So it took them a while, but at least they got there in the end.

HRT did manage to get most of their car through the FIA's stringent crash tests - which must be passed before a car can hit the track for testing or in a race weekend - but kept stumbling at the final hurdle thanks to a problem with the rollhoop test.

The Spanish team ran last year's car for two days in Jerez, as they wanted the influx of new employees to get experience of working together. The original plan had been to run the 2012 car for the first time in Barcelona last week, but had to pull out when they failed the final crash tests.

But while HRT have finally passed the crash tests, there's still no guarantee we'll see them at the Circuit de Catalunya next week. The car still needs to be assembled and shipped to Barcelona, and no one's confident the team will make it in time.

[Disclaimer]: I'm not actually in Barcelona; this coverage has been supplied via live updates, team releases, and the like.

While Kamui Kobayashi set the fastest time of the first week of the Barcelona test, the Japanese driver has no delusions about the timesheet’s effect on the 2012 F1 championship.

“It's better than nothing, better than last for sure,” Kobayashi told the press after the day’s running was completed. “I don't think this is a real result and I know more than anybody about this situation. I don't think the McLaren and Red Bull are so slow.”

In addition to topping the timesheets this afternoon the Sauber driver also led the number of laps completed, with an impressive 145 under his belt by the time the chequered flag fell. Joining Kobayashi at the top of that leaderboard were Nico Robserg, who passed the start/finish line 139 times in his W03, and Pastor Maldonado, who managed 134 laps for Williams.

Ferrari, who have been the subject of much criticism over the course of the Jerez and Barcelona tests (including on these pages) appear to have turned a performance corner this week. Speaking to reporters after the session ended, Felipe Massa spoke of his enthusiasm for the work done by the team.

“I think it's definitely the direction we need to follow for these last days of testing we have, and I think today was a positive day, not so much in the morning but in the afternoon,” the Brazilian driver said. “I have to say that now we are a little bit more positive because we found the direction to work and I'm sure now, having found the direction, we can see the development coming.

“In the afternoon we were able to do more than eight/nine timed laps consistently. The laps were very consistent and it was very positive. We still need to work a lot but at least we found the direction to get a much better car to drive, not just for laptime for also for consistency.”

The session was light on incident but high on problems, with a number of teams losing out on track time thanks to a variety of issues.

Worst affected of the lot was Marussia, who were unable to complete a single timed lap thanks to a damaged suspension component. The team spotted the problem at the right rear of the car before sending Charles Pic out on track this morning. While there was a spare available, the nature of the component failure was such that both the damaged piece and its spare were not suitable for use until they had passed extensive testing back at home base.

Marussia can now concentrate on the launch of their 2012 challenger, which is due to be unveiled last week.

“It's a real shame that after three very positive days with the car we've encountered this issue on the final day,” said team principal John Booth. “We can't be too downhearted though, having achieved over 1500kms of near faultless running from a car that has served us so well from a reliability perspective. Aside from further mileage for Charles there was nothing more to be gained from our programme to aid our development and we now switch focus to the 2012 car, which we are all looking forward to rolling-out next week.”

Heikki Kovalainen lost out on time behind the wheel of the Caterham thanks to an electrical problem that led to an engine change early in the day. The team worked hard to get the Finn back out on track, and he was eventually able to complete 70 laps without further incident.

There were three red flags over the course of the day’s testing, although the final two were brought about by McLaren and Sauber running their fuel tanks dry in the final fifteen minutes. The only red flag caused by on track activity came about thanks to Paul di Resta, who beached his Force India at the outside of Campsa before the lunch break.

The rest of the day’s running was largely unremarkable, with no moments of spectacular drama – good or bad – for any of the teams. Today marked the end of the second week of winter testing; Formula 1 will return to the Circuit de Catalunya next week for the final pre-season test.

Day 4 times (unofficial)

1. Kamui Kobayashi (Sauber) 1.22.312s [145 laps]
2. Pastor Maldonado (Williams) 1.22.561s [134 laps]

3. Paul di Resta (Force India) 1.23.119s [101 laps]

4. Jenson Button (McLaren) 1.23.200s [115 laps]

5. Felipe Massa (Ferrari) 1.23.563s [103 laps]

6. Mark Webber (Red Bull) 1.23.774s [85 laps]

7. Jean-Eric Vergne (Toro Rosso) 1.23.792s [92 laps]

8. Nico Rosberg (Mercedes) 1.23.843s [139 laps]

9. Heikki Kovalainen (Caterham) 1.26.968s [70 laps]

[Disclaimer]: I'm not actually in Barcelona; this coverage has been supplied via live updates, team releases, and the like.

A headline-grabbing lap set in the late morning put Pastor Maldonado top of the timesheets at the end of the third day’s testing in Barcelona.

The Williams driver completed 106 laps over the course of the day’s running, and his 1.22.391s lap made the Venezuelan the only man to set a time in the 1m22s.

As was the case yesterday, long runs and race simulations were the popular choice in the afternoon, as teams begin to work on getting the cars ready for the season ahead, as opposed to merely getting the cars up and running. Different to yesterday were the men behind the wheel, the majority of whom took over from their teammates this morning to complete the second half of the first Barcelona test.

Maldonado, Kobayashi, Jenson Button, Jean-Eric Vergne, Mark Webber, Felipe Massa, Paul di Resta, and Timo Glock all made their 2012 Barcelona debuts this morning.

Thursday saw a number of red flags, with the session ending early as a result of a stoppage by Massa, who stopped his F2012 at the end of the pit lane when he ran out of fuel. Ferrari were conducting a ‘how low can you go’ fuel test typical of winter testing.

Webber brought out a red flag with half an hour of the session remaining, with the RB running out of steam at Turn 8. The Australian driver also suffered reduced track time as the result of a gearbox problem. After the day’s running drew to a close it was rumoured that Red Bull would be withdrawing from the final day of testing in order to concentrate on problems related to Webber’s stopping on track, although they have yet to be confirmed.

Webber’s was the fourth red flag of the day. The first came thanks to Paul di Resta, who saw the engine cover fly off his VJM05 in the late morning. Then Timo Glock brought out the red flags when he span his Marussia, before Kamui Kobayashi caused an early lunch break – by three whole minutes – when he stopped at Turn 4 having run out of fuel.

The high number of red flags were only one sign of a troublesome day’s testing. Vitaly Petrov struggled to find the ideal set-up in only his second day in the Caterham; the Russian’s efforts were further hampered by problems with his front suspension. In addition to their flying bodywork, Force India also lost some running time as they fine-tuned the mechanical and aerodynamic balance of the VJM05.

Mercedes were able to complete a full race distance in Barcelona today, an impressive feat for a car that saw its first real running only four days ago.

Day 3 times (unofficial)

1. Pastor Maldonado (Williams) 1.22.391s [106 laps]
2. Michael Schumacher (Mercedes) 1.23.384s [127 laps]
3. Kamui Kobayashi (Sauber) 1.23.582s [99 laps]
4. Jenson Button (McLaren) 1.23.918s [114 laps]
5. Jean-Eric Vergne (Toro Rosso) 1.24.433s [78 laps]
6. Mark Webber (Red Bull) 1.24.771s [97 laps]
7. Felipe Massa (Ferrari) 1.24.771s [84 laps]
8. Paul di Resta (Force India) 1.25.646s [83 laps]
9. Timo Glock (Marussia) 1.26.173s [108 laps]
10. Vitaly Petrov (Caterham) 1.26.448s [70 laps]

As predicted on this website two days ago, Lotus are almost certain to be granted one day of extra testing to make up for the three days lost this week.

In order to qualify for an extra day Lotus must get unanimous consent from their fellow teams. The consent has been applied for, and while there has yet to be official confirmation that the Enstone team can reclaim some lost track time it is expected to be granted later today.

The Mercedes F1 team have already run a one-day private testing after choosing to run for only three days in Jerez. As the teams allowed the Silver Arrows some private track time, Lotus are expected to be treated with similar leniency.

While any additional track time will be a benefit, Lotus will still suffer the consequences of the chassis problem as noise controls around the Circuit de Catalunya mean that running time in Barcelona is strictly regulated and includes mandatory lunch breaks.

Any extra day will therefore see the team run for a maximum of eight hours (assuming no mechanical or reliability issues).

While there's not a huge amount that can be learned from winter testing, reliability is one thing you can depend on.

That wasn't phrased well, but at least I avoided the obvious pun on reliable.

Anyway. Whatever you do to mask your true pace, you can't hide the number of miles you've got under your belt, be they good or bad. You also can't mask bits falling off the car as you make your way around the track, or regular red flags.

Lotus had to go very public with their reliability concerns last night, when the Enstone-based team took the highly unusual decision to withdraw from the last three days of the first Barcelona test.

Where it first appeared that the team had to suffer the inconvenience of one faulty chassis, further tests back at the factory have established that both chassis 1 and 2 require investigation and likely moderation before they can be used again.

Lotus have remained tight-lipped about the precise nature of the chassis problem, but given that the team have not been able to patch the car together so that it is suitable for safe running and general data-harvesting there is no doubt that it is serious.

There has been much speculation that the high lateral loads placed on the car by the Circuit de Catalunya's high-speed corners has exacerbated an existing weakness in the chassis, possibly in relation to the engine mounts.

Whatever the precise source of the problem there's no doubt that all hands are now on deck at Enstone. Losing time in winter testing is a pain, losing development time on Melbourne-spec kit is also a pain, but to suffer both of those indignities while using equipment to fix your chassis is a form of agony.

[Disclaimer]: I'm not actually in Barcelona; this coverage has been supplied via live updates, team releases, and the like.

Nico Hulkenberg was the fastest man of the day in Barcelona, and topped the timesheets with an impressive 112 laps under his belt.

The German driver crossed the line in 1.22.608s in the late morning, dethroning fellow countryman Sebastian Vettel. Hulkenberg’s time stood largely unchallenged for much of the day, as teams concentrated on longer runs and race simulations when possible.

Both Vettel and Lewis Hamilton completed what appeared to be full race simulations over the course of the day, with the McLaren driver taking the top spot in the miles run chart with 120 laps under his belt. The Red Bull and McLaren looked to be closely matched on the longer runs, although Vettel didn’t have much trouble getting past Hamilton when he put his mind to it.

Sergio Perez finished the day in P2 on the timesheets with a respectable 85 laps under his belt. While Perez is certainly fast, today’s pace may have more to do with the sheets of white space on the side of the C31 than the car’s genuine ability to challenge for the championship.

One driver to have a more difficult time of it was Toro Rosso’s Daniel Ricciardo. The Australian stopped out on track after a driveshaft failure, and spent his time on track concentrating on shorter runs.

“The afternoon did not go to plan,” Ricciardo said. “But the morning was positive and we did all the runs we had planned for the first part of the day. We worked on making adjustments to the car balance, also trying some different mechanical changes to the car, which is why I did mainly short runs. I could feel the effect of these changes and the car reacted in the way we expected.”

Vitaly Petrov made his debut for Caterham at the Circuit de Catalunya today, and despite a few early hiccups the Russian driver was satisfied with the day’s work.

“I think that was a pretty positive day,” Petrov said. “We completed 69 laps and got through most of what we had planned. This morning we had a couple of issues with the seating position and the brakes, but you expect that from a new car and they were little things that we were able to fix quickly. In the afternoon we put in a few more long runs and that'll give us a lot of data to work on tonight and I think tomorrow it will be more of the same.”

Fernando Alonso was one of a small group of drivers to improve in the afternoon, although the changes were marginal. Joining the Ferrari driver in the afternoon improvement club were Charles Pic and Valtteri Bottas, fresh(ish) faces in the F1 paddock.

Alonso has a lot of pressure on his shoulders as Ferrari’s star driver. Whatever the F2012 eventually proves itself capable of, the tifosi will expect wins. At the moment, it looks as though the Spanish driver will have something of a challenge on his hands, but – as Alonso said in his post-session comments – what counts is where you are after Q3 in Melbourne, not on a Wednesday evening in Barcelona.

Lotus did not run today, and will not run for the remainder of this week’s session. The Enstone-based team withdrew from the test yesterday evening when it transpired there was serious work to be done on their chassis before testing could continue.

Day 2 times (unofficial)

1. Nico Hulkenberg (Force India) 1.22.608s [112 laps]
2. Sergio Perez (Sauber) 1.22.648s [85 laps]
3. Sebastian Vettel (Red Bull) 1.22.891s [104 laps]
4. Fernando Alonso (Ferrari) 1.23.180s [87 laps]
5. Daniel Ricciardo (Toro Rosso) 1.23.639s [48 laps]
6. Lewis Hamilton (McLaren) 1.23.806s [120 laps]
7. Nico Rosberg (Mercedes) 1.24.555s [82 laps]
8. Valtteri Bottas (Williams) 1.25.738s [117 laps]
9. Vitaly Petrov (Caterham) 1.26.605s [69 laps]
10. Charles Pic (Marussia) 1.27.343s [108 laps]

It's been well-documented that Lotus had issues with their chassis in Barcelona this morning.

But where an hour ago we thought that the Enstone team would carry on testing with a different chassis as of tomorrow, having lost out on serious running time today, Lotus have since announced that they will be withdrawing from the first Barcelona test with immediate effect.

"Before we were due to fly chassis E20-01 out to Barcelona in replacement of chassis E20-02 - damaged this morning - we ran a series of simulations at the factory based on the data provided by our brief running on track today," Autosport quote technical director James Allison as saying.

"As a result, we were able to identify an area which requires some additional work. It will be more productive for us to carry out these modifications to both chassis at Enstone rather than send E20-01 out to this week's test. We'll put the right measures in place and we will be able to fix the problem before next week."

Team principal Eric Boullier told Autosport: "Not running this week has been a tough decision to take, but we feel that our choice is the right one. On the positive side, we have quickly identified the issue with the chassis and our design office has already devised a solution. We will be present at next week's test in Barcelona.

"We draw faith from the fact that the E20 was quick out of the box in Jerez and showed its reliability there. We have a lot of work ahead of us over the next week but everyone at Enstone is ready for this challenge."

While team officials sound confident that the chassis problem is only a minor setback, there is little doubt that the powers that be are more concerned than they are letting on.

The problem with the chassis may well be under control, but three days of lost track time in the run-up to the season is highly likely to see the team on the back foot relative to the opposition.

Lotus should be able to reclaim at least one day for a private test before or after the final Barcelona test.

[Disclaimer]: I'm not actually in Barcelona; this coverage has been supplied via live updates, team releases, and the like.

It was a busy day for Marussia rookie Charles Pic, who completed 121 laps of the Circuit de Catalunya during his first day behind the wheel.

Lewis Hamilton had a similarly rubber-busting day in the McLaren, with 114 laps under his belt. The British driver spent the day working on a series of race simulations for the team, with the MP4-27 proving itself to be as reliable in Barcelona as it appeared to be in Jerez.

With nine laps under his belt, Caterham's Heikki Kovalainen stopped at the last corner thanks to a suspension failure it took the team much of the day to fix. The Finn was able to get back out on track in the afternoon to complete just over 20 more laps, but there is no denying that the loss of valuable testing time will have been a great blow to the team.

Over at Sauber Sergio Perez saw his day affected by a problem with the rear anti-roll bar which meant the Mexican racer was only able to complete 66 laps behind the wheel of the C31.

"We obviously didn’t cover the mileage we wanted to today, but such things happen in testing," head of track engineering Giampaolo Dall’Ara explained. "In the morning we had some doubts related to the structure, which didn’t occur in Jerez and therefore appear to be track related. It is important to discover something like this during testing instead of at a grand prix weekend. We touched base with our experts in Hinwil for analyses and at the same time found a mechanical solution here at the track. In the afternoon we then had another unforeseen break due to a mechanical issue with a rear anti roll bar. Not actually a big issue, but quite time consuming as the gear box had to be removed again, etc. So now we will concentrate on our test programme for tomorrow and hope for a rather smoother session then."

Another team to suffer the effects of lost running today was Lotus. Trackside operations director Alan Permane explains: "This morning was our first shakedown of our second chassis. Once the car was on track it was soon evident that everything wasn’t quite as it should be. As a precaution we are returning the chassis to Enstone for further investigation. Chassis E20-01, which we used in Jerez, is being sent over and we expect to be on track with that chassis tomorrow."

But without a doubt the team most affected by lost track time in the run-up to the 2012 Formula 1 season getting underway in Melbourne in less than four weeks' time is HRT.

The Spanish outfit will not be allowed to run this year's car on track in either testing or race conditions until they have passed the full gamut of FIA crash tests. While the majority have run without a hitch, HRT are believed to have failed two tests twice apiece.

Ferrari, Mercedes, and Williams all had fairly unremarkable days, with no major issues but no glories either. It was the first day of public running for Mercedes, who officially unveiled the W03 in the pitlane this morning.

Both Force India and Toro Rosso should be singled out for their respectable performances today. Nico Hulkenberg managed 97 laps and finished the day second in the timesheets, while Daniel Ricciardo ended the afternoon in P4 with 76 laps under his belt.

Top of the timesheets at the end of the day was Red Bull's Sebastian Vettel, a sign that some have chosen to read as ominous. That it may well be, but there's still no point trying to read too much into the times set in testing.

Day 1 times (unofficial)

1. Sebastian Vettel (Red Bull) 1.23.265s [79 laps]
2. Nico Hulkenberg (Force India) 1.23.440s [97 laps]
3. Lewis Hamilton (McLaren) 1.23.590s [114 laps]
4. Daniel Ricciardo (Toro Rosso) 1.23.618s [76 laps]
5. Fernando Alonso (Ferrari) 1.24.100s [75 laps]
6. Michael Schumacher (Mercedes) 1.24.150s [51 laps]
7. Sergio Perez (Sauber) 1.24.219s [66 laps]
8. Bruno Senna (Williams) 1.25.711s [97 laps]
9. Heikki Kovalainen (Caterham) 1.26.035s [31 laps]
10. Romain Grosjean (Lotus) 1.26.809s [7 laps]
11. Charles Pic (Marussia) 1.28.026s [121 laps]

Chassis
Construction Moulded carbon fibre and honeycomb composite structure
Suspension Wishbone and pushrod/pullrod activated torsion springs and rockers
Dampers Penske
Wheels BBS forged magnesium
Tyres Pirelli
Brakes Brembo calipers
Brake discs/pads Carbon/Carbon
Steering Power assisted rack and pinion
Steering wheel Carbon fibre construction
Electronics FIA standard ECU and FIA homologated electronic and electrical system

Transmission
Gearbox Seven speed unit with cast aluminium maincase
Gear selection Sequential, semi-automatic, hydraulic activation
Clutch Carbon plate

Dimensions
Overall length 4800mm
Overall height 950mm
Overall width 1800mm

Engine
Type Mercedes-Benz FO108Z
Capacity 2.4 litres
Cylinders 8
Maximum rpm 18,000 (maximum FIA regulation)
Bank angle 90°
Piston bore 98mm (maximum FIA regulation)
No of valves 32
Weight 95kg (minimum FIA regulation weight)

The launch of the MGP W03 would have been improved by the presence of cake. Not that I was there, mind - I'm not in Barcelona this week - but everything in life is improved by the presence of cake.

At this point in the pre-season I have launch fatigue. If teams are going to show off their new cars by wheeling them out into the pitlane for a bit then what is there to get excited about? Especially when - as is the case with Mercedes - we've all seen photos of the car anyway.

I say stuff the credit crunch. Who needs to be in touch with financial reality when there's the possibility of launching cars in space, or flying journalists to a tropical island on the backs of pegasuses (pegasi?) to feed us with rum until we think the platypus nose isn't too bad after all, and as long as our mates aren't looking we might just wind up going back to her place, and...

Sorry, lost my train of thought there. TL/DR? Credit crunch car launches are dull.

The Mercedes launch was supposed to be vaguely exciting in that it's the car we've all been waiting for. First off, it's the only front-running candidate we'd not seen yet (can you feel the tension?), and secondly it's the car everyone's been trying very hard to convince us is this year's Red Bull beater.

And if an excess of technical directors is what it takes to defeat the mighty pencil of Adrian Newey, then Mercedes are in with a decent shot.

Which isn't to say that the car doesn't have a few features worth waiting for Scarbs to analyse. The most interesting - and obvious - is the lozenge on the nose, which is used to direct the flow of air around the front of the car. People have been referring to it as the Mercedes F-duct, and while that doesn't make sense to me, who am I to buck a trend?