Ahead of today's opening free practice session, the air temperature is 19 degrees C, while the track temperature is also 19 degrees. The sun is shining, but there is plenty of cloud in the sky.

While both of today's sessions should be rain-free, its is widely predicted that there will be rain during tomorrow's sessions and during the race on Sunday. If correct, this means that much of today's work will be academic.

The lights go green, and first out is Giancarlo Fisichella who is contesting his two-hundredth GP this weekend. Coulthard, Heidfeld, Vettel and Rosberg are the the other early risers.

Lewis Hamilton is another driver to come out early, the McLaren driver locking up and cutting the Swimming Pool corner on his installation lap.

There's a warm welcome from the (sparse) crowd as Michael Schumacher makes his way to the Ferrari garage.

Nine minutes into the session, everyone, bar the Ferrari duo, as been out for the obligatory installation lap.

Vettel is the first driver to come out for a second run, followed, moments later, by his teammate. The Toro Rosso drivers are racing the STR3 for the first time this weekend.

The German posts the first time of the weekend, crossing the line at 1:28.486, moments later, however, Bourdais posts 25.255.

Having completed 17 laps between them, the Toro Rosso duo return to the pits, Bourdais topping the timesheets with a 22.219, his teammate just 0.135s behind. Vettel, who tantalisingly goes quickest in the second sector before returning to the pits, will take a 5-place grid penalty on Sunday.

It's like Noah's Ark, as the Toro Rossos return to the pits, the Williams duo leaves. Upsetting the symmetry, Glock and Piquet also head down the pitlane.

Rosberg goes quickest with a 18.423, a huge 3.796s quicker than Bourdais. Next time around the German raises the benchmark with an 18.040, as teammate Nakajima goes second (22.132).

As Glock and Trulli go second and third, all eyes are on Massa and Raikkonen, who prepare to start their second lap of the day.

Having been 'conservative' on the first lap, Massa improves to third next time around. Meanwhile, Trulli goes second.

As Hamilton goes quickest in the first two sectors, Button and Barrichello go third and fourth. The McLaren driver, who finished second here last year, goes quickest with a 17.593.

Massa goes second (17.597), ahead of his Ferrari teammate, as Hamilton improves to 17.078.

For a brief moment, Raikkonen goes quickest in the second sector, but the Finn is instantly eclipsed by Hamilton. The Englishman improves with a 16.612 as the Finn posts 16.823. Elsewhere, Alonso goers fourth, ahead of Kovalainen.

The session appears to be over for David Coulthard, who pulls to the side of the track just after exiting the tunnel. A disappointing start to the weekend for the Scot who has won here twice before.

Approaching half-time, Kubica goes fifth, the Pole posting 17.743. His teammate and Coulthard are the only driver yet to post a time.

It's: Hamilton, Raikkonen, Massa, Alonso, Kubica, Webber, Kovalainen, Rosberg, Button and Trulli.

Heidfeld is on track, the German going thirteenth with his first effort (19.022).

Almost all of the running has been on the soft option thus far, with no sight of the super-softs.

Fifty-five minutes into the session, the red flags come out but it is unclear why. Shortly afterwards, Kubica is told that it is because there "debris on the track" at Ste Devote. Sure enough, the camera cuts to officials carrying out some work at exit to the first corner.

Ah ha, replay shows that a drain cover has worked loose and water is leaking on to the track. Not exactly what you want on any corner, particularly Ste Devote.

The good guys from Azur Metal get to work on the offending drain cover, the clock showing that there are twenty-five minutes remaining.