Ahead of this morning's opening session, the air temperature is 25 degrees C, while the track temperature is 28 degrees. It is bright and sunny.

The tyre options this weekend are medium and soft, while McLaren, Ferrari and Renault are all using KERS.

As far as the circuit is concerned, the only change is that the kerbs at 1, 2, 4 and 5 have been raised. This means that rather than ride the kerbs here, as they usually do, they will now have to drive around them.

The big change since the Belgian Grand Prix is that Giancarlo Fisichella replaces Luca Badoer at Ferrari while Fisi's seat at Force India is taken by Tonio Liuzzi.

The lights go green and it is Buemi who leads the way, followed by Heidfeld, Glock, Vettel and Kubica. Within moments there are fifteen drivers on track.

While most drivers return to the pits having completed an installation lap, the Williams duo stay out. Fisichella heads down the pitlane watched by his manager Enrico Zanarini, a nice little pay-day for the man who previously managed Eddie Irvine.

Raikkonen follows the Brawns down the pitlane leaving Grosjean as the only driver yet to make an appearance. The Frenchman finally makes an appearance fourteen minutes into the session.

With the installation laps out of the way, there now follows the traditional period where drivers and crew chat among themselves and with their crew and basically hang around killing time.

Buemi bucks the trend, the Swiss driver heads down the pitlane bang on the eighteen minute mark. He is joined by teammate Alguersuari. Buemi posts 1:29.387 while his Spanish teammate crosses the line at 31.866.

As Hamilton and Webber head down the pitlane, Buemi crosses the line at 26.214 while Alguersuari gets down to 27.409.

Hamilton is really aggressive, particularly at the second chicane, where he rides the kerbs like a man possessed. Meanwhile, the replay shows the fuel flap fly off the McLaren as he exits the Parabolica.

Hamilton goes second (26.767) and Webber fourth (28.046) ass Kovalainen leaves the pits.

Next time around, having probably learned his lesson, and no doubt having his fillings well and truly rattled, Hamilton is much smoother through the second chicane and consequently improves with a 25.410. Webber posts 26.187.

The crowd cheers and air horns are blown as Fisichella heads down the pitlane to get his Ferrari career well and truly underway. On his first lap the Italian veteran posts a tentative 29.815.

Kovalainen posts 25.507 to make it a McLaren 1-2 as Fisichella makes a mistake at the first chicane. Shortly afterwards, Kubica cuts the first chicane complex entirely.

As Fisichella improves with a 27.357, his Force India replacement (Liuzzi) crosses the line at 31.268. Heidfeld goes third with a 25.453.

Raikkonen posts 25.508 to go fourth, ahead of Buemi, Webber and Fisichella, as the Brawns get to work. Webber complains of understeer at a number of corners as Fisichella cuts the first chicane.

Rosberg goes sixth and Button seventh, as Kubica lists a whole raft of problems he is experiencing with the F1.09.

A 25.126 sees Button split the McLarens as Barrichello goes ninth.

As Hamilton goes quickest in the first sector, Sutil goes second overall, the Force India driver crossing the line at 25.059. However, moments later, Button re-takes second with a 24.706.

In the paddock, Bernie Ecclestone visits the Renault motorhome. Now what could he and Flavio Briatore possibly have to talk about?

At half-time, it's: Hamilton, Button, Sutil, Kovalainen, Raikkonen, Alonso, Rosberg, Nakajima, Buemi and Heidfeld. All but Vettel have posted a time, the German opting to keep his engine use to a minimum.

A 25.026 sees Barrichello go third, making it a Brawn 2-3. The Top 6 are covered by 0.992.

As Grosjean cuts the first chicane, there is a small fire in the back of Button's car which is in its garage. However, by the reaction of the team it is nothing serious.