Ahead of today's second practice session the air temperature is 29 degrees C, while the track temperature is 45 degrees. It remains sunny and very, very warm, ideal conditions for F1… and particularly the likes of Mercedes.

Lewis Hamilton and Jenson Button topped the timesheets earlier, reaffirming the apparent return to form we witnessed in Germany. However, world championship leader Fernando Alonso, who finished third fastest, appeared to have things under control.

On the other hand, both Red Bulls were over 1.7s off the pace. A normal Friday test programme or a sign that the FIA's closing of the engine mapping loophole is starting to hurt?

Having made way for their teams reserve drivers this morning, this afternoon Bruno Senna, Nico Hulkenberg and Narain Karthikeyan are in action.

Tyres this weekend are medium and soft, though the option tyres didn't make an appearance this morning.

When the lights go green the Marussia duo lead the way. Shortly after, the Caterhams head down the pitlane followed by Raikkonen, Senna and Maldonado.

Pic posts the first time of the afternoon, the Frenchman crossing the line at 32.688. however, this is soon beaten by Raikkonen, Kobayashi, Kovalainen and Senna (27.505).

Less than four minutes into the session there are already eighteen drivers on track.

Rosberg goes quickest with a 26.689 as a succession of drivers run wide at Turn 14.

Having gone quickest (24.110), Grosjean runs wide on to the grass and clouts the barrier ripping off his nose at Turn 7.

In the Ferrari garage the Do-It-All boys are using lots of flo-vis paint on Alonso's car, making use of a sheet to keep paint of the main body of the car.

As the Lotus crew get to work on Grosjean's car, teammate Raikkonen goes quickest with a 22.950. The Finn is now running with the passive F-duct system that he ran this morning and in Germany.

As Button goes second (23.558), all but teammate Hamilton have posted a time. However, the Englishman is on track and moments later posts 23.924 to go fourth.

Momentarily deposed by Alonso (23.300), Button posts 22.963 to re-take second.

Hamilton goes third with a 22.990 but is instantly leapfrogged by Alonso (22.899). Vettel is quickest in S1 but loses pace in the next two sectors.

As Massa goes quickest (22.831) to make it a Ferrari 1-2, Kovalainen is told that there is a rain shower heading towards the circuit and that now might be the time to try the options. Moments later the stewards confirm that rain is about 10km away and moving in.

Speedy work by the Lotus crew sees Grosjean back on track, the Frenchman barely having lost any tracktime following his earlier mishap. Along with Kovalainen, the Frenchman is first to switch to the softer rubber.

Senna, currently eighth, and on mediums, improves to sixth with a 23.219, the Brazilian showing no sign of having missed out by being replaced by Bottas in FP1.

A big wobble for Ricciardo as the Toro Rosso duo continue to struggle, both over 1.8s off the pace at this stage.

Having posted PBs in the first two sectors, Webber eases off in the final turn having lost time in traffic. Elsewhere, Button is on track on the softer rubber.

Complaining of "massive understeer", Grosjean is told to pit immediately. Elsewhere, as Schumacher is told that light rain is expected in ten minutes, Kovalainen runs over some debris.

On his second lap on softs, Button goes quickest in S1. He loses pace in S2 finally crossing the line at 22.747 to go quickest by 0.084s.

Aware of the impending shower, more and more drivers switch to the softer rubber. The exceptions being Hamilton, Vettel, Schumacher and Webber.

Raikkonen goes quickest in S2, the Finn crossing the line at 22.770 to go second. However, all eyes are on Alonso who, having gone quickest in S2, crosses the line at 22.582 to take the top spot by 0.165s.