Ahead of today's second practice session the air temperature is 27 degrees C, while the track temperature is 36 degrees.

Lewis Hamilton led a Mercedes 1-2 in this morning's session, and while that might sound as though the German team had things all its own way that isn't strictly true.

The pair were comfortably quickest and after just seven laps apiece appeared to have called it a day satisfied with their morning's work. But then Fernando Alonso went quicker causing the pair to have to come out again.

Talking of Alonso, there was a strange moment when the Spaniard was sent out on three primes and one option, his crew quickly realising its mistake and running out to rescue him before he took to the track.

There were no major issues in a session which saw three test drivers - Robin Frijns, Giedo Van der Garde and Felipe Nasr - on duty, though, as usual, many drivers found themselves struggling for grip. That said, Kimi Raikkonen gave his crew some work to do when he damaged the floor on his Ferrari after taking a ride over the kerbs which launched the car into the air.

On the other hand, at a time when many are criticising the new regulations, both Caterhams were slower than the quickest time set in practice by the GP2 runners.

Interestingly, this session starts at the same as Sunday's race, the event being held later than ever before, essentially a night race. As a result the floodlights are on. More importantly however, temperatures are down by around ten degrees... And will get cooler.

Sutil is first out, the German planning to race on Sunday without a drink bottle in an effort to keep down to the minimum weight.

As the German begins his flying lap, Ericsson, Grosjean, Kvyat, Gutierrez and Kobayashi join him on track.

Sutil crosses the line at 1:39.438 as more and more drivers pour on to the track.

As Button goes quickest (38.235), Kvyat complains - quite excitedly - that there is something wrong with the down shift on his Toro Rosso.

As Magnussen goes quickest (37.973), replay shows teammate Button getting in a tangle with Maldonado and Ericsson in T1.

Raikkonen goes third (38.396) ahead of Perez and Kvyat as Raikkonen locks-up in T10.

Hamilton goes quickest in the first two sectors as Perez has to avoid a very slow Rosberg in T14. As Hamilton goes quickest (36.506), Perez is told that if he hadn't lost time in the earlier incident he would have gone second.

Alonso goes second (37.079) as Rosberg turns right instead of left at T10 clearly feeling he wasn't going to make the corner. Elsewhere, Grosjean really struggling for grip.

"Too much understeer at the moment," complains Rosberg who subsequently posts 36.601 to go second.

The stewards announce that they are to investigate the Rosberg/Perez incident after the session.

Hulkenberg, who really is on a roll at present, posts 37.441 to go fourth, ahead of Magnussen, Button and Raikkonen.

No sooner has Vettel gone fourth (37.229) than teammate Ricciardo posts 37.037 to slip in behind the Mercedes duo.