Ahead of today's first free practice session for the Belgian Grand Prix, the air temperature is 22 degrees C, and the track temperature is 25 degrees. It's overcast, and it has been raining earlier this morning, consequently there are damp patches around the circuit. Further rainfall is predicted throughout the weekend, indeed there are dark clouds in the distance, and they appear to be heading towards the circuit.

First out is Nicolas Kiesa, who is followed by Zonta, Wurz and Doornbos. Clearly sensing that weather conditions will be changeable throughout the weekend, Button, Villeneuve, Trulli and Ralf Schumacher also go out for an early installation lap.

Eight minutes into the session, Fernando Alonso performs a practice start at the end of the pitlane, like several other drivers, he has opted for intermediates. Coulthard and Raikkonen are also on track.

Zonta is the first driver to post a time, the Brazilian crossing the line at 2:01.833. Despite losing the back end a little at Bus Stop, Wurz posts a 2:00.253 to go quickest.

It is particularly damp just off the racing line at Eau Rouge.

Zonta is still on track, but is finding it difficult to improve on his best time and remains 1.3s off Wurz' pace.

As Klien comes out fir his installation lap, Kiesa posts 2:2:03.423 to go third quickest. Tonio Liuzzi, in the Red Bull goes second with a 2:01.432.

It's also pretty damp at Blanchimont, the Red Bull throwing up quite a bit of spray.

With twenty-three minutes of the session complete, only four drivers have posted times, and Ricardo Zonta is the only man on track. At the second split the Brazilian is over a second up on Wurz, however, loses pace in the final sector and finally crosses the line at 2:00.658, to go second. Next time around the Toyota test driver improves to 1:56.232, the conditions are clearly improving.

Only two drivers on track - Zonta and Liuzzi - as the Brazilian improves again, this time posting 1:54.104.

There is no sign of any action in many of the garages, with many of the 'big guns' seemingly deciding to miss out on this session.

Liuzzi's Red Bull is very twitchy through Bus Stop, where it is still quite damp. As the Italian improves with a 1:54.375, Enrico Toccacelo leaves the Minardi pit. Kimi Raikkonen waits in his car, impassive.

Liuzzi crosses the line at 1:52.494, as Jean Todt watches his monitor, though there is no sign of either Michael or Rubens.

Ricardo Zonta retakes the top spot with a 1:50.580, as Toccacelo goes fifth with a 2:03.431.

Alex Wurz is back on track, as Toccacelo loses it and flies across the 'kitty litter' at Les Combes. As Wurz improves (53.073), the Minardi is lifted by crane.

Villeneuve, Ralf and Trulli are back on track, as Wurz goes quickest with a 1:50.046. In the McLaren garage, Kimi's car is fired up and it looks as though he's going to come out… then the engine is switched off again.

Felipe Massa goes fourth with a 1:52.978, as Webber and Pizzonia leave the WilliamsF1 garage.

Ralf goes seventh (57.761), as his brother heads up the pitlane.

A 1:49.617 sees Wurz consolidate the top spot, ahead of Zonta, Liuzzi and Ralf.

Button takes fourth spot with a 1:51.682, only to be demoted by Webber, who crosses the line at 1:49.692 to go second. Fisichella posts 1:49.791 to go fourth.

Michael Schumacher goes ninth (51.858) at a circuit which has played a significant role in his career.

Wurz goes even quicker (48.216) as Fisichella goes second, ahead of Zonta, Webber and Liuzzi.

With three minutes remaining, Raikkonen is on track, as Pizzonia goes off.

Michael improves to fifth only to be demoted by Raikkonen, who goes second with a 1:48.537.

Sato goes ninth (51.003) ahead of Barrichello, as Raikkonen takes top spot by 0.010s, giving McLaren a 1-2.

The session ends with Raikkonen quickest, ahead of Wurz, Fisichella, Zonta, Webber, Button, Trulli, Michael, Ralf and Liuzzi.