Ahead of today's sole free practice session the air temperature is 22 degrees C, while the track temperature is 35 degrees. Once again it is bright and sunny.

Lewis Hamilton topped the timesheets in both of yesterday's sessions, and the pace of his teammate, Nico Hulkenberg, not to mention the gap to the opposition, suggests that Mercedes could give Red Bull a real run for its money this weekend.

Not wanting to show any bias, with four races in the next five weeks we really need to see somebody - anybody - take the fight to Sebastian Vettel, if only to give fans in Europe to get out of their beds... total sympathy to our friends in Australia and New Zealand and over there on the west coast of the USA.

Behind the Red Bulls and Mercedes, we had the Ferraris and Lotus', Kimi Raikkonen showing no ill effects following his crash in FP1.

Jenson Button is looking fairly strong in the McLaren, while the Force India duo were covered by just 0.001s.

Behind them it was pretty symmetrical, the Saubers, heading the Tor Rossos, Williams, Caterhams and Marussias.

Tyre options this weekend are medium (prime) and supersoft (option), while, unlike 2012, this year there are two DRS zones. The detection point of the first is 70m after Turn 2, with activation 360m after Turn 2. The second detection point is 60m before Turn 16 with activation 95m after Turn 18.

We witnessed a time difference of about a second between the two compounds on Friday, though we would expect this to come down a bit today.

A number of teams are, most likely Mercedes and Lotus, are probably going to fine tune their cars in order to maximise performance in qualifying, but this will surely compromise them tomorrow.

The lights go green and Chilton is first out, followed by Bianchi, Grosjean, Ricciardo, Vergne, Maldonado, Gutierrez and Raikkonen.

While the threat of a tropical storm now appears to have receded, it is thought temperatures will be significantly cooler tomorrow which will cause further problems.

Within the first five minutes all but the Force Indias have been out, the Silverstone outfit locked in battle with McLaren for fifth in the championship.

Pic posts the first time of the day, the Frenchman crossing the line at 1:43.170. Elsewhere, Hamilton complains of a vibration through the brake pedal when he hits the brakes.

As Van der Garde posts 42.732, teammate Pic improves to 42.730. The Force India duo head down the pitlane.

No sooner has di Resta gone third (50.478), than teammate Sutil posts 42.240 to take the top spot. However, Webber is starting his first flying lap of the session, the first of the big guns to do so. As one might expect he is quickest in all three sectors, easily leapfrogging Sutil with a 39.330.