Ahead of today's sole practice session, the air temperature is 22 degrees C while the track temperature is 26 degrees. After yesterday's sunshine it is a little overcast this morning.

While Fernando Alonso topped the timesheets yesterday, both sessions were marred by crashes, Sebastian Vettel becoming the latest victim of the Champions' Wall in the first session and Kamui Kobayashi, Adrian Sutil and Jerome d'Ambrosio all encountering the barriers in the second.

With last year's Grand Prix being the blueprint for the rubber provided by Pirelli this season it's hardly surprising to hear that we could be facing four or even five stops per driver in tomorrow's race. The lack of grip is one of the reasons for the numerous offs and crashes, over enthusiasm being another.

Virgin has revealed that d'Ambrosio will be using the spare chassis while Pedro de la Rosa has admitted that he was given only ten minutes notice that he would be needed to standing for Sergio Perez.

Despite crashing out in the opening session, Vettel was on form in the second splitting the two Ferraris. The McLarens were also up there while di Resta put his Force India sixth overall. Fact is however, that the numerous red flag periods yesterday meant some teams were able to carry out their full programme which means there is still no clear picture of the true standing here - witness the fact that the Mercedes duo was nineteenth and twentieth.

Ten minutes before the session gets underway, Bob Constanduros texts us to say that he doesn't think Mark Webber will be doing much work this morning as his team is working on his KERS. The system has been a real bugbear of the Austrian outfit this season.

The lights go green and Glock leads the queue of drivers eager to get to work, Vettel and Massa among them.

Five minutes into the session all but Webber and Schumacher have been out. As Bob said, the Red Bull crew is working furiously on the Australian's car which is currently in pieces.

Nico Rosberg posts the first time of the day, the German crossing the line at 1:16.977. Next time around the German improves to 15.934.

As Schumacher comes out to play teammate Rosberg gets down to a 15.034. Kobayashi is also on track.

Schumacher's first lap is a disappointing 22.535. As Petrov, Karthikeyan and Kovalainen head down the pitlane the German improves with a 21.137, indicating he might be on a heavy fuel load.

As Kobayashi goes second (18.674), Red Bull confirms that Webber has a KERS battery issue.

Kovalainen goes third (19.231), ahead of Karthikeyan, Schumacher, Liuzzi and Petrov as Button heads down the pitlane.

Petrov improves to second with a 16.894 as teammate Heidfeld posts 18.230 to go fourth. Moments later Button goes third with a 16.997.

On his second flying lap Button improves to 15.208 which puts him second, 0.174s off Rosberg's impressive pace.

A 15.304 sees Vettel go third ahead of Petrov and Heidfeld as Massa and Alonso begin their first flying laps.

Despite completing seven laps on his soft (prime) tyres Button improves to 14.942 to go quickest. Rosberg is back on track, this time on the option (supersoft) rubber. The German immediately goes quickest, crossing the line at 14.180. However, moments later Vettel (prime) posts 14.162.

Behind Vettel and Rosberg, Massa goes third and Alonso fourth. Hamilton's first flying lap sees the McLaren driver post a 16.291. Rosberg raises the benchmark with a 13.919. Still no times from d'Ambrosio, di Resta or Webber.

Hamilton takes to the grass between turns 3 and 4, the spot that caught out several drivers yesterday.

At half-time, it's: Rosberg, Vettel, Alonso, Massa, Button, Hamilton, Heidfeld, Petrov, Buemi and Maldonado. Schumacher is down in twenty-first however, he hasn't run on the option tyre or a lighter fuel load.

Hamilton improves to fourth (14.795), as Kobayashi makes full use of his DRS to pass a slower car on the main straight. The Japanese driver is currently fifteenth, just behind teammate de la Rosa.

As Rosberg is told to watch his rear tyres, Schumacher (on options) improves to seventh with a 15.327.