Ahead of today's qualifying session the air temperature is 28 degrees C, while the track temperature is 50 degrees. After three very warm practice session, and mindful of tomorrow when rain is expected at some stage during the race, it's worth noting that there are a few clouds closing in right now.

Lewis Hamilton has been the pace-setter in all three practice sessions, though this morning teammate Nico Rosberg closed to within 0.047s.

Red Bull's progress has continued with Sebastian Vettel and Daniel Ricciardo finishing third and fourth ahead of Bottas the Ferrari duo.

While Red Bull, Ferrari and McLaren are showing signs of improvement, the jury is out on Williams, the Grover outfit, thus far, not showing the competitiveness we witnessed at Silverstone and Germany.

On the other hand, whilst Lotus is looking stronger, reliability issues aside, Force India had slipped behind Sauber this morning.

Of course, while this was only a practice session the fact is that the impact of the removal of FRIC systems is only now making itself really felt, with some teams clearly losing out. Indeed, the almost symmetrical line up of the timesheet this morning tells its own story... Mercedes, Red Bull, Ferrari, Williams, Toro Rosso, McLaren, Lotus, Sauber and Force India.

Brake issues account for some of the many offs and lock-ups we have seen, though the 'greenness' of the track, the absence of FRIC and high winds have also played their part.

Speaking of brakes, Mercedes has now reverted to Carbone Industrie pads and discs all round on both its cars.

A four time winner here, Hamilton will be looking to make it five and hopefully head into the summer break leading the championship for the first time since Spain. Incidentally, Spain was the last time he started from pole.

In terms of the tyres (medium and soft), we're seeing about 1.6 seconds between the two compounds, and this is not likely to change much, especially as the soft tyre in particular is showing low levels of thermal degradation. Pirelli is currently predicting a two-stop strategy on Sunday.

The two DRS zones, which share a detection point 5m before Turn 14, are 130m after the apex of Turn 14 and 6m after the apex of Turn 1.

The lights go green and Kobayashi, Ericsson and Bianchi, who has been off the pace for much of the weekend, are first out. The Caterhams are already on the softer rubber.

The session is over before it has begun for Maldonado who pulls to the side of the track shortly after locking up at T13. He is within touching distance of the pitlane entrance but his Lotus isn't going anywhere.

Magnussen posts a 28.172, thereby eclipsing Kobayashi's 28.755, but moments later Button posts 26.913.

As Rosberg runs wide at the chicane, Hamilton heads into the pitlane flames pouring from the back of the Mercedes. He jumps out of the flaming Mercedes - no pun intended - his session over. A disaster for the Briton and his team.

"I've got fire," Hamilton tells his team remarkably calmly. Told to stop he says he cannot stop the car, indicating a brake issue. "Stop the car, jump out, jump out," he is warned, "there is a marshal behind you."

All of which puts a bit of a damper on the session.

Bottas is quickest at present (25.690) ahead of Gutierrez, Ricciardo, Vettel, Sutil and Magnussen.

Going quickest in the first two sectors, Rosberg posts a PB in S3, finally crossing the line at 25.353.

As he walks dejectedly down the pitlane, in the background Hamilton's car is still burning.

Ricciardo goes second, ahead of Vettel and Bottas, as the Sauber duo, on softs, go fifth and sixth.

The early elimination of Maldonado and Hamilton could mean a lucky break for a Marussia or Caterham driver. Kobayashi is currently 16th.

Having improved to 25.227, Rosberg looks set to improve again before diving into the pits.

Grosjean, currently 19th, posts a PB in S1 as he looks set to improve, thereby dropping Kobayashi back into the drop zone. He posts another PB in S2, finally crossing the line at 26.136 to go 8th.