn 1...

14:19 We assume he got by...

14:19 Track is pretty busy right now with only Raikkonen in the pits.

14:20 Well make that Raikkonen and di Resta as the Force India driver comes in.

14:20 And then Raikkonen goes back out.

14:20 di Resta does too, and as he does so, does a practice start at the exit of the pitlane.

14:21 Rosberg did get by Senna. And now he's whizzing by Webber's Red Bull over the startline. AUTOSPORT's Jamie O'Leary speculates that he is enjoying himself.

14:22 Di Resta is now on medium tyres, as Button pits. We think the Red Bull is carrying quite a lot of fuel at the moment.

14:25 We've had a visit from Ferrari's press guru Luca Colajanni, who informs us that the team's drivers will not speaking to the press for the rest of the test. 'It's better that they focus on their job', he says.

14:26 Perez is currently significantly faster than Ricciardo. Daniel is set to come in at the end of this lap though.

14:27 In comes the Australian for another set of softs, and off he goes again.

14:27 Senna pits the Williams.

14:28 Di Resta dashes by Perez into Turn 1, the Scot is lapping 2s quicker on his oldish mediums.

14:29 A ripple of excitement through the press room, though it has to be said not from the actual press, as another tour comes gazing through. Really, what is so exciting about people in front of laptops?

14:31 Senna is using unmarked tyres currently. It's frustrating we know, but we're doing our best! They could softs, they could be something else.

14:32 Senna, Raikkonen and di Resta are all currently lapping in the 1m27s. That makes them the three quickest men on the track at the moment. We also think they are all on mediums.

14:33 Webber pits and is pushed back into the garage... Perez is in too, and Kimi.

14:34 Hmm... It looks like... Yes its raindrops. That would it explain it.

14:35 It's just spitting though. Button, a true Englishman, is unconcerned by this and heads back out on to the track.

14:36 AUTOSPORT's Jamie O'Leary reports that the track temperature has now dropped to 22.8 degrees C. And the sun had disappeared, much to his disgust. Anyone would think we'd sent him on holiday!

14:37 Great action on track right now. Kovalainen, Ricciardo and Perez blast by the pits in unison. 'You could throw a blanket over them' says our northern correspondent.

14:37 Perez scythes past them both in to Turn 1 with some ballsy confidence.

14:38 The times tell the tail as Perez's lap is 1m27.5s, while the other two are in the 31s.

14:39 Rosberg shocks the press centre by leaving the pits on something other than soft tyres. Hards in fact.

14:39 Button is currently on medium tyres and is easily the fastest man on the track right now.

14:39 Perez and Kovalainen pit.

14:40 According the screens in the press room the track marshals report rain at Turn 7 - which is the closest one to the paddock. We could have told them that, oh wait... we did!

14:41 Di Resta pits and is rolled back into the Force India garage.

14:41 Perez's crew have called time on his simulated run too.

14:41 Button and Webber also come back into the pits.

14:42 Everyone bar Ricciardo has now come in or is heading in to the pits.

14:42 But just as we say that Massa heads on out again.

14:43 Ricciardo's last lap was a 1m38s!

14:44 Massa is lapping in the 1m40s as the rain begins to establish now.

14:45 @noblef1 reports: Properly raining now. That looks like the end of decent slick running data gathering for a while

14:46 Everyone bar Ricciardo is now in the pits. The Aussie rookie (ish) has headed back out on a set of inters.

14:47 This, of course, is the first time anyone has had the chance to run a 2012 car in the rain.

14:49 Plenty of teams reporting in on Twitter now.

14:50 @clubforce says: Race distance completed for @pauldirestaf1 just before the rain arrives in Barcelona. 108 laps for the day so far and a best of 1:22.446.

14:51 @Lotus_F1Team says: A number of setup runs planned for this afternoon, so expect Kimi to be diving in and out of the pits a few times... #F1 #Raikkonen #Iceman

14:51 @OfficialSF1Team says: #C31 is back in the garage. Just when the rain set in. #Checo completed 100 laps so far. Team is busy with investigating the fuel system.

14:52 Unsurprisingly not all of our international colleagues are happy about the lack of Massa and Alonso access...

14:53 @InsideFerrari has felt compelled to respond: @laiaferrer It is an hard decision and we fully understand the unhappiness of the media...

14:54 Back on the track Ricciardo is lapping in the 1m47s, which gives you some indication of how wet it has become out there.

14:54 AUTOSPORT's Jamie O'Leary reports that there is very little spray from the rear of the cars yet though.

14:54 Massa is back out on track.

14:57 More from Ferrari on their decision not to let the press talk to the drivers... @InsideFerrari: The decision has been taken to keep the whole team fully focused on the job and there is not any polemic intent behind it.

14:58 You'll notice our little weather icon had changed again... That is to signify O'Leary's excitement at the re-emergence of the sun over the Circuit de Catalunya. It is, however, still drizzling.

14:59 Senna's heading out back on track too.

15:02 Massa's back in the pits. His car is shut down and wheeled back into the garage.

15:04 Following on from Ferrari's decision, Caterham has kindly made it clear that it will happily speak to the press afterwards. @MyCaterhamF1: *throat cleary noise*... Heikki Kovalainen will be chatting to any members of the media who wish to join us at 1830 tonight... *cough*

15:05 Ricciardo is getting on with it. He's worked himself down to a 1m43s time now with his inters.

15:05 Sorry, we're wrong about that bit. He's on a nice set of soft slicks actually.

15:09 Rosberg leaves the pits as Ricciardo returns to it, his slicks experiment apparently not having been entirely successful.

15:11 Senna and Massa are both out on track currently, but neither can break the 1m43 barrier currently.

15:12 It's pretty damp out there still, and with 45 minutes to go it's to see any headline times happening now.

15:15 @noblef1 has returned from his visit to meet the TSLTiming people: "Just had a fascinating look behind-the-scenes at how F1 testing timekeepers TSL Timing goes about its business. The company has been the timekeeper of choice for the teams for about five years now, having done every test over that period. Set up on the second floor of the race control tower, directly above the finish line, it is responsible for logging each lap, sector time and speed trap figure for every car and every lap. At the end of each day, it sends 87,000 lines of data to each team from everything it has gathered. So, over the 12 day pre-season testing period we have had, that is 1,044,000 lines of data for each team to pore over - and somewhere in there is the answer to help us work out exactly who is quickest overall!"

15:15 Good grief. There are now reports of hail down at Turn 1. You don't want that to be hitting your visor at 300k/mh.

15:16 We don't have a weather icon for that by the way.

15:16 RED FLAG

15:17 Massa and Senna are still on track. We are waiting for the cause of the stoppage. It could be ice-related.

15:17 Massa is back in the pits, but Senna has apparently stopped at Turn 10.

15:19 Our resident Aussie educator @avlmelbourne reports that Senna may have had an 'off'.

15:20 Nope, he's changed his mind about and now reckons the Williams just stopped.

15:20 One of AUTOSPORT writer Sam Tremayne's beloved flatbed trucks is now on the scene.

15:22 Bruno decided to park the car a long way from the track, which explains the confusion over why his car appeared to be in the gravel. Probably wise given the conditions.

15:26 There doesn't appear to be much of a rush about removing the Williams as the session moves towards the last 30 minutes of the day.

15:26 The weather seems to have calmed down, though our team reckons it still looks damp from the comfort of the press room window.

15:29 The arrival of the latest batch of curious (we're guessing mainly) Spaniards walking through the press room hails a return to green flag conditions.

15:29 Rosberg is the first to hit the track for Mercedes.

15:31 Rosberg comes straight back in again. He was using inters by the way, which are still the required bootwear out on track right now.

15:32 Massa hits the track again, if for no other reason to avoid any snooping press ignoring Ferrari's announcement that its drivers won't be talking to them this week.

15:33 Massa's first lap is a 1m48.021s. That just shows how damp it still is out there.

15:35 There are 26 minutes to go, and fit looks like Sauber is going to end the day the fastest time recorded so far at Barcelona in 2012.

15:35 Ricciardo rejoins Massa on track and this time the Toro Rosso is equipped with a set of full wets.

15:36 We're still trying to ascertain the tyre type Massa is on.

15:37 Ricciardo returns straight back to the pits and, yep you guessed it Toro Rosso crack into some pitstop practise.

15:38 Perez heads back on to the circuit with a set of inters.

15:39 Having been sent back out on inters, Ricciardo's mechanics are blowing water out of the pit box with fans before he gets back.

15:39 Speaking of which, here he is again.

15:41 Massa, we can confirm, is on inters, as is Rosberg.

15:42 A marshal just braved it and run out to the edge of Turn 1 to collect what looked like a piece of car on the entry to the corner.

15:44 Perez's 1m48.405s seems to be as quick as anybody is capable of going as we cruise into the last 15 minutes of the session. Just the Mexican, Massa and Rosberg out on-track right now.

15:45 Just as we say that, Perez bangs in a 1m45.181s.

15:48 @avlmelbourne reports that quite a few fans have braved the hail and rain and waited out the red flag to watch to the end of the session.

15:48 Perez passes Rosberg into Turn 1.

15:49 Button has recorded just 44 laps today, and hasn't been out on track since the beginning of the drizzle. But he's going to end the day second fastest, just 0.009s slower than Perez.

15:50 @noblef1 reports that only part of McLaren's Melbourne upgrade appeared on the car today - the revised splitter concept under the nose.

15:51 Perez till lapping on inters - his latest lap a 1m44.7s

15:52 Ricciardo meanwhile is carrying with his pitstop practice. His combined with all Jean-Eric Vergne's, the team must be way up in to the 30s for stop rehearsals this week by now.

15:54 Rosberg has come back into the pits to dry off.

15:55 Ricciardo squeezes another pitstop practice in before the end of the session. The painted stripe in the pitlane looks tricky to negotiate in this weather.

15:56 Just three drivers out there now and only Perez and Massa are banking flying laps.

15:56 Make that just Massa as Perez pits.

15:57 Rosberg heads back out in the closing stages.

Perez comes in, secure in the knowledge that he will be quickest for today.

16:00 Perez rejoins the party, but it's a little late to get a flying lap in now. Ricciardo's team practise a full front wing change this time.

16:01 The chequered flag is out, but Ricciardo got out just in time to secure yet another practise stop...

16:02 So Perez ended the day fastest of all with a time he set this morning - 1m22.094s, ahead of Jenson Button and Daniel Ricciardo. Felipe Massa was fourth fastest, di Resta fifth for Force India and Bruno Senna sixth.

16:03 Webber completed 70 laps for Red Bull in the revised RB8, but was only eighth quickest behind Heikki Kovalainen's Caterham. Rosberg was ninth for Mercedes and Raikkonen - who had steering issues this morning - completed the times in tenth.

16:05 Thank you for following us today on AUTOSPORT Live. It's been a fun day what with the weather, a visit from Norbert Haug and some quick laps before it rained.

16:06 We'll be back on tomorrow morning just before 0800 GMT, 0900 (CET), to give you all the news live from the final day of pre-season testing before Melbourne. Until then, see you later!