Ahead of today's opening free practice session, the air temperature is 20 degrees C, while the track temperature is 27 degrees. With temperatures to exceed 30 degrees at some points this weekend, the government is already warning its citizens to be careful and try to stay cool.

Well, as the 2010 season reaches the half-way mark, one might be forgiven for thinking that it is not the drivers but certain driver who need to stay cool this weekend and for much of the summer thereafter.

With the situation at Red Bull already thought to be 'tetchy', there have been claims this week from both Damon Hill and Mark Webber that it is the situation at McLaren that we should be watching. However, other than no visible signs of trouble brewing between Button and Hamilton, the mighty McLaren PR machine assures us that all is hunky dory. Nonetheless, that didn't prevent yesterday's FIA press conference from descending into farce as Fleet Street's finest insisted on trying to create a story where the teams and driver clearly insist there isn't one.

Elsewhere, Robert Kubica has signed a new two year deal with Renault, Fernando Alonso claims to have put Valencia behind him - even to the point of texting Lewis Hamilton - and the Mercedes duo grow ever more despondent as their team loses ground and credibility.

Other than a major upgrade to the circuit, this weekend sees a number of teams running upgrades also, with McLaren leading the way. With the Woking team due to run its blown diffuser in today's sessions, the team has said that it will allow its drivers to decide whether to persevere with it for the remainder of the weekend.

After the tight confines and sterility of Valencia it is a pleasure to see F1 back at a real circuit, which although somewhat emasculated over the years and lacking in terms of infrastructure - certainly as far as the public is concerned - allows the cars to stretch their legs in front of a passionate crowd.

The big story is that Bruno Senna has been dropped by Hispania for this weekend, his place to be taken by (test driver) Sakon Yamamoto. That said, while Colin Kolles has confirmed the story the team has yet to issue an official statement even as the opening session gets underway.

Talking of test drivers, Fairuz Fauzy replaces Jarno Trulli in this session while Paul di Resta is in Tonio Liuzzi's Force India.

Tyre options this weekend are hard (prime) and soft (option).

De Resta is first out, followed by Chandhok, Kovalainen, Alguersuari, Buemi, Hulkenberg and Yamamoto. To the delight of the partisan crowd, Button is among the first out.

As Button returns to the pits, teammate Hamilton and Fernando Alonso head down the pitlane.

Ten minutes into the session there is nobody on track with all but Fauzy and Glock having completed at least one installation lap.

Fourteen minutes into the session, di Grassi break the deadlock, the Virgin giving the thousands of fans something to actually look at.

As di Grassi head back to the pits, Jenson Button heads down the pitlane performing a practice start when he reaches the green light.

At the end of his installation lap Button puts his foot down as he looks set to post the first time of the day. The world champion crosses the line at 1:37.994, the first timed lap by an F1 car on this revised track. While he fails to improve on his next lap, on his third timed lap he posts 35.580.

Webber goes second with a 35.958 and Yamamoto third (46.640), as Bernie Ecclestone patrols the pitlane like a headmaster.

Webber improves with a 34.681, the Red Bull looking as though its on rails through Maggots and Becketts.

On his first flying lap, Michael Schumacher spins at Village, part of the new complex, however, the German is able to continue. Moments later, Hamilton has a little wobble in the same corner.

A 35.586 sees Hamilton go third, ahead of di Resta, Alguersuari, Buemi and Hulkenberg. Next time around, Schumacher improves to fourth with a 35.663.

Hulkenberg posts 35.118 to go second and di Resta (35.339) third, the Scot watched by his manager Anthony Hamilton. Meanwhile, Mr Hamilton's son runs wide at Abbey.