Ahead of today's sole free practice session, the air temperature is 28 degrees C, and the track temperature is 38 degrees. It is bright and sunny, and humidity is 70%.

The main news this morning is that the Red Bulls are running, the Milton Keynes outfit having convinced the FIA's technical delegate, and thereby the Race Stewards, that the RB4 is safe. However, the stewards have confirmed that the matter will be kept under review.

The lights go green, and Fisichella leads the way, followed by Sutil, Glock, Kovalainen, Trulli, Kubica, Rosberg and a whole load of others including the Ferraris and the Red Bulls.

Even though it's an installation lap, Alonso goes wide, as Hamilton, sitting in his car in the McLaren garage, points out. There was rain overnight, but it appeared to have dried out - in this heat it doesn't have much chance of doing anything else.

Having been spotted comparing notes with Williams yesterday, today a Ferrari engineer is comparing info with a Renault colleague, watched by a Williams man. Meanwhile, Bernie Ecclestone walks down the pitlane.

Ten minutes into the session, with the Hondas the only cars yet to go out, Timo Glock is the first driver to go out again. As the German heads down the pitlane, he is followed by Button and Barrichello.

Glock posts the first time of the day, the Toyota driver crossing the line at 1:39.594. Trulli, Kubica, Bourdais and Sato are back on track.

Trulli takes the top spot (37.882), ahead of his teammate, as Sato goes third, ahead of Button and Bourdais. However, Kubica and Heidfeld are both on hot laps.

Trulli improves with a 37.225, as Heidfeld goes second, however, moments later, both are leapfrogged by Kubica who posts a 37.117.

Trulli and Heidfeld re-take first and second, but already Rosberg is on a strong lap, having gone quickest in the first sector. The Williams start finally crosses the line at 36.712 to take the top spot, having gone quickest in the final sector also.

All eyes on Raikkonen, who goes quickest in the first two sectors, finally crossing the line at 35.886. As Massa takes second (36.354), Kovalainen - who was quickest in the second sector, gets it all wrong in the third, and can only manage fourteenth.

Next time around, Kovalainen goes tenth (37.099), as Raikkonen consolidates top spot with 35.729. Meanwhile, that boy Vettel goes fourth, ahead of Piquet. Massa, who has already improved, but remains second, goes quickest in the final two sectors, crossing the line at 35.663 to go quickest.

Both Red Bulls are on track, Coulthard going seventeenth as he gives the kerbs a wide berth, and Webber subsequently going third (yes third!) with a 36.383, demoting Piquet, who had just posted a 36.416. Next time around, the Renault number two re-takes third spot from the Australian.

As Bourdais goes twelfth (37.038), still no times from Davidson or Hamilton, though both are now on track. A 36.232 sees Nakajima go third, as Bourdais heads back to the pits.

At half-time, it's: Massa, Raikkonen, Nakajima, Piquet, Webber, Rosberg, Vettel, Trulli, Fisichella and Button.

Hamilton carries too much speed into one of the corners and goes wide, however, he is able to continue. Next time around there are no mistakes and the Englishman goes sixth (36.362), before being demoted when Vettel goes third.

Alonso, Button and Sutil all appear to be on good laps, as Raikkonen goes quickest in the first sector. The Finn fails to improve, However, Coulthard, who had little running yesterday, goes fourth with a 36.179. Great stuff from the flying Scot (think about it!).

Massa further consolidates the top spot with a 35.388, as we see a replay of Vettel going cross-country.

With seventeen minutes remaining, the Ferraris occupy the two top places, while the McLarens are eighth and twelfth. Even the BMWs are eleventh and seventeenth.

Glock is now on track on the medium compound as the session moves into it final, faster, phase. It has the makings of a good lap until he gets it wrong as the start of the back straight, nonetheless, he moves up to fifth with a 35.932.

Webber (hard) goes quickest in the middle sector, improving to third overall with a 35.631. Heidfeld and Alonso are down in nineteenth and twentieth.

Button (medium) goes fifth, ahead of Vettel, as Hamilton improves to seventh with a 35.927. The Englishman is on the harder compound.

Ten minutes remaining, and the order is; Massa, Raikkonen, Webber, Piquet, Button, Vettel, Hamilton, Glock, Coulthard and Nakajima.