Ahead of this morning's opening free practice session, the air temperature is 23 degrees C, while the track temperature is 35 degrees. It is bright and sunny.

The tyre options this weekend are hard and soft, while only McLaren and Ferrari are using KERS, which should be more of an advantage here than in Monaco.

After the obligatory installation laps, there is no further activity for the next thirty minutes. Eventually, the cars begin to emerge from their garages and the session gets underway in earnest.

Despite a raft of updates, including a new split diffuser, BMW has clearly not made the step forward it anticipated, certainly at this stage, and it isn't long before Robert Kubica is complaining.

Toyota, on the other hand, appears to have rediscovered the pace that was so lacking in Monaco.

With half-an-hour remaining, it is Hamilton in the McLaren who heads the timesheets, ahead of Barrichello, Vettel and Rosberg, Massa, Trulli, Nakajima, Glock, Button and Raikkonen.

Buemi makes full use of the generous run-off, the Toro Rossos propping up the timesheets with twenty-one minutes remaining.

As Raikkonen seeks to improve on tenth, teammate Massa goes second with a 29.445 having gone quickest in the second sector.

At this point the session is red-flagged. It appears that a whole strip of astro-turf used on the run off at Turn 1, has been ripped up, causing problems for Massa and then Fisichella. It might make the circuit look aesthetically pleasing but it clearly isn't up to the job. With the teams about to start their final assaults this couldn't have come at a worse time.

The marshals get to work and have soon ripped up the offending 'carpet', allowing the session to resume with 15 minutes on the clock.

When Buemi improves to eighteenth, this drops Kovalainen to nineteenth, the Finn having only completed 12 laps thus far.

Piquet gets wildly out of shape at Turn 1, the Renault swinging from side to side, yet somehow the Brazilian keeps it under control.

Hamilton goes quickest in the first sector, however, he fails to improve over the course of the whole lap.

Personal bests in all three sectors see Raikkonen improve to seventh with just over four minutes remaining.

The top 15 are covered by less than a second, with both BMWs still over 1.3s off the pace.

Trulli improves to fourth and Raikkonen fifth as Glock goes wide and spins.

Having gone quickest in the first sector, a tow from Rosberg, not to mention KERS, sees Hamilton go quickest in the final sector also, raising the benchmark with a 29.263.

A late charge sees Nakajima go fourth, only to be demoted when Trulli improves to second. Moments later, 'Man Friday' Rosberg posts 28.952 to go quickest, the German having received a welcome tow from Hamilton on the back straight.

The session ends with Rosberg quickest, ahead of Hamilton, Trulli, Vettel, Massa, Nakajima, Raikkonen, Alonso, Barrichello and Kovalainen.

Button is eleventh, ahead of Sutil, Glock, Piquet, Webber, Kubica, Heidfeld, Fisichella, Bourdais and Buemi.

Trulli Glock and Buemi completed the most laps (26), ahead of Raikkonen and Barrichello (25), Rosberg, Alonso and Bourdais (24).

Quickest through the speed-trap was Piquet (190.7 mph), Alonso (189.5 mph) and Hamilton (188.2 mph).

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