Ahead of today's sole free practice session, the air temperature is 31 degrees C, while the track temperature is 35 degrees. It is 19:00 local time and the humidity is 67%.

With yesterday's first session reduced to sixty minutes due to problems with the kerb and then Sebastien Buemi's off, we had to really on the second session to give us a better picture.

Sadly, depending on your point of view, it was a familiar picture, Sebastian Vettel leading the way. While the German refuses to concede that the title is all but won, as we reported earlier he is clearly leaving nothing to chance, working with his team until 5am this morning, a couple of hours after the equally industrious Michael Schumacher had left.

Fernando Alonso was second quickest overall, ahead of Hamilton, Massa and Webber.

These five were covered by 0.891s, with sixth quickest Schumacher a further 1.2s behind.

If you're wondering about Button, the Englishman would have been up there but was sidelined when a gearbox problem meant he was unable to get reverse after locking up and nearly hitting the barriers.

Other than the weather - rain is predicted both today and tomorrow - and those pesky kerbs, the topic on everyone's lips is tyres, with degradation a real problem here. That said, whereas McLaren admits it is struggling, Ferrari claims to be more confident.

While Renault has dropped much of the bodywork upgrade package it ran yesterday, McLaren is running new wings on both cars.

When the lights go green d'Ambrosio leads the way, followed by Alguersuari, Glock, Ricciardo, Perez, Kovalainen, Buemi and Liuzzi.

Within moments all but the Red Bulls, Button and Sutil are on track. Senna locks up and takes to one of the generous run-offs.

Five minutes into the session, Button remains the only driver yet to show, McLaren desperate to have at least one of its drivers on the front row tomorrow.

Curiously, Ferrari reveals that it will be around twenty minutes before its drivers are back on track. Meanwhile, d'Ambrosio is the first driver out for a second run. In time the Belgian is joined by Alguersuari, Glock, Buemi, Kobayashi and Hamilton.

D'Ambrosio posts the first time of the day, the Virgin driver crossing the line at 2:01.174. In the Mercedes garage a mechanic is blowing a jet of dry ice into Schumacher's gloves. The mind boggles.

As Kobayashi goes quickest in the first two sectors, Hamilton is also on a hot lap. The Sauber driver posts 52.574 while the McLaren driver can only manage 55.324.

More and more drivers pour on to the track as Kobayashi raise the bar with a 52.198. Moments later, as Hamilton improves to 54.836, Perez makes it a Sauber 1-2 with a 52.629.

On his first flying lap Button goes quickest in all three sectors, the Englishman finally crossing the line at 50.707.

Schumacher posts 51.076 to go second, the German having gone quickest overall in the first sector. Moments later, former Ferrari teammate Barrichello posts 51.834 to go third.

A 50.494 sees Rosberg go quickest, however, moments later Button slams in a 49.490 to re-take the top spot. Sutil goes fourth (51.679) ahead of Maldonado, Barrichello and di Resta.

Ferrari reports that there is a rain shower a few miles away but that it should miss the circuit.

Schumacher makes his frustration obvious when a slow Maldonado ruins his lap, the German subsequently dives into the pits.

Twenty-six minutes into the session, the Ferrari and Red Bull duos wait resolutely in their garages. Hamilton, now down in twelfth, is on a long run, probably with heavy fuel with an eye on the opening stint tomorrow. Teammate Button is the once concentrating on fast runs, the Englishman upping the ante with a 48.421 having gone quickest in all three sectors.

Bang on half-time, Alonso leave the pits, the Spaniard immediately posting a 48.937 to go second. Massa and the Red Bulls are also on track.

All times thus far posted on the harder (prime) soft tyre.