Ahead of today's all-important qualifying session, the air temperature is 23 degrees C while the track temperature is 31 degrees. It is bright and sunny, not at all what was expected.

Lewis Hamilton was quickest this morning, however, Red Bull's Mark Webber ran him close. Over the course of the three sessions it's been pretty evenly matched, however, it is clear that the Mercedes powered cars - and let's not forget the works team and Force India - will be strong here.

That said, there are two big question marks. One concerns the weather, with rain expected at some stage tomorrow afternoon, while the other relates to tyre degradation.

While the super-softs (option) were always expected to go off quite quickly, no-one expected them to degrade quite as quickly as they are, sometimes after only a couple of laps. Furthermore, the prime tyres are degrading also, leading to speculation that some drivers will need to pit twice tomorrow. Indeed, there is speculation that with an eye on tomorrow's race - certainly the opening stint - drivers might opt to rely on the prime tyre this afternoon.

Of course, all this talk of degradation will go out the window if the heavens do open up tomorrow afternoon.

Other than the Red Bull/McLaren saga, Mercedes is looking better here this weekend as are Ferrari and Red Bull. Force India continues to impress as do Sauber, while Williams and Toro Rosso have both looked a little wobbly thus far this weekend.

Of the new teams, Lotus continues to lead the way though Jarno Trulli has had a torrid weekend thus far. Yesterday, Hispania appeared to have the edge over Virgin, however, today the order seems to have been reversed.

The lights go green and Glock is first out of the gates, followed, shortly after, by Petrov, Trulli and Glock. Chandhok, who only managed the length of the pitlane this morning, is another driver eager to get out and get to work.

Petrov posts 20.210 as Kovalainen goes second ahead of Glock, Trulli and di Grassi. Virgin boss grins inanely at the monitor on the pitwall. A big lock up for Petrov which won't due the Russian any favours.

Five minutes into the session, all but Massa and Kubica are on track as Sutil goes quickest (18.143) only to be demoted by Petrov.

Alonso posts 17.864 as Hulkenberg goes fourth and Barrichello ninth. However, all eyes are on Webber who is running on the option tyre. The Australian posts 17.988 to go fifth as Button and Hamilton - both on options - begin their first flying laps.

The order is constantly changing, for a brief moments Alonso and Massa are first and second only to be eclipsed by Petrov and then Webber (17.102).

Hamilton posts 16.614 to take the top spot form Liuzzi, the order changing constantly. Vettel pos up in second and Button third as Webber goes quickest in the second sector. The Australian posts 16.423 to go second to Alonso… yes it's happening that quickly.

As Hamilton posts 15.889, all the usual suspects are at the bottom of the timesheets with no major surprises. That said, there are eight minutes remaining. Hamilton, Vettel, Alonso, Button, Webber and Sutil.