1605: So that's it. Tuesday's running is over and it's a case of as you were - with Massa fastest on one minute 11.722 seconds; Kobayashi 1m12.056; Hamilton 1m12.256; Kubica 1m12.426; Rosberg 1m12.899; Barrichello 1m13.377; Buemi 1m13.823. We'll be back on Wednesday for what should be an exciting final day, with Jenson Button taking over from Hamilton in the McLaren, Michael Schumacher back in the Mercedes and Fernando Alonso getting his first run in the (very fast looking) new Ferrari. I've got goose bumps just writing that.

1600: Robert Kubica's Renault has stopped on the pit straight and the Pole has climbed out of his car. The session has been stopped and it looks like there will not be a restart.

BBC Sport's Sarah Holt at Valencia: "Fernando Alonso has been spotted arriving at Ferrari - the great man takes over from team-mate Felipe Massa at the wheel of the F10 on Wednesday morning. Unfortunately, I can't get in at the moment as they've beefed up the security."

1531: With less than half an hour to go, we are entering what is traditionally known as "happy hour" at F1 testing, when the teams take out some fuel, fit new tyres and send their drivers out to record a quick time. Already, Autosport's Jonathan Noble on Twitter reports Renault's Robert Kubica dipping into the mid-1min 12secs bracket after a low-key test so far.

1530: Finally, Nico Rosberg noses ahead of team-mate Michael Schumacher in the battle of the Mercedes. Rosberg sets a 1:12.899 lap, which sneaks him ahead of Schumacher's 1:12.947 from Monday. Wonder how long it will take Michael to beat that on Wednesday morning?

1515: The keener F1 aficionados among you will have heard by now of the mysterious Stefan GP team, which a Serbian businessman called Zoran Stefanovich is hoping to set up. They don't have an entry for 2010 but are pressing ahead with plans which seem to revolve around taking over the design and cars of the former Toyota team. The latest news from Stefan GP is that they say on their website that they have shipped a container of equipment to Bahrain for the first race. They must know something we don't, obviously - and the word on the street is that F1 boss Bernie Ecclestone has told them to expect to race because he thinks one of the new teams will not make it.

1510: Things are pretty quiet at Valencia right now - by which I mean the cars are going round very noisily, obviously, as the teams go about their work but that there is not much to report. So it's a good opportunity to mention that we're expecting to have interviews with Lewis Hamilton and Felipe Massa on the website later this evening, so keep an eye out for those.

1445: Hamilton has improved his time to one minute 12.256 seconds even though he stays third behind Kobayashi's Sauber. Massa's Ferrari is still fastest on 1:11.722.

1420: You may remember BBC Sport's Sarah Holt mentioning earlier that Jenson Button had arrived at the track ahead of his turn in the car on Wednesday. Well, here is a picture of the world champion striding down the paddock looking very F1 with his trademark 'sunnies' tucked into his grey v-neck, and scarf blowing in the brisk Valencia breeze.

BBC Sport's Sarah Holt in Valencia: "If you are wondering about Kamui Kobayashi's super-fast time for Sauber (1:12.056) then his team-mate Pedro de la Rosa may be able to shed some light.

"The Spaniard, who is back in a race seat after seven years as a McLaren reserve, was second to Ferrari's Felipe Massa on Monday - as Kobayashi is on Tuesday.

"De la Rosa reckons the car feels good and is hopeful the team can build on the foundation put in place by former owners BMW.

"De la Rosa also revealed that it was a difficult winter for him as he waited to see if he would secure a drive in F1, and now he's excited to be back.

"The 38-year-old also mentioned that he might not have long left - before clarifying he meant in his racing career and not in general. Phew! You had us worried there, Pedro."

1335: An update on where we are on fastest times with a little over two hours remaining: Massa (Ferrari) 1:11.722, Kobayashi (Sauber) 1:12.056, Hamilton (McLaren) 1:12.368, Rosberg (Mercedes) 1:12.899, Barrichello (Williams) 1:13.377, Kubica (Renault) 1:13.369, Buemi (Toro Rosso) 1:14.862. Remember, though, that the headline times don't necessarily accurately reflect the competitiveness of the cars because of varying fuel loads, although it has to be said that Massa in the Ferrari has very obviously been impressively and consistently quick for the whole test so far.

BBC Sport's Sarah Holt at Valencia on Twitter: "I think the phrase to describe lunch at Toro Rosso is 'feeding time at the zoo'. Disheartened they were out of M&Ms"

BBC Sport's Sarah Holt at Valencia: "Jenson Button has arrived at the track, sporting a grey jumper to protect him from the cold weather. The world champion has popped in and out of the McLaren garage - he's taking over the car from Lewis Hamilton in the morning. Apparently, team principal Martin Whitmarsh is due in later on Tuesday as well."

1220: Williams's Claire Williams has posted on her Twitter page a photo of the crowd at Valencia for this first pre-season test - there's a surprisingly large number of people there, which just goes to underline the massive interest in this first sight of the new F1 cars and their drivers.

1210: They've stopped for lunch at the Circuit Ricardo Tormo now, and Felipe Massa's Ferrari is still fastest with his lap of one minute 11.722 seconds. After that it's Kamui Kobayashi continuing team-mate Pedro de la Rosa's good showing on Monday in the Sauber on 1:12.056, then Lewis Hamilton's McLaren on 1:12.508, Nico Rosberg in the Mercedes on 1:12.899, Williams's Rubens Barrichello on 1:13.377, Robert Kubica's Renault on 1:13.659 and the Toro Rosso of Sebastien Buemi on 1:14.862.

1200: How's your Portuguese? "fala galera...pausa pequena pro almoço...mais tarde coloco umas fotos...abraços", Rubens Barrichello says on his Twitter page . Fortunately, he provides a translation, too: "lunch break...later I will post some pictures...cheers". Always was a nice chap, Rubens.

1140: Michael Schumacher's return to Formula 1 has grabbed much of the attention so far in Valencia. For the inside line on his first day behind the wheel of the Mercedes, read BBC Sport's Sarah Holt's blog on the subject.

BBC Sport's Sarah Holt at Valencia: "I return from my special mission at McLaren HQ with news on the 'fluminescent' paint daubed along the side of the car. First of all, the team say there is 'no cause for concern'. They have been using the paint, known as flow-viz, for periods during both days of testing but say it is completely normal and does not flag up underlying aerodynamic problems. Lewis Hamilton has returned to team HQ to say he's happy with the car this morning while test driver Gary Paffett reported back that there was a close correlation between the data coming from the simulator and the track during his running on Monday."

1125: It's worth pointing out again that all lap times from these tests should be taken with a pinch of salt - this year more than ever. It's always difficult to compare them as you never know what specification the cars are running in but with the banning of in-race refuelling this year, cars will be as much as five seconds a lap slower on full tanks at the beginning of a race than on near-empty ones at the end - and all conditions have to be simulated in testing. At the end of testing, though, we will be doing our best to cut through the fog for you.

1115: On the subject of MercyMurcia's remark below about McLaren potentially using 'fluminescent' paint again, I have the estimable Sarah Holt checking it out on the ground. If true, it does not bode well. Teams use the paint - so named because it helps them see the flow of air over the car and is luminescent - to check out what might be happening if the car is not performing as expected.

BBC Sport's Sarah Holt in Valencia: "Michael Schumacher has just emerged from his motorhome - he's not driving today - and headed off for a bike ride with his trainer. For those interested in his unique personal fashion sense, he is wearing a bright red helmet and matching top, with some black lycra shorts."

From MercyMurcia on 606: "I've just seen a pic of McLaren using the green paint! Horrible flashbacks of testing 2009 are now full swing in my mind! Does this mean there are big aero problems with the side pods?"

1050: All right, hands up who wants to see Lewis Hamilton in his new car. All of you? Right you are then.

BBC Sport's Sarah Holt in Valencia on Twitter: "Kobayashi goes second (1:12.384), Rosberg (1:12.899), Hamilton (1:13.161), Kubica (1:14.714), Buemi (1:14. 928), Barrichello (1:15.493)"

1040: Britain already has two world champions in F1 in Lewis Hamilton and Jenson Button, and the next generation looks now it is now beginning to arrive - the highly rated Scot Paul di Resta has been appointed Force India's test and reserve driver.

1035: Want to know what advice Michael Schumacher's former team-mate Rubens Barrichello has for his new one, Nico Rosberg? "Get out of there!" the Brazilian said on Monday. Catch up with all the F1 tittle-tattle in our gossip column .

1030: BREAKING NEWS - The Formula 1 Commission, the sport's rule-making body, has voted to change the points system for the second time in two months. It has extended the gap from first to second place to seven points rather than five in an attempt to encourage drivers to race to win (as if they don't already), so the top 10 now goes: 25-18-15-12-10-8-6-4-2-1. A full news story will follow shortly.

1015: Massa is taking up where he left off on Monday with some scintillating lap times - after the first hour of testing the Ferrari is down to one minute 11.722 seconds, which is the first sub-1:12 lap in testing so far this winter. Hamilton's best so far in the McLaren is a 1:13.161.

0945: In an unexpected change, Felipe Massa will continue in the Ferrari on Tuesday, with new team-mate Fernando Alonso taking over for the final day on Wednesday.

BBC Sport's Sarah Holt in Valencia: "It's a much chillier start to the day in sunny Valencia - only 9C outside and 20C on the track, which means you may have to stick around to see the fastest times of the day.

"Things are hotting up on the track as the second world champion on the 2010 grid, Lewis Hamilton, is out and about for McLaren. He has a best of 1:31.161 so far which is already better than reserve driver Gary Paffett's best time of 1:13.846 on Monday.

"Ferrari's Felipe Massa is still leading the pack after banging in more than 20 laps already. It may not all be about speed on day two, however.

"The teams are expected to experiment with heavy and light fuel loads to prepare for this season's ban on refuelling. It's likely to be qualifying light and race heavy, so the teams need to trial those differing strategies over the next four tests."

0930: Morning all. The second day of testing at Valencia is under way and many eyes will be on Lewis Hamilton, who is testing the new McLaren for the first time.