Ahead of today's second session the air temperature is 18 degrees C, while the track temperature is 21 degrees. Though it stopped raining towards the end of this morning's session it soon started again, causing problems for the GP2 drivers.

With five minutes to go before the session gets underway the rain has stopped however, there are some very ominous clouds all around the circuit.

All of which is very frustrating for the teams most of which are running new components, despite only being able to work for one week since Hungary. Renault, in particular, has a massive upgrade here, though the drivers have seen little benefit thus far.

The lights go green and Buemi heads down the pitlane on full wets, the rooster tail of spray behind the Toro Rosso clear proof of how damp the track remains. Schumacher, Vettel and Webber are also keen to get back to work.

While the majority of drivers return to their garages after an installation lap, Yamamoto has the honour of posting the first time of the afternoon, the Virgin driver crossing the line at 2:09.031.

Ten minutes into the session, Massa goes quickest (2:04.070) however, moments later teammate Alonso posts 2:00.481.

Alonso raises the benchmark with a 1:59.490 as Liuzzi goes second and Petrov third. Moments later Sutil posts 2:00.432 to leapfrog his Force India teammate.

Hamilton is on track on inters, the Englishman tentatively feeling his way around the track. We say tentatively when in actual fact he goes quickest in the second sector and subsequently crosses the line at 1:59.397 to go quickest.

Having seen this his rivals head back to the pits to make the switch to inters… at which point it begins to rain again. The sudden downpour immediately catches Liuzzi and Glock out both spinning off. While the Italian is able to return to the pits - with great caution - it's all over for the Virgin driver.

As Hamilton goes quickest in S1, it's clear that the rain is only really falling in S2.

That said, Massa goes quickest in S2, subsequently crossing the line at 58.591 to go quickest. Moments later Kubica posts 58.311 the rain having moved elsewhere.

A very hairy moment for Schumacher in Eau Rouge, the rain master demonstrating that he's lost none of those special skills. The German posts 59.219 moving up to fourth behind Kubica, Webber and Massa.

With Glock out and di Grassi yet to post a time it's a bad start to the Spa weekend for Virgin.

A 58.149 sees Sutil go quickest, the German repeating the excellent form we saw this morning. Barrichello moves up to fifth with a 58.994.

Di Grassi finally gets his name on the timesheets, the Brazilian posting 2:01.689 to go nineteenth. Elsewhere, there are mechanic swarming over Vettel's car, almost a dozen of them.

With the rain stopped there are now great patches of blue sky, indeed, on some parts of the track there is a clear dry line emerging.

At half-time, Alguersuari is the first driver to take a gamble and switch to (hard) dry tyres. The Spaniard goes quickest in the second and third sectors crossing the line at 58.317 to go third. However, as his rivals take note we are warned that a further rain shower is around ten minutes away.

Next time around Alguersuari posts 55.329 eclipsing Sutil by 2.8s. As Trulli runs wide, Button leaves the pits on a set of option (soft) tyres.

Kobayashi (hard) posts 53.678 and Alguersuari (53.910) as Buemi moves up to third with a 56.465.

As Kobayashi raises the benchmark with a 52.625, Button posts a personal best in S1. The world champion posts another personal best in S2, improving from sixteenth to third with a 53.719.

As Button begins his next lap, Webber slows dramatically on the pit straight while Barrichello has a spin elsewhere. Having been alerted by his crew to ease off, Webber is now told that there is nothing wrong with his engine and that he should stay out.

Button goes quickest with a 51.137, subsequently improving with a 49.755. Massa (hard) posts 50.266 to go second only to be demoted by Kubica (50.250) moments later.