Ahead of today's second free practice session, the air temperature is 27 degrees C. while the track temperature is 30 degrees.

Jenson Button led the way this morning, ahead of Mark Webber, Lewis Hamilton and Sebastian Vettel, however, it was difficult to make an outright comparison based on times because in addition to the standard prime (medium) tyres, drivers have been given two sets of experimental (soft) tyres with an eye on next season.

Nonetheless, what was clear, other than Rubens Barrichello's engine failure is that both Ferrari drivers were struggling with the handling of their cars. On board footage revealing Fernando Alonso working like a maniac to keep his car on track.

Three regular drivers, Sebastien Buemi, Bruno Senna and Jerome d'Ambrosio gave up their seats this morning - to Jean-Eric Vergne, Romain Grosjean and Robert Wickens respectively - but they are back on duty this afternoon.

Senna is first out once the lights go green, followed by Glock, Alguersuari, Perez, Buemi and a whole host of others. Indeed, in no time at all, all but the McLarens, Mercedes, Vettel and Sutil are on track.

Senna's 47.727 is rapidly beaten and once the dust settles it is Alguersuari who leads the way, the Spaniard having posted a 43.662. All but Rosberg on track.

No sooner has di Resta posted a 42.550 than Webber goes quickest with a 42.002. As Massa continues to struggle with the Ferrari, Vettel posts a 41.392 to take the top spot only to be leapfrogged by Webber and his 40.723. Schumacher goes third with a 41.624.

Drivers are quick to switch to the soft (option) tyres in this session, as Vettel grabs the top spot with a 40.514. Sutil goes third ahead of Schumacher, Button and Hamilton.

Having improved to third (41.002), Hamilton is told that other cars are using the experiments tyres and that this accounts for their pace in sectors two and three. Elsewhere, the cameras pick up on the wobbly front wing on Massa's Ferrari. Also, a hairy moment as di Resta's car breaks loose.

Alonso goes quickest with a 40.141, the Spaniard subsequently pitting as the first phase of the session appears to come to a close. Meanwhile, replay shows Schumacher one of many to make full use of the generous run offs here. In the Ferrari garage, the front wing on Massa's car is changed.

Having gone quickest in S3, Vettel closes to within 0.056s of Alonso. Meanwhile, Schumacher posts 40.866 to go fourth.

A big spin for Webber who immediately returns to the pits. The Australian is currently third, 0.160s off the pace.

Alonso, with sparks from his front wing endplate as it clips a kerb, posts a PB is S1, subsequently raising the bar with a 39.971. On the HRT pit-wall, a worried looking Liuzzi chats with his engineer. The Italian, who has only completed 6 laps, is currently at the bottom of the timesheet (49.804).

With around fifty minutes to go the circuit lights are on as the sun slowly sets.

Ferrari reveals that Alonso's time as set with the experiments tyre, which demonstrates how difficult it is to compare times today. Meanwhile, Pirelli's Paul Hembery admits that Sunday's race should be mostly run on softs with two stops the likely norm.

A 39.970 sees Button go quickest, but moments later he is eclipsed by his McLaren teammate who posts 39.586. Elsewhere, Schumacher goes quickest in S2 before diving into the pits.

With 36:00 on the clock the session appears to be over for Vettel. The German locks up the rear going into Turn 1 and slides sideways on into the barrier. Unable to get going again he climbs from the car, immediately removing his helmet and running back to the pits.

Replay with on board camera shows the German looking at the wall as his car slides, slowly but surely, into the barrier.

Fresh from his appearance in court in Munich, Bernie Ecclestone strolls through the paddock. Back on track, Buemi almost comes to grief where it all went sour for Vettel.

Massa is told that he's braking too early at Turns 18 and 20. The Brazilian responds by improving to fourth with a 39.980.