Ahead of today's sole free practice session, the air temperature is 26 degrees C, while the track temperature is 28 degrees. There is lots of cloud, but the sun is clearly waiting to break through..

Moments before the lights go green, Race Control warns that there is oil at Turn 12.

Despite the threat, a flurry of cars take to the track - Fisichella, Sutil, Piquet, Alonso, Rosberg, Bourdais, Kubica, Trulli, Vettel… in moments even Kovalainen is heading down the pitlane.

The obligatory installation lap completed, the drivers head back to their garages.

Eight minutes into the session, Sutil is the first driver to go out for a second run. The German subsequently posts the first time of the day, 1:42.843. Fisichella, Piquet and Massa are also on track.

While we reported yesterday that there was little obvious difference between the tow tyre compounds hard (soft) and soft (super-soft) the drivers claim that there is a big difference but because conditions were constantly changing it was difficult to compare them.

As Massa goes quickest (41.109) he is watched by former teammate Michael Schumacher from the pit-wall.

Fisichella posts 42.548 to go second, as Raikkonen heads down the pitlane. On his first flying lap the Finn goes fourth (43.134). The World Champion is bumped down the timesheet when Rosberg goes second ahead of Sutil and Fisichella.

Fernando Alonso must have been waving to the crowd during his first flying lap, the Spaniard posts 2:02.695. Meanwhile, Rosberg goes quickest with a 41.012 and Raikkonen takes second (41.030).

As Piquet posts a 1:15 and Alonso posts another two-minute lap, we are reminded of Renault's curious strategy in Hungary, when the drivers intentionally completed a whole series of laps well off the pace.

As Hamilton heads down the pitlane, Heidfeld goes fourth with a 41.261, ahead of Sutil, Glock and Fisichella. Hamilton returns to the pits without having posted a time.

Raikkonen runs wide after the bridge, as Kubica goes quickest (40.367), ahead of Vettel and Nakajima. As you can tell, it is very busy, with only twenty-tow minutes of the session gone.

As Kubica also gets it all wrong at the corner after the bridge, Vettel goes quickest with a 40.109. Bourdais goes third (40.460) to make it a Toro Rosso 1-3.

As Coulthard goes fifth with a 40.789, only Trulli and the McLarens have yet to post a time. That said, the Finn is on track.

Barrichello goes off, and for a short while it appears as though he intends heading off into downtown Valencia to do some shopping. On the pit-wall, Schumacher is less than impressed.

Bourdais complains of "oversteer, locking-up and lack of traction", before we can add, 'and apart from that it's fine', the Frenchman adds: "It's pretty miserable to be honest".

Kovalainen's first flying lap sees the Finn go sixteenth with a 54.046, 13.9s off Vettel's pace. However, next time around he improves with a 40.648.

At half-time, it's: Vettel, Kubica, Bourdais, Coulthard, Glock, Nakajima, Kovalainen, Raikkonen, Sutil and Rosberg.

There are lots of really nice corners here, but as we said yesterday, the track surround is so bland.

Timo Glock is the latest driver to get it wrong at the right-hander after the bridge. No such problems for Rosberg who improves to third. In the BMW garage, Heidfeld is watched by Peter Sauber and test driver Christian Klien.

With twenty-five minutes remaining, Hamilton is finally on track, though still no sign of Trulli, who has only completed an installation lap.

On his first flying lap the Englishman goes quickest in the first sector, however he gets crossed up at the ubiquitous bridge right-hander. At the line it's 45.133, which sees the McLaren driver go eighteenth. Elsewhere, despite his many of problems, Bourdais goes quickest with a 39.593, only to be leapfrogged by his teammate moments later.

A 40.060 sees Hamilton go third, ahead of Rosberg and Kubica. Meanwhile, Vettel looks set to raise the benchmark ever higher. However, despite going quickest in the second sector a poor final sector sees him fail to improve.

Hamilton goes quickest in the first sector and looks set to make a major improvement until he enters the final corner too quickly and blows the lap.