Ahead of today's second practice session the air temperature is 30 degrees C, while the track temperature is 39 degrees.

We saw lots of offs this morning the greenness of the track - not to mention the dust - catching almost everyone out. Then there was the red flag period when a dog ran on to the track.

The big news however, is that pace-setter Lewis Hamilton and Sergio Perez have both been handed grid penalties for Sunday's race after being adjudged as having ignored a waved yellow flag right at the end of the session - when the Englishman posted his best time.

It was pretty much business as usual earlier, the Red Bulls and McLaren leading the way, while Alonso, like Maldonado at Williams, was sidelined by an engine failure.

The lights go green but unlike the first session there is no mad rush to be first out, Adrian Sutil having won that particular little game this morning, though Karun Chandhok did complete the first timed lap.

In terms of offs, Turn 5, in particular, is catching drivers out, while the very bumpy grass covered runs offs are causing all manner of problems for those that run across them - and plenty have.

D'Ambrosio finally breaks the deadlock, followed by Petrov, Maldonado, Kovalainen, Karthikeyan, Trulli, Kobayashi and Rosberg.

Tyre options are reversed this weekend with softy being the prime and hard being the option.

As d'Ambrosio posts 38.299 and Petrov 35.418, Kovalainen is the first driver to fall foul of Turn 5, the Lotus kicking up a great cloud of dust.

In no time at all there are 19 drivers on track, the McLaren duo, Schumacher, Barrichello and Alguersuari being the spoilsports.

Sutil goes quickest (30.641), ahead of Buemi, di Resta, Maldonado, Petrov, Senna, Kobayashi, Kovalainen, Alonso and Perez.

With the spoilsports now on track, nine minutes into the session all 24 drivers are on track.

Buemi goes quickest (29.272) however, all eyes are on Vettel who goes quickest in the first two sectors and again in the third crossing the line at 28.014. Moments later, teammate Webber goes third with a 29.639.

Hamilton leapfrogs Webber with a 29.148, the Englishman knowing that he has a mountain to climb in terms of that grid penalty.

Button goes second with a 28.232 as Maldonado's session appears to be over before it begun, the Williams drivers stranded in the gravel after spinning off. Marshals run to his assistance but all they do is further embed the car in the kitty litter.

Hamilton goes quickest (27.261) having posted purples in the final two sectors. The Englishman is on the soft tyre, a number of drivers complaining that the hards offer no grip.

A 26.492 sees Vettel re-take the top spot as Maldonado's Williams arrives back in the pits. Senna goes off after tripping up over his Renault teammate, the Brazilian subsequently returns to the pits.

Having posted a PB in S1, Button runs a little wide as he passes Rosberg. Nonetheless, he posts a PB in S2 only to lose time in the final sector and thereby fail to improve.

As Massa improves to fourth with a 26.923, the Brazilian having gone quickest overall in S2, Button also improves, the Englishman going third with a 26.714.

Vettel consolidates his position with a 26.320 while fellow German Schumacher remains rooted to the bottom of the timesheet over 11s off the pace. The Mercedes driver has only completed 6 laps, according to his team the seven-time champion is merely collecting data.

Currently fifth, Alonso complains of a bad vibration. Elsewhere, teammate Massa posts 26.589 to go second, again the Ferrari driver is quickest of all in the twisty second section.

At half-time it's: Vettel, Massa, Hamilton, Button, Alonso, Webber, Buemi, Senna, Kobayashi and Petrov.

D'Ambrosio's session is over, the Belgian loses it coming out of Turn 11 and clouts the barriers opposite at Turn 12. The rear end of the car is badly damaged and as the youngster climbs from the Virgin the session is red flagged.