1650: That's me done. Many thanks for every single one of your contributions. Make it your duty to stay across bbc.co.uk/f1 for all the very latest news on Bahrain and reaction from Barcelona, where Felipa Massa topped the timesheets in the penultimate pre-season test event. It would appear we're heading back to the Circuit de Catalunya for the fourth and final test on 8-11 March, so be sure to join us then. Adios.

1640: ***NEWS JUST IN*** F1 teams have agreed to test in Barcelona from 8-11 March instead of in Bahrain, Williams chairman Adam Parr has told Reuters.

1630: Reaction on Bahrain is already beginning to filter through from Barcelona. "They [the authorities] know what's going on, so the right decision is made," says Red Bull driver Mark Webber. "I made my decision yesterday which was pretty clear - read the papers. They know what's going on out there and they've made their call so let's go to Melbourne. Back to the good old days. It would have been nice to go to Bahrain but we have to wait a bit longer to have our first race and that just happens to be my home race and always looking forward to going down there. It's a sensational event, I look forward to it. We're in good shape as a team so we hope to go there and have a very good result of course. A lot of [questions] going into the grand prix, we've another test still to go."

1625: That's what happened on the track but, understandably, most of the action was overshadowed by events surrounding Bahrain. Both the final pre-season test event and the season-opening Grand Prix, due to be staged in the Gulf state on 3-6 March and 13 March respectively, have been called off. We understand the 2011 campaign will now start with what was meant to be the second race, the Australian Grand Prix, on 27 March.

1615: So Massa takes the spoils thanks to his late flying lap - an effort of one minute, 22.625 seconds. Webber, pacesetter for much of the day, is forced to settle for second with a 1:23.442 while Sebastien Buemi (1:23.550) comes third and Nick Heidfeld (1:23.657) fourth. A last-ditch charge by Lewis Hamilton (1:24.003) puts the Englishman fifth-fastest, with Pastor Maldonado (1:24.057), Adrian Sutil (1:24.177) and Sergio Perez (1:24.515) in close attendance. Jerome D'Ambrosio (1:26.501) improved as the day wore but seven-time world champion Michael Schumacher (1:27.079) finishes 10th-fastest and Jarno Trulli (1:29.992) is bottom of the pile after a pre-lunch shunt into a wall.

1600: Down comes the chequered flag and it's Felipe Massa who finishes top of the timesheets at the pre-season test event in Barcelona. Good job, Ferrari.

Laura, Manchester, via text on 81111: "Why is everyone giving the McLarens such a hard time?They're a test down on the other big teams and from what I've seen have done a pretty good job! Not everything is about raw pace - although the McLaren seemed quick yesterday - or the Red Bulls would have won last year's constructors trophy half-way through the season! I'd rather they had solid race pace than one off quick pole laps and they're undoubtedly the best team at development through a season! Good luck to them this year."

1557: D'Ambrosio gets himself into the top 10 while Heidfeld also improves his time but remains fourth.

1555: Back in Barcelona, we have a GREEN FLAG but only five minutes remaining. Heidfeld and Hamilton leap into the top five but Massa remains unmoved. Drama on and off the track.

Boycey, Bingley, via text on 81111: "From what I've seen over the first three tests, Red Bull Ferrari and Mercedes are the teams which I would say will be challenging for wins at the start o f the season. McLaren will get stronger as the season develops but it may be too late. Hoping Schumi roars back to form in the Silver Arrow!"

1548: This could be a hammer blow to the teams who were planning a series of flying laps before the close of play. Schumacher's Mercedes is crane-lifted on to the recovery truck and hopefully we'll get a good 10 minutes of testing before the chequered flag.

1544: Schumacher comes to a stop at Turn 10 and that can only mean one thing - another RED FLAG.

1540: A tense finale indeed. Felipe Massa smashes out the first sub-1:23 lap of the day to go top of the timesheets. It's an effort of one minute 22.625 seconds and knocks Webber off his perch by 0.817 seconds. Advantage Ferrari.

Whitters, Shrewsbury, via text on 81111: "Really hope McLaren are keeping something back for the last test or the start of season as I'm a big Lewis fan and I'm not optimistic!"

1530: Into the pits go Massa and Webber, out comes Hamilton. The 2008 world champion joins Schumacher and D'Ambrosio on the Circuit de Catalunya tarmac.

BBC F1 commentator Martin Brundle on Twitter: "Toro Rosso looks solid, Buemi is chasing the throttle as hard as anybody. Watching the cars, it's definitely going to be a wild + variable season."

1525: That could be the end of the test for Williams, we'll see. Anyway, the GREEN FLAG is fluttering so we're back under way - 35 minutes to win it. Mark Webber of Red Bull still leads but we could be in for a tense finale.

1518: And just as I was getting excited, out comes the first RED FLAG of the afternoon. We're hearing Pastor Maldonado has brought his Williams to a halt on the track. The Venezuelan was on a race run and may well have run out of fuel.

1515: At last some proper movement on the timesheets. Felipe Massa gets his Ferrari F150th round in 1:23.531 to go second fastest, 0.089 seconds behind Webber. Expect more quickies like that as the session draws to a close.

BBC Radio 5 live F1 commentator David Croft on Twitter: "Just to let you know guys my info is that no decision on the Bahrain GP or test has been taken yet. FOTA to discuss situation at 4pm UK time."

BBC Sport's Sarah Holt in Barcelona: "As Ted was saying, we will have more on the future of the Bahrain test very soon. In the meantime, I have an interesting snippet about what could happen if the test in Bahrain is cancelled. The teams will most likely stage an alternate test here in Barcelona and will mull over whether to hold a three-day test beginning on 28 February or a four-day test on 8-11 March, if the Bahrain Grand Prix is also postponed. We shall see."

1458: ***BAHRAIN UPDATE*** BBC Sport understands the F1 test in the Gulf state is likely to be cancelled. An F1 team, which did not want to be named, told us the decision will be announced later on Monday. The source also expects the season-opening Bahrain Grand Prix itself, set for 13 March, to be postponed because not doing so would be "incendiary" to the political unrest.

1456: Approaching the final hour and Webber still heads the charts with his lap of 1:23.442 from Sebastien Buemi (1:23.550), Pastor Maldonado (1:24.057), Adrian Sutil (1:24.226) and Felipe Massa (1:24.929). Massa and Maldonado have both chalked off an unrivalled 96 laps. Lewis Hamilton (1:25.094) remains sixth, Nick Heidfeld (1:26.203) seventh and Sergio Perez (1:26.914) eighth. Michael Schumacher (1:27.079) finds himself down in ninth but has 91 laps to his name. Jerome D'Ambrosio (1:29.692) and Jarno Trulli (1:29.992) have swapped positions in the bottom two places.

BBC pit lane reporter Ted Kravitz: "There is a bit of jumping the gun going on over cancellation of the Bahrain test. All the teams are holding a meeting via conference call at 1600 UK time - which is when the test day ends here in Barcelona - where a decision will be officially made. As we've been saying all weekend, we do expect the test to be cancelled - but let's wait until it's official."

1439: Here's Ted with an update on the final pre-season test event in Bahrain, which some outlets are reporting has been cancelled...

BBC F1 commentator Martin Brundle on Twitter: "Drivers will complain like crazy but I'm really liking what I'm seeing out on track. They are really having to drive the cars, loads of mistakes. Mercedes has poor traction, McLaren looks shocking as if on cold tyres, Red Bull+Ferrari+Renault+Williams all pounding round."

1432: Some more testing insight coming up from Mr Brundle...

BBC Sport's Sarah Holt in Barcelona: "We are in the midst of a nice spell of track activity as the Barcelona test winds down with a final flurry of action. Mark Webber has set out on a 17-lap run for Red Bull and he is doing steady tours in the 1:30s. Felipe Massa has just returned from a decent chunk of laps for Ferrari, which were also mainly in the 1:30s. Lewis Hamilton is now back on track after tantalisingly coming out for an lengthy out lap and then deciding not to bother and going back into the McLaren garage"

1426: No change on the timesheets, so it's still Webber - Buemi - Maldonado - Sutil - Massa - Hamilton - Heidfeld - Perez - Schumacher - Trulli - D'Ambrosio. Hamilton was nowhere to be seen at the start of the session but he's just popped out to practice some starts at the end of the pit lane. Massa, meanwhile, has completed a nine-lap run, taking his total for the day to 94. Yes, ninety four! He'll be circling the Circuit de Catalunya in his sleep tonight.

John, still doing crazy maths in Belfast, via text on 81111: "Hypothetically speaking, if Messrs Webber and/or Alonso etc were to put the stickiest rubber boots on, have a Coke bottle's worth of fuel in, use full Kers and wing operation, how low could they go compared to last year's pole? One minute, 20.5 seconds maybe? I'm hoping its that close. I know the cars are very different & the temps lower, but surely someone smart has a wee computer program that will come up with a figure that will give us a ballpark idea as to how much they are sandbagging!"

BBC Sport's Sarah Holt in Barcelona: "You may remember on Saturday that Ferrari's Fernando Alonso called Red Bull his biggest rival, well guess who Mark Webber has picked? Yes, Webber named Ferrari, and why? 'Fernando works for them and he's pretty handy,' Webber said. Anything else? 'Ferrari finished the year very strong and they've come out of the gates very strong; the car is running, it's always out there, they aren't hanging around when they are out there, they're pretty quick and the team are always organised.' What about McLaren, the only other team to join Red Bull and Ferrari as race winners in 2010? 'We're not sure what's going on with McLaren,' Webber mused. 'It's obviously early days with their car'."

1400: Right then, here we go. Two hours of testing before the lights go out on the Barcelona test. Word is we'll see long runs for most of the afternoon and then qualifying simulations at the end of the day, so the timesheets might not alter drastically for a while yet. All of which means it's down to you good people to help me fill this page. You know the process - get in touch via the Twitter hashtag #BBCF1 or contact me directly @bbcsport_david and we'll try to get your questions answered. SMS is also an option, the text number being 81111 (UK).

BBC F1 commentator Martin Brundle on Twitter: "The feeling here is that there will be further tests in Spain and not Bahrain tests. Information and misinformation galore."

1354: No update on Bahrain since about 1100 GMT, when it emerged that F1 boss Bernie Ecclestone was set for talks with the Gulf state's crown prince to decide whether the season-opening Grand Prix - due to be staged on 13 March - would be postponed.

Renault GP on Twitter: "After a quiet morning, the priority this afternoon is to get miles on the car. Nick will simulate a race distance on new and scrubbed tyres."

1345: The sun's out at the Circuit de Catalunya and temperatures are up to a pleasant 15 degrees Celsius. Webber leads the way from Sebastien Buemi (1:23.550), Pastor Maldonado (1:24.057), Adrian Sutil (1:24.226) and Felipe Massa (1:24.929). Massa has now completed more laps than anyone else (71). Lewis Hamilton (1:25.094) is sixth, Nick Heidfeld (1:26.203) seventh and Sergio Perez (1:26.914) eighth. Michael Schumacher (1:27.079) finds himself down in ninth but almost challenging Massa for running time, while Jarno Trulli (1:29.992) is 10th and Jerome D'Ambrosio (1:31.713) bottom of the pile.

1335: Out comes pacesetter Webber for a first run of the afternoon. He currently tops the timesheets with a lap of 1:23.442.

Doug, Norwich, via text on 81111: "How much information can we really get out the times in testing?"
Fair point, and for us on the outside the answer to that is "not a great deal". We're able to monitor times but receive little-to-no info about tyre choice, fuel loads or strategies. Yet it's still interesting to see which drivers top the timesheets each day, how many laps they complete and who experiences problems at what is a crucial time in their pre-season preparations. While the info we receive is limited, the teams gain a hell of a lot.

Craig, Bristol, via text on 81111: "If Bahrain is unworkable I say F1 should cancel and use an existing classic track like Magny-Cours, Brands Hatch or one of the German circuits they alternate between. They have existing facilities in place already and, unlike Bahrain, it wouldn't be a giant bore with half empty stands. Simples! (sort of)."

1317: Schumacher and Heidfeld are the first drivers to emerge from the pits. Both men will be looking to significantly improve their times this afternoon and Heidfeld will be especially keen to get laps under his belt after a morning disrupted by Kers trouble.

Heikki Kovalainen on Twitter: "Jarno had a shunt this morning, car failure caught him out in T9 in Barcelona, same corner I shunted 2008, not nice place to go off!"

1310: The session has officially started but we're still awaiting the cars. Ten of them to be precise. Hispania have opted against testing today after completing their planned programme on Sunday, while Team Lotus have packed up for the day following Jarno Trulli's crash into a wall earlier on.

1300: Up goes the GREEN FLAG and we're back under way. The afternoon session on the final day of testing in Barcelona. Three hours for teams to test the life out of their cars as the 2011 season draws ever closer. Everyone have a nice lunch? Good. Mine did indeed consist of pasta, tomatoes and beans (I like weird concoctions) but I fell just short on the 150 baguettes challenge. Next time...

Mercedes GP on Twitter: "Lunchtime in Barcelona! Michael has completed 54 laps this morning with his quickest time currently 1:27.079."

1215: Would anyone mind if I popped off for a spot of luncheon? Apparently the Lotus staff have consumed 25kg of pasta, 100kg of meat, 150 baguettes, 10kg of tomatoes and 4kg of baked beans during the Barcelona test. Reckon I could rival them before returning to my desk at 1300 GMT?

BBC Sport's Sarah Holt in Barcelona: "Hi David, I wondered if Lee from Chesterfield would be interested to know that Jenson Button's slightly less aggressive driving style could work to his advantage in the coming campaign? This season's Pirelli tyres are degrading a lot more than last season's Bridgestones - and that is because the Italian company were asked to produce them that way to help make the races a bit more exciting. It could be a massive boost for Button, however, because the 31-year-old McLaren driver's smooth technique is more gentle on the tyres, and that means he could make them last longer than the others during the race. Anyway, hope that helps!"
You're an encyclopaedia, Holty!

Aiden, Belfast, via text on 81111: "Jenson's getting a bit of a hard time on the live text. I think he raced as well as Lewis last season. He made his mistakes during qualifying, but performed flawlessly on race day. His two DNFs were as a result of someone else's mistakes. Lewis, on the other hand, did very well in qualifying but made his mistakes on race day. If you remove the problems caused for both by other people, the points say they were practically equal. Their very different approaches to racing mean when one struggles the other usually excels, which is why McLaren have the best driver line up on the grid."

1200: Out comes the chequered flag to signify lunch. Mark Webber has set the fastest time so far with a lap of one minute, 23.442 seconds. Sebastien Buemi (1:23.55) is second, Pastor Maldonado (1:24.057) third, Adrian Sutil (1:24.226) fourth and Felipe Massa (1:24.929) fifth. Then comes Lewis Hamilton with a time of one minute, 25.095 seconds and he's followed by Nick Heidfeld (1:26.203), Sergio Perez (1:26.914), Michael Schumacher (1:27.079), Jarno Trulli (1:29.992) and Jerome D'Ambrosio (1:31.713).

1157: Staying with McLaren, Hamilton has finally improved on the time that got him to the head of the timesheets at the start of the day. He slipped right down the pecking order during his long stint but a 1:25.094 has fired the Englishman up to sixth. Meanwhile, Massa has just completed his 63rd lap, drawing level with Hamilton at the top of the charts.

1155: Nothing like contrasting views from fans of the same team. This is what following sport is all about. Sort of.

Lee Broadent, Chesterfield, via text on 81111: "I wish Jenson Button would realise that it's not the car that's at fault but the driver. How many times did we see Lewis ring the neck of the car last season and produce a half-decent time in qualifying, while all Jenson could do was complain about a lack of grip at the rear or the front understeering? From what I've seen of the test sessions so far this season it looks like its going to be the same story!!!"

John, Surrey, via text on 81111: "I am actually encouraged by McLaren so far. They have what is essentially a totally new design and had less testing time, yet Hamilton is ticking away nicely on those long stints. So much data must be going into that McLaren garage. Watch this space!"

1149: Renault also reported a problem with their Kers this morning but Nick Heidfeld is now out on the track trying to get some running under his belt before lunch. Lest we forget, Kers (kinetic energy recovery systems) returns for the 2011 season after a one-year absence. Drivers use the systems to boost overtaking - they take waste energy from the brakes and turn it into a power boost at the push of a button.

BBC F1 pit lane reporter Ted Kravitz in Barcelona: "A little problem for Michael Schumacher. He he went out for a run but came in immediately at the end of the out lap with what looked to be a problem with the Kers. The Mercedes mechanics had to stand around in the pit lane for 20 seconds waiting to be given the all-clear that the car was safe to touch. He was wheeled back while Mercedes worked to fix the problem. After 10 minutes in the garage, Schumacher is out again."

BBC F1 commentator Martin Brundle on Twitter: "Never ceases to amaze me how much total trust the mechanics put in the drivers during a pit stop. The 2011 cars look beautiful, sound great."

1140: As mentioned earlier, McLaren will be pleased with the amount of running they've managed today. Hamilton has done more laps than anyone else - 59 - with Massa on 52, Schumacher 44, Perez 42, Buemi 43, Maldonado 33, Sutil 29, D'Ambrosio 27, Webber 24, Trulli 18, Heidfeld 7. Meanwhile, Maldonado goes third-fastest with a 1:24.057 in his Williams FW33.

1130: Half an hour until lunch at the at the Circuit de Catalunya. Webber's 1:23.442 remains the time to beat, Buemi 0.108 seconds back and Sutil 0.784 off the pace. Maldonado (1:24.745) is fourth-fastest, Massa (1:25.676) fifth and Heidfeld (1:26.630) has clawed his way up to sixth. That pushes Perez (1:26.914) down to seventh, Schumacher (1:27.079) eighth and Hamilton (1:27.561) ninth. Trulli (1:29.992) and D'Ambrosio (1:31.713) complete the field.

GeorgeTuk on Twitter: "I really hope McLaren are holding something back and not going to be relying on much-vaunted "updates" of last year!"

1125: Feel kinda guilty for tucking into this calorie-filled bar of chocolate after that. Thanks, Jenson.

Jenson Button on Twitter: "Did a 23.5k run yesterday along the coast in Barcelona which was perfect after the test. Already looking forward to jumping back in the car."

BBC Sport's Sarah Holt in Barcelona: "From the tilted glass windows of the Barcelona media centre, we have the advantage of being able to peer right down onto the Red Bull as it emerges from the garage. Mark Webber took over at the top of the timings on his latest two-lap run, with a best time of 1:23.442. The Australian has just set out on another two-lap tour of the Circuit de Catalunya."

1120: Webber still leads the way after his lap of 1:23.442, with Buemi and Sutil 0.108 seconds and 0.784 seconds adrift respectively. Hamilton's now down to eighth but lap times in the 1:32s suggest the 2008 world champion is in the midst of on a long stint for McLaren.

1115: Just to confirm for those of you asking about Bahrain, F1 supremo Bernie Ecclestone is set for talks with the Gulf state's crown prince on Monday to decide whether the season-opening Grand Prix - due to be staged on 13 March - should be postponed.

Mike, analysing lap times in a truck in Barcelona, via text on 81111: "In response to John in Belfast, you can't do a compare to last year to see if teams are sandbagging as the tyres are different, temperatures much lower, and the downforce levels are lower since the removal of the double diffuser."
Mike, are you working down at the Circuit de Catalunya or do you just happen to be analysing lap times in your truck?

1105: Into the pre-lunch hour we go and Hamilton, Massa, Schumacher, Buemi and Maldonado all hit the track.

BBC Sport's Sarah Holt on Twitter: "Popped down to Williams for a cup of tea. They seemed to be playing Dizzee Rascal in there. Meanwhile, some McLaren personnel were involved in a seemingly convoluted process of packing a truck. It seemed like giant Tetris."

1100: Cometh the hour, cometh the man. Mark Webber starts his latest run with the quickest lap of the day, an effort of one minute, 23.442 seconds. The Australian jumps above long-time leader Buemi by 0.108 seconds. Sutil, Massa and Maldonado complete the top five.

1058: "At the moment nothing at all has changed since yesterday, or the day before, or the day before that," Ecclestone has told the Press Association. "Sometime, a little later on this afternoon, I shall be speaking to the crown prince, and then we can make some decisions as to exactly what we want to do." Reports suggest that if the race is called off it may slot into the calendar at a later date, potentially in between the races in Abu Dhabi and Brazil, with the latter pushed into December from its current 27 November slot. It is reported that Bahrain pays £25m to host a grand prix, plus an additional £12m to guarantee it is the first of the new season.

1055: So here's the latest on Bahrain... F1 boss Bernie Ecclestone is due to hold talks with the crown prince later on Monday over whether the season-opening Grand Prix will go ahead on 13 March. Speculation has been rife over the last 24 hours that it will be cancelled or postponed in light of the unrest across the Gulf kingdom. Ecclestone, however, appreciates the time for an answer is at hand, and is now planning to speak with Salman bin Hamad bin Isa Al Khalifa to resolve the ongoing issue.

James, Southampton, via text on 81111: "Postponement for Bahrain? Moved to when?! The calendar is pretty chock-a-blocked already!"

1045: Hamilton finishes a 44-lap stint and McLaren will be chuffed to bits. The MP4-26 wasn't ready in time for the first pre-season test in Valencia, while reliability issues limited its track time in Jerez and again in Barcelona. The Woking-based team were desperate for laps and now they've got them.

Press Association F1 correspondent Ian Parkes on Twitter: "Just spoken with Bernie. He will be speaking with crown prince later today, after which a decision will be made. Story out shortly."

1040: Here comes another little update on Bahrain...

BBC Sport's Sarah Holt in Barcelona: "It is not all doom and gloom for Team Lotus despite Jarno Trulli's excursion this morning. Trulli was sixth in Sunday's timesheets - 2.286 seconds off pacesetter Nico Rosberg. Technical director Mike Gascoyne reckons it is a sign of things to come. 'We never used to finish sixth or be anywhere near but we finished in front of a Sauber, a Force India and a Toro Rosso - and they're the teams we want to go racing with,' says Gascoyne. 'The pace of the car is significantly better. It was a lower fuel run but not qualifying levels. Jarno was positive about the car - you can always tell when he's chatty over the radio that he's feeling bullish about it. We've got a big aerodynamic package coming to the first race so there's quite a bit of time to come.'"

1036: Sebastien Buemi heads into the pits after the latest in a series of short stints. The Swiss tops the timesheets with a 1:23.550, which is 0.676 quicker than best lap of his closest challenger, Adrian Sutil of Sauber. Ferrari's Felipe Massa (1:25.676), Red Bull's Mark Webber (1:25.792) and Pastor Maldonado of Williams (1:26.635) complete the top five. Lewis Hamilton set the pace early doors for McLaren but he's on a long run at the moment so that would explain why he's only seventh-fastest with a best time of 1:27.561.

John, "doing some crazy horrible automotive HND maths in Belfast", via text on 81111: "Can you tell us what the pole lap was in Barca last year? This is just so we can have an idea of how much the teams are sandbagging."
Sure, it was Webber's 1:19.995 and secured a Red Bull one-two on the race grid

BBC F1 pit lane reporter Ted Kravitz: "Here's the latest on Bahrain. There are two issues - the test and the race. We expect to hear an official decision on whether the race goes ahead from the FIA today, if not tomorrow. Increasing suggestions point to a postponement rather than a cancellation, but let's wait to hear offiical word from the FIA. Of course, if the race isn't going to happen neither will the test and the teams will decide in a meeting at the end of today whether to stay at the Barcelona track for another test next week. It appears the Jerez track is not available and teams would rather stay in Barcelona than relocating to Valencia or Portimao."

1018: I do, however, have a slight update for you on Bahrain...

1017: Not what you want to be hearing on the final day of the penultimate pre-season test, with no news on where and when the final test is going to take place.

Team Lotus technical chief Mike Gascoyne on Twitter: "Shunt for Jarno caused by car failure, not his fault. Going to be difficult to get back out today."

1013: I bring you bad news, Lotus fans...

Matt Smith, Tonbridge, via text on 81111: "The Toro Rosso looks fast now, but will probably end up having another disappointing season, same story with Sauber last year."

1008: Further improvement for Buemi - a 1:23.806 moves the 22-year-old 1.493 seconds clear of Sutil, 1.870 of Massa and 3.077 of Webber, who is up from ninth to fourth.

Kaykas007 on Twitter: "Timesheets dropping already, time to stay glued and see if we'll get into the 1:22s"

0956: Very soon indeed - there's the GREEN FLAG and the session is up and running once more.

0955: And that's RED FLAG number two. D'Ambrosio comes to a halt at the pit exit in his Virgin. Should be back under way very soon.

Jenson Button on Twitter: "A tough 2 days of testing for me [on Friday and Saturday] in terms of reliability but it seems like that has improved as Lewis completed almost 100 laps yesterday! Good to see that we've made improvements and now we can hopefully see what this car can do!! ;-)"

0952: Any McLaren fans out there keen to hear the thoughts of Jenson Button? Coming right up...

Helen, London, via text on 81111: "I was lucky enough to be at the testing yesterday and Red Bull kept doing practice pit stops, lap after lap with no running in between at all. No other teams did this. Were they really just practising or do you think there was some other reason?"

0948: Back to the action and Buemi remains the man to beat, improving his top time to 1:24.284. Ferrari supporters will be delighted to hear Felipe Massa has shot up to second with a 1:26.281, while Perez, Hamilton and Sutil are also in the top five.

0945: For obvious reasons, it's pretty much impossible for me to answer most of your Bahrain-related questions. But do let me point you in the direction of Monday's F1 gossip column - in there we link to a story by Autosport that suggests the 12 teams will decide on Monday whether the final pre-season test will go ahead in the wake of the ongoing unrest in the Gulf State.

0940: There the GREEN FLAG and Hamilton is first back out on the Circuit de Catalunya, soon joined by Perez of Sauber.

Ferrari on Twitter: "Today's programme includes tyre comparison and set-up changes. The weather is fine with clear skies. Temperatures are still a bit cold."

BBC F1 pit lane reporter Ted Kravitz in Barcelona: "Quite a bit going on in the pit lane but not for Mark Webber, whose Red Bull is receiving a lot of work to the engine and rear suspension area. Webber is in the garage but it doesn't look like he'll be going anywhere too soon. At McLaren, the mystery of their exhaust layout seems to be clearing up thanks to some tell-tale ceramic coated heat shields on the top of the diffuser - more about this later. Felipe Massa has been practising starts for Ferrari and Jerome D'Ambrosio has been practising pit-stops for Virgin - he hasn't done any in a Formula 1 race."

0935: A quick timesheet update for you while the recovery vehicle does its stuff and we await a green flag. We have a new pace setter and it's Sebastien Buemi of Torro Rosso. Good few days it's been for them and Buemi is top of the pops with a lap of 1:26.241. Sergio Perez is 0.673 seconds further back and Lewis Hamilton (1:27.561) sits third. Adrian Sutil (1:27.618) and Michael Schumacher (1:27.924) complete the top five. Felipe Massa (1:28.117) finds himself sixth and Mark Webber (1:39.620) way off the pace in ninth.

BBC Sport's Sarah Holt in Barcelona: "Jarno Trulli bent down and had a good look at the front of his Lotus, which is nestled next to the tyre wall at Turn Eight with its front wing looking rather mis-shapen. There could be some major repair work to be done there and the Italian trudges slowly off the gravel and back to Lotus HQ. I don't know if the team will take any comfort in this but technical chief Mike Gascoyne did say the car still has the 2010 front wing on, so at least Trulli hasn't pranged a new one."

0925: We have our first RED FLAG of the day. I think there were four in Sunday's morning session so let's hope we're going the same way today. The Lotus of Jarno Trulli has gone into the gravel at Turn Eight. Here's our intrepid trackside reporter with the full details...

BBC F1 pit lane reporter Ted Kravitz in Barcelona: "The last day of a test is always a strange one; team personnel are tired after long days of running and long nights analysing data. Having completing race simulations with Sebastian Vettel and Mark Webber, Red Bull have packed up their elaborate new pit wall gantry, leaving the engineers to monitor Webber's progress from the back of the garage. Everyone else is starting to pack up too as we expect to move to another European venue for the final test instead of Bahrain."

0920: We've already established that nobody enjoys working on a Monday so why not brighten up your day by helping me out with this text commentary. You can contribute via the Twitter hashtag #BBCF1 or drop me a specific question @bbcsport_david and I'll do my best to get back to you. Not a Tweeter? Then drop a text message to 81111 (UK). Just don't tell the boss!

Adam, pretending to work in Shrewsbury, via text on 81111: "Today will be the day where McLaren come in to a league of their own. We can all wish!"
Adam, Are you pretending to work (in Shrewsbury) or pretending to work in Shrewsbury?!

0905: Blimey, where did the first hour go? Anyway, back to the action and Lewis Hamilton continues to top the timesheets with his early lap of 1:27.561. The Force India of Adrian Sutil is 0.057 seconds adrift and Michael Schumacher is third-fastest, 0.363 off the pace. Felipe Massa of Ferrari and Toro Rosso's Sebastien Buemi complete the top five. Jarno Trulli of Lotus, Sauber's Sergio Perez, Jerome D'Ambrosio of Virgin and Red Bull's Webber complete the field. Hispania are not running today after completing their planned programme on Sunday.

0857: In the same entry I touched on Robert Kubica's performance in Valencia. Just after that, the Renault driver suffered multiple fractures to his arm and leg and partially severed his hand in a horrifying rallying crash. Latest news on the popular Pole is that he is out of intensive care following a third and final operation and will now be transferred to a rehabilitation department where he is expected to remain for two weeks. He will undergo extensive physiotherapy there as he bids to regain fitness and has said he is planning to return to racing before the end of the year.

0850: Now, at 0820 I mentioned that this was the third of four "planned" pre-season test events. The fourth - along with the first race on the calendar - is due to take place in Bahrain. As most of you know, the Gulf state is experiencing serious internal unrest at present and, understandably, there are big question marks hanging over both of the aforementioned F1 events. The sport's boss Bernie Ecclestone told BBC Sport on Sunday that he will leave the decision on whether to hold the Grand Prix in Bahrain to the country's crown prince. Later in the day, Red Bull's Mark Webber became the first driver to publically express doubts about whether the race should go ahead.

BBC Sport's Sarah Holt in Barcelona: "Hello again. It is a lovely day at the Circuit de Catalunya for the final stint of the penultimate pre-season test. The sun is out and the thermometer is creeping up towards 7C. As home to the Spanish Grand Prix, this demanding circuit is a very good gauge for the teams as to just where they are in terms of performance and reliability. Some teams feel they have more to do than others and McLaren's Lewis Hamilton was adamant that he wanted to put the hammer down after a "not particularly exciting" day of running on Sunday. For those of you off work because of half-term, here is a good chance to get those whippersnappers up to speed with a spot of Formula 1 testing wouldn't you say?"

0837: Webber, Massa and Schumancher have laid down early times too, but Hamilton still leads the way.

0835: Mark Webber, Lewis Hamilton, Felipe Massa and Michael Schumacher are among the drivers in action today and it's Hamilton who gets the first timed lap under his belt, an effort of one minute, 27.561 seconds. For purposes of comparison, Rosberg was the fastest man on Sunday with a 1:23.16 - but it's a solid start from McLaren nonetheless.

0830: Overnight rain meant a rather wet start on both Friday and Sunday, but I'm delighted to inform you the sun is out in Catalonia this merry morning and although we've got another chilly start, temperatures are expected to rise to around 15 degrees Celsius by mid-afternoon. Too late to book a flight?

Team Lotus technical chief Mike Gascoyne on Twitter: "Morning from the paddock in Barcelona, weather looks good and all ready to go."

0820: For those of you new to this lark, Barcelona is the third of four planned test events before the scheduled season-opening Bahrain Grand Prix on 13 March. Renault driver Robert Kubica set the pace in Valencia before Williams veteran Rubens Barrichello took the spoils in Jerez. Red Bull's reigning world champion Sebastian Vettel was quickest on Friday and Saturday at the Circuit de Catalunya, while Nico Rosberg of Mercedes headed the timesheets on Sunday.

0810: And that, my friends, is where Formula 1 steps into the breach. It's the fourth and final day of the pre-season test in Barcelona. Nine hours of high-speed action involving some of the world's finest drivers to help lift the Monday blues. Enjoy the ride.

0805: Monday, I'm sure you'll agree, is the most unpopular day of the working week. The fun and games of last weekend are over, the horrible wait for next weekend has only just begun. What you'd do for a day-long sporting event to alleviate the misery...