Uncertainties abound but Hamilton is favourite

Although there were mutterings that the rained-out sessions of Friday didn't mean much, they are almost certainly the most meaningful wet practices of the year to date - in that the forecast for race day is resolutely very wet.

An extra set of intermediates Pirellis were made available to the teams in an effort at encouraging the cars to run in front of a record 80,000 Friday capacity, but only towards the very end of the second session did it become feasible to use this rubber. For much of the time, the risk of aquaplaning was too high to even run with the wet tyres - something that Bruno Senna proved with a heavy crash at Chapel bend in his Williams.

Friday - and likely Saturday and Sunday too - was all about drivers finding a driveable balance and being comfortable in the extreme conditions. Being reactive is prime Lewis Hamilton territory and it was no surprise to see him fastest of the afternoon session, albeit with a time that was only a couple of tenths quicker than that set by the Lotus of Romain Grosjean - who looked equally comfortable - in the morning. Both times were set on the full wet tyres.

The Saubers were quick in practice © XPB

Kamui Kobayashi did 35 laps over the two Friday sessions, by far the most of anyone, and it was almost certainly partly the familiarity with the conditions that allowed him to set the second fastest time of second practice. But the Sauber does seem genuinely at home around the high-speed bends and out on track appears driveable and well-balanced.

Sergio Perez went as far as to suggest that this was 'a winnable race' for them. He and Kobayashi were trading fastest times as the circuit got slightly less wet and Perez appeared to have a small edge in pace, but pitted earlier, allowing Kobayashi to ultimately set a better time.

The Mercedes was comparably quick in the wet - Michael Schumacher ahead of Nico Rosberg by dint of a very late run on inters - and looks capable of racing McLaren, Lotus and Sauber. But we did not see comparable runs from Red Bull or Ferrari, each of which were on different programmes to those setting the fast times.

Of that group of teams, only Mercedes did not bring significant aero upgrades here, the team preferring to better understand the car and its use of tyres before proceeding further on their development path.

Ferrari tech director Pat Fry was particularly frustrated at the weather. The aero upgraded made two races ago in Canada - a more McLaren-like rear body and exhaust arrangement - seem to have brought the car alive and for here the team added a front wing with a new design of endplate.

Alonso destroyed one of these wings with a light brush with the wall at Stowe when running on very worn inters. But of more significance was the fact that Silverstone should have been the first real test of the efficiency of the earlier upgrade, in that they have so far only ran at Montreal and Valencia, neither of them noted aero tracks.

"Hopefully those improvements have carried through," said Fry, "but we don't know yet."

Alonso destroyed one of his new front wings © LAT

The RB8 had a yet-further squeezed lower rear body, with the exhausts now protruding from the sidepod tops. The feeling within the team was not generally optimistic of a repeat of the stunning Valencia form, on account of its strength being in slow corners. There's a general air of acceptance that both the McLaren and Lotus are likely to be faster through the long, high-speed corners of Silverstone and that this will translate wet or in the unlikely event of dry.

Williams has so far not shown any sign of latent frontrunning pace, but that has also been the case at other events this year, in which the car has suddenly come alive during qualifying.

Uncertainties abound, but it would be surprising indeed if Hamilton was not somehow in the very thick of the action this weekend and is the logical favourite.

It would be an entirely appropriate place also for Jenson Button to pull a big result from the bag to get his season back on course.