1610: Now seems like a good time to call it a day. Thanks for your company. There's just one more day of testing on Sunday before we do this for real in Bahrain. See you tomorrow morning, take care.

Mercedes on Twitter: "That's it for the day and Nico's top of the timesheets from the quick laps this morning... 128 laps in total with a quickest of 1:20.686."

1600: As expected the session comes to a close. Here's a quick summary of the times: Rosberg (1:20.686), Buemi (1:21.413), Button (1:21.450), Barrichello (1:21.975), Massa (1:22.344), Petrov (1:22.523), Sutil (1:22.606), Vettel (1:23.254), Trulli (1:25.059), Kobayashi (1:26.216), Glock (1:26.305).

1557: A fifth red flag comes out, that could be that for the day people. Barrichello is the cause for the second time today, this time he just stopped on the track.

Force India on Twitter: "Dr Mallya is in the garage talking with the team while Adrian makes his final run for the day."

1551: It's getting busy out on the track as the teams put in some glory runs. Barrichello takes his Williams to third with a 1:21.975 while Button improves to fourth with a 1:22.127. Virgin's Timo Glock sets a time of 1:26.305.

Mercedes on Twitter: "Small technical gremlin stopped Nico out on track. All fixed and he's heading back out again very soon... "

BBC Sport's Sarah Holt on Twitter: "A man who has been clasping a red Ferrari helmet to his chest outside the Mercedes trucks all day.... is still there."

sawbospur on 606: "If I were McLaren I would be a little concerned, unless they are sandbagging, they have not looked as quick as Ferrari and Red Bull apart from briefly in Jerez. Williams also look on the pace today."

1542: We are off again, there's just 18 minutes of running left before the chequered flag falls.

Renault on Twitter: "Another red flag has stopped Vitaly's long run. When it goes green he'll be running till the end."

BBC Sport's pit-lane reporter Ted Kravitz: "Michael Schumacher's personal doctor, Johannes Piel, is here again to keep a close eye on his patient's neck. Meanwhile, on the track Felipe Massa's race simulation for Ferrari was interrupted by the red flag for Nico Rosberg. The Brazilian's pace on the medium tyre was an underwhelming 1:26.4 on average but with the fuel going down and on the soft tyres he's been in the 1:22/1:23 bracket. Massa's pit stop took 7.5 seconds after the rear jack was slow to drop the car. The fastest pit stop seen under race conditions on Saturday has been Rosberg's at 5.5 secs. I also have news on Virgin. The team changed the car's fuel pump overnight and when Timo Glock got through a few laps running on Saturday they discovered a leak. They traced this down to a split o-ring and had to take the car to pieces to change it which ended up taking a large part of the afternoon. It's now repaired and the team are still hoping to get in some running before the flag falls."

1330: Another red flag. This time the Toro Rosso of Sebastien Buemi comes to stop. Virgin are getting frustrated. Here's their latest tweet: "And red. What is going on?"

1525: As the session resumes, Ferrari reveal that "another race simulation successfully completed for the F10". It is difficult to compare the times set during these practice sessions but if Massa did set those quick times with a fair bit of fuel on board, then Ferrari really are looking handy.

BBC Sport's Sarah Holt on Twitter: "Rosberg looks at the back of his car, gives his legs a good stretch before being ferried back to Mercedes HQ. The car will join him shortly."

Mercedes on Twitter: "Red flag... our car this time. On the recovery truck and on its way back."

Virgin on Twitter: "Red flag! Ideal :-( "

1518: Virgin's Timo Glock finally gets a time on the board, it's 1:30.814. Now there's a red flag. The Mercedes of Nico Rosberg has stopped on the track.

Force India on Twitter: "The boss is here. No more cup action methinks."

Incubus on 606 "If Massa goes on to complete a full race simulation, meaning that he'd still have 20 laps worth of fuel onboard, then this pace is highly impressive."

1511: Looks like Virgin are finally ready to rejoin the fray. Here's their latest tweet: "And off we go. That was a long job but necessary for safety."

1510: Felipe Massa's Ferrari is showing some pace after getting some new tyres during a long stint. The Brazilian sets the third fastest time of 1:22.344 while Vettel goes seventh with a time of 1:23.968.

BBC Sport's Andrew Benson: "After stopping out on the track during testing on Friday, Vettel said he was 'not worried' about the number of times the Red Bulls had suffered this problem in testing, adding: 'I don't think we have to fear reliability issues yet. Everything that happens I think is normal because we have a new car and new parts and everything is slightly different in the design. Small parts and little pumps have changed and sometimes you realised we should have done it a little differently but we are on top of those things quickly.' He may well be right, but there is little doubt that Red Bull have had more problems in this area so far than the other top teams."

Virgin on Twitter: "Just firing up, then a few more minutes and we should be good to go."

Mercedes on Twitter: "105 laps for Nico so far! Very valuable mileage on his final day of testing."

1441: Here's a quick timings update for you. Renault's Vitaly Petrov is up to third on the timesheets thanks to a 1:22.523. Red Bull's Vettel has improved to 1:24.331 but is still eighth.

BBC F1 commentator Jonathan Legard in Barcelona: "A Red Bull engineer has just told me it's been 'a hell of a day' before disappearing into the garage. Red Bull boss Christian Horner then emerged to tell me that the team have made a precautionary oil pump change to the car and now they are hoping for some uninterrupted running on a drying track. Let's see."

BBC Sport's Sarah Holt in Barcelona: "At a 'Breakfast with Branson' media briefing this morning, Timo Glock reminded us all how long he'd been out of an F1 car since wounding his leg and cracking a vertebrae during qualifying for the Japanese Grand Prix. He said the last two months have been 'driving him crazy' but his frustration can hardly have been eased during testing for the new Virgin team. Glock saw the car's front wing fall off in Jerez and the former Toyota driver is yet to post a proper time here on Saturday because of more issues with the car. Technical director Nick Wirth says there have been problems with the fuel system but, in spite of this, he remains resolutely upbeat. 'There've been good times and bad times,' he said. 'Small design issues on the car have caused us problems and hydraulic issues have slowed us down. But all I ask is that you judge our performance when we get to a certain rate of development, and we are excited about what we can deliver within the next year.'"

BBC Sport's Sarah Holt in Barcelona: "More news from pit-lane reporter Ted Kravitz on what Felipe Massa is up to. 'Massa is doing a full race simulation this afternoon. He is on lap 20 and will be making his one and only pit stop soon.'"

Lotus on Twitter: "Race distance completed, making a couple of modifications - will be back out again later."

Force India on Twitter: "Oh dear. Test boredom nigh. One of guys walking around with a cup stuck on his headphones. He doesn't know he has a cup stuck to his head. Maybe he's just testing how much it's raining? Hmmm."

Virgin on Twitter: "All going back together now, so hopefully not too long... "

1406: Ferrari's Felipe Massa, runner-up to Lewis Hamilton in the 2008 world championship, is out on a stint that has meandered from the 1:27s to the 1:29s and which is now in the 1:26s. Red Bull's Sebastian Vettel completes his first flying laps of the day and sets the eighth fastest time with a 1:24.892.

Force India on Twitter: "Adrian's back in after a performance run. Seems quite happy, says the car feels 'consistent'. It's raining again though now."

BBC F1 commentator Jonathan Legard: "Day two in Barcelona and I've been speaking to a McLaren engineer who says the team are not at all fazed by Ferrari's pace and performance. They've added new aerodynamic parts to Jenson Button's car and they should give a verdict after Saturday's running. I gather there'll be another big update for Bahrain. McLaren are optimistic they'll be firmly in the mix in the first race."

BBC Sport's Sarah Holt on Twitter: "I have just been saved by one of McLaren's emergency egg sandwiches."

1343: Seven-time world champion Michael Schumacher has been speaking to the great and good of the media and has said that his former team Ferrari are in good shape for the start of the new campaign. Interestingly, he also backtracks on the comments he made yesterday that his new Mercedes team "we are not perfectly in the position we would like to be, which is competitive to win straight away". Read all about it here.

Renault on Twitter: "The morning rain means we'll run a shortened qualy sim this afternoon. And then we'll get as much of the race distance done as possible."

Mercedes on Twitter: "Back out after the lunch break now and Nico will be working on race procedures for the afternoon... "

1328: Oh dear, more problems for the new Virgin team. They have just tweeted that "standard checks over lunch revealed a leaking fuel o-ring which is now being changed". That follows front wing failure during the first test in Jerez, hydraulic issues during the second test at the same venue which restricted them to only 144 laps, while testing has been restricted in Barcelona because of Lucas di Grassi's crash on the opening day. As yet, Timo Glock has not posted a flying lap time today.

1317: Lotus technical chief Mike Gascoyne is reporting that Trulli's rear tyres are "dropping off". Conditions are improving in Barcelona so hopefully a drying track will give us some quicker times. Meanwhile, on 606 , some clever contributor has composed a little ditty about the weather in Spain. With chords and everything. Get involved.

1312: Reigning world champion Jenson Button is getting some laps in for McLaren. He sets the fifth fastest time of the day with a 1:23.531.

Claire Williams of the Williams team on Twitter: "Mechanics getting car ready for Rubens to go back out for an afternoon of race simulation work."

Lotus technical chief Mike Gascoyne on Twitter: "Jarno resuming race distance for last 25 laps on dry tyres."

Force India on Twitter: "Nice shepherd's pie lunch now ready for afternoon. (That's the team, not Adrian. He had something a bit more 'athletic'). Performance work this afternoon for Adrian. Track is still wet but there's work to do so we're just going to have to grin and bear it... "

1300: The green flag drops and we are good to go for the final three hours.

BBC Sport's Sarah Holt on Twitter: "Lunch at the Mercedes team was interrupted by a media conference given by Michael Schumacher. Munching at Mercedes suddenly became busy... "

Renault on Twitter: "The paddock is packed out with fans during the lunch hour. Vitaly has been kept busy signing autographs."

1233: There's some live handshaking, sorry football, going on today. The wonderful Caroline Cheese is your host for all of Saturday's Premier League action.

1209: We've just posted the latest F1 gossip round-up from the world's media outlets, and there's some interesting titbits in it. Apparently Williams novice Nico Hulkenberg's fastest time on Friday was set on super-soft tyres, while Ferrari's Fernando Alonso used soft tyres for his quick lap. There's also some nicely tasty quotes from F1 hopefuls Stefan Grand Prix about the beleaguered US F1 outfit. Read it all here.

1201: That's it, a frustrating morning comes to a close. The cars will be out again from 1300 GMT, let's hope for some drier running. Here's a quick summary of the times so far: Rosberg (1:20.686), Buemi (1:21.413), Sutil (1:22.951), Massa (1:23.490), Barrichello (1:23.976), Trulli (1:25.059), Kobayashi (1:26.216), Petrov (1:26.346), Button (1:36.667). There's no time posted yet for the Virgin of Germany's Timo Glock.

From Momo in London via text on 81111 or +44 7786200666: "Is anyone else extremely eager to see what Kamui Kobayashi can do this season? His two drives last season were in my opinion exceptional for a rookie in a poor car. The guy seems fast, but also a great racer too. One to keep an eye on definitely."

Incubus on 606 "This rain's really a pain. On top of that with the mix of drivers carrying out race simulations while others go for short stints, we can't even get an indication of who's quick in the rain."

1153: There's still some light drizzle in Barcelona. Rosberg has set one of the quickest wet times today, 1:34.665, while Lotus technical chief Mike Gascoyne tweets: "Small off from Jarno. Will clean car and finish last 25 laps of race sim after lunch."

BBC pit-lane reporter Ted Kravitz: "Williams have just done an overheating test. They stopped Rubens Barrichello in the pit box for just over a minute, which is the longest time they can imagine he would be stationary during a race weekend - on the grid. The car passed with flying colours and nothing overheated but these conditions - 11C and light rain - are hardly representative of what the team will face in Bahrain and Malaysia. It's still a box they need to tick before the season starts. Meanwhile, at Mercedes, Nico Rosberg appears to be running with a lot less rear wing than any of the other cars on track. His race engineer Jock Clear is taking the time to go through a variation of aero levels with different suspension settings."

Force India on Twitter: "Adrian now heading out for four timed laps before lunchtime break."

Renault on Twitter: "Lunchtime! The boys will eat in the back of the garage. Today's highlights are spicy chicken wings and chilli con carne!"

Lotus technical chief Mike Gascoyne on Twitter: "Drying track destroyed the inters. Now raining more so quick stop for new inters as no tread left on original set."

1135: Ferrari are taking an early lunch. Don't blame them. Here's the latest from the team: "We've anticipated the lunch break in order to have more time to work on the car. It's pointless to run on a track with this condition."

1128: The weather in west London is as moody as a John Terry/Wayne Bridge handshake. This must be the tail-end of the nasty stuff that is currently over Spain. Drizzle in Barcelona, race simulations ahoy for the likes of Kamui Kobayashi (Sauber) and the Lotus of Jarnio Trulli.

BBC Sport pit-lane reporter Ted Kravitz: "Rubens Barrichello's off in the gravel has been confirmed by Williams as just a spin while he was braking into the corner. The car will be ready to go back out shortly. Being down in the pits has also given me a first chance to look at the Mercedes diffuser. It seems the team have gone down a different design route this season with an up-swept double diffuser rather than the more open V-shaped hole the team deployed on the 2009 Brawn (and funnily enough, that's the design that new team Lotus have gone for). Mercedes will have a new version of their new-look diffuser in Bahrain. Felipe Massa has been in and out again briefly for Ferrari. The car has a really deep growl - I wonder if they are experimenting with exhaust pipe lengths?"

BBC Sport's Sarah Holt on Twitter: "I have been out of course for contraband chocolate, smuggled for me and my peckish photographer friend from Sauber's stash."

From anonymous via text on 81111 or +44 7786200666: "Don't be fooled by Michael Schumacher's comments, he is one of the few drivers on the grid who can squeeze a couple of tenths out of even the very worst car. When it comes to Bahrain we will see what his car is capable of."

Force India on Twitter: "Still wet on track but not raining any more. We're waiting to see if it dries a bit more before going out again."

1113: I think it's going to be one of those very frustrating days today I'm afraid. Lotus technical chief Mike Gascoyne says that "track was drying a bit but Jarno [Trulli] reporting raining more now and times dropping from 1:42s to 1:.44s". Stick with it though people, we'll get through it together.

1107: Renault's Vitaly Petrov, Russia's first F1 driver, has only clocked a few laps today. Here's the latest from the team's Twitter feed: "Track is drying so we will start set-up work with various fuel levels soon. After that it's a qualy sim and race distance to end the day."

BBC Sport's Sarah Holt in Barcelona: "Virgin Racing backer Richard Branson has responded to Ferrari's swipe at the four new teams due to line up on the 2010 grid. An anonymous scribe called the Horse Whisperer wrote on the Ferrari website that the new teams were a legacy of "the holy war waged by the former FIA president" against manufacturers. Branson has bitten back in Barcelona. The tycoon said: "F1 needs new teams, and Ferrari won the battle of making sure the new teams are shackled. It's sad to see Ferrari carrying on with those kind of words. We've had the same amount of practice time as others like Ferrari, who have had years and years to get their cars to a certain stage. We're not complaining about it; we're happy to get on with it. We will make them look better for a year or two until we catch them up and ultimately the new teams will give Ferrari a run for their money, particularly as budgets come down. We've already proved sceptics wrong by producing a car within a budget - but this is only the beginning."

1055: We are back running in Barcelona. Here's a summary of the times so far, Rosberg is top, with Toro Rosso's Sebastien Buemi (1:21.413), Force India's Adrian Sutil (1:22.951) and Ferrari's Massa (1:23.490) falling in behind.

Ferrari on Twitter: "Track condition is very poor with low grip. It does not make too much sense to run now."

BBC Sport's Sarah Holt on Twitter: "Rubens has taken his helmet off and has been ferried off in the red people carrier. Meanwhile, four Williams engineers are examining the car. And here comes a trusty truck to hoist it away to the pits... Former Williams driver Nico Rosberg is still top for Mercedes by the way."

1042: We have the second red flag of the morning. And it's the Williams of Rubens Barrichello that has visited the gravel at turn five. BBC Sport's Sarah Holt is reporting that the Brazilian is "very much stranded".

1037: You know the drill by now, you get in touch and I'll put it up. Simples. Here's how you do it, there's 606, you can text me on 81111 (UK) or +44 7786200666 or you can use Twitter. And no, I haven't changed the photo yet. Don't keep me hanging now.

From Stargazer on 606: "Mark, be grateful that it is only raining a little. Three quarters of Spain is battening down the hatches for what the media are calling "the perfect storm" - a system that is expected to produce 100mph+ winds today. Barcelona is only on yellow alert (which has risen from yesterday's "no alert" provision for today)."

BBC pit-lane reporter Ted Kravitz: "Jenson Button's final day of testing for McLaren didn't get off to the perfect start as he stopped on the track during his installation lap. It was a minor electrical glitch but it did not take long to fix and Button was soon back out. In the last half hour he's been doing pit-stop practice. Red Bull's gamble on a late start didn't quite pay off. The team decided to keep Sebastian Vettel inside the garage to test some components but it looks like they've missed the window for dry running."

1019: Right, some revealing chat after yesterday's testing. Seven-time world champion Michael Schumacher think that his Mercedes team will not be able to win the first race of the season in Bahrain. "We are not perfectly in the position we would like to be, which is competitive to win straight away," he said. Lewis Hamilton, meanwhile, is cautiously optimistic that his McLaren is better than the dog he started with last season. "We're in a much stronger position than last year. It feels all new, light years ahead of last year, but we still have a lot of work to do. It seems like Red Bull are quick, clearly some teams are very fast. We still feel we have work to do."

Virgin on Twitter: "Timo [Glock] just gone out on wets. Shame - we could do with some more dry running."

BBC Sport's Sarah Holt in Barcelona: "It's the penultimate day of Formula 1's pre-season testing and the weather has reverted to testing form by presenting us with overcast skies, temperatures of 9C and the odd spot of rain. Despite the overhead gloom, the teams are optimistic that they can fine tune their cars before the opening race on 14 March. Red Bull, McLaren and Mercedes plan to add further updates over the weekend and hope to see that converted into a step-up in performance on the track. Eagle eyes spotted a modified front wing and shark fin engine cover on the Ferrari on Friday, when a fiery Fernando Alonso set the second fastest time. F1 aficionados agree that Ferrari have got their nose in front. Can anyone catch up? The teams have two days left to prove they can."

Lotus technical chief Mike Gascoyne on Twitter: "Weather not looking good. A race distance is on the test list so we may as well get on with it."

Lotus on Twitter: "Can't see the mountains now so the weather's definitely worsening. Mood in pit is good after solid start this am."

0948: Some quick updates for you. There's been one red flag, caused by the McLaren of Button stopping on his first lap of the day. Mercedes driver Nico Rosberg has set the fastest lap of the morning, a 1:20.686, which is just off the fastest of Williams driver Nico Hulkenberg on Friday. Unfortunately for the teams, there is now more bad weather in Spain with light rain falling at the Circuit de Catalunya.

0940: Hello you. World champion Jenson Button, Ferrari's Felipe Massa and Williams driver Rubens Barrichello are all in action on this, the third day of the final pre-season test in Barcelona. Let's see what they've got.