Ahead of today's practice session the air temperature is 12 degrees C, while the track temperature is 20 degrees. Currently it is bright, though there are some ominous clouds in the distance, and unseasonably cool. Indeed, it is cold!

Based on yesterday's form, Red Bull and Ferrari have the edge - with the Italian team demonstrating that its Silverstone was no fluke - with McLaren playing catch up. Lewis Hamilton has virtually written off any hope of qualifying at the front, far less taking pole, but believes his race pace will be another matter.

On the other hand, the threat of rain tomorrow, not to mention talk of teams needing to make last minute pit stops, anything can happen and most probably will.

With minutes to go, the Lotus crew is working furiously on Kovalainen's car, which appears to have a problem at the back, while Renault confirms that Heidfeld is running the forward facing exhaust, the team encountering overheating problems with its rearward facing layout yesterday.

D'Ambrosio leads the way when the lights go green, the dark clouds causing a significant number of drivers to opt for an early run. Vettel is one of the early birds. Lotus confirms that Kovalainen has a hydraulics issue but that it will be resolved within the "next few minutes".

On his installation lap Schumacher is told that he has a KERS fault while Ricciardo warns of a strong tail wind going into Turn 7. Tyre choices this weekend are medium (prime) and soft (option).

Five minutes into the session all but Kovalainen have been out, with Petrov the only driver to have completed two installation laps.

D'Ambrosio is the first driver to come up for a second run, the Belgian doing better than many expected thus far this season.

As the Virgin driver begins his first flying lap, the car looking a real handful, Chandhok heads down the pitlane in the Lotus. D'Ambrosio puts the first score on the door, the Belgian crossing the line at 1:46.020.

As d'Ambrosio gets down to a 44.172, Kobayashi, Liuzzi, Rosberg, Heidfeld, Schumacher and Barrichello leave their garages.

Chandok posts 42.384 and Liuzzi 43.463 but moments later Kobayashi crosses the line at 41.078 and Perez at 36.851. Heidfeld splits the Saubers with a 37.002.

Replay shows Chandhok spinning in the final corner, the Indian opting to drive back through the pitlane.

Heidfeld goes quickest (35.881) as Schumacher goes second and Mercedes teammate Rosberg third. However, moments later Rosberg goes quickest in all three sectors crossing the line at 34.872.

Having improved with a 35.255, Schumacher has a worrying moment, the Mercedes clearly a real handful.

After twenty-five minutes Massa, Vettel, Alonso, Webber, Hamilton, Button and Kovalainen have yet to post a time.

Schumacher goes quickest with a 34.418, making it a German 1-2-3-4, what with Rosberg second ahead of Sutil and Heidfeld.

Massa, Vettel, Alonso and the McLarens leave the pits, leaving Webber to watch the action.

On his first flying lap Hamilton goes fourth (35.267), while Massa goes sixth (35.387).

As Webber finally leaves the pits, Button goes quickest (33.646) and teammate Hamilton second (33.694). Vettel is fourth (33.921) and Alonso ninth (34.512).

No sooner has Perez raised the benchmark with a 33.531 than Alonso ups the ante with a 33.302. However, Hamilton is on a hot lap, going quickest in S1. On his first lap Webber goes eleventh with a 35.208. Next time around the Australian goes second with a 33.492.

Kovalainen finally leaves the pits, the Finn immediately going nineteenth courtesy of a 37.933.

A 33.243 sees Vettel take the top spot, however, moments later Button posts 33.106 having gone quickest of all in S3.