The Pirelli PZero Blue intermediate tyres and PZero Orange wet tyres were the unexpected stars of the show today, after both free practice sessions were held in intermittent rain. The weather in England is renowned for being unpredictable, and Friday was a perfect example, with rain that ranged from light to heavy and cool ambient temperatures of 15 degrees centigrade, with a track temperature of 16 degrees.

The first drivers ventured out onto the track this morning on the full wet tyres. As the surface dried out, they progressively switched to the PZero Blue intermediate tyres. These tyres have impressed so far with their range and versatility, helping McLaren driver Jenson Button to a memorable victory in Canada last month from the back of the field.

Red Bull Racing's Mark Webber - the winner in Britain last year - used the PZero Blue intermediate to set the fastest time of 1:46.603 in FP1 this morning, going more than half a second faster than Mercedes driver Michael Schumacher, who was second.

At the end of the session McLaren's Lewis Hamilton and Ferrari driver Fernando Alonso also tried out the PZero White medium compound slick tyre: part of the allocation of two extra sets of medium-compound tyres given to each team for Friday only at Silverstone. Although the surface was still too damp for a slick tyre, this enabled their teams to carry out some aerodynamic evaluations that will be useful for the rest of the weekend.

Conditions in the afternoon were even wetter, with heavy rain and high winds of 10 metres per second. Many of the leading runners did not come out until the closing minutes of FP2, when Ferrari's Felipe Massa was quickest on the PZero Blue intermediate, thanks to a time of 1:49.967. Mercedes driver Nico Rosberg was second-fastest, also using the intermediates.

Some recent regulation changes have allowed the teams to have an extra set of intermediate tyres available to them over the course of the weekend, bringing each driver's total allocation for rainy conditions up to four wet tyres and four intermediates per grand prix.

However, they may not need them all: the forecast for the rest of the weekend in Britain indicates that conditions will clear up, with dry weather predicted for Saturday and Sunday.

Paul Hembery: "The weather conditions have obviously meant that today was inconclusive, but we've confirmed again the versatility and wide operating range of the PZero Blue Intermediate tyre in particular, while the teams have been able to work on a wet set-up. One of the main objectives of today was to establish an accurate crossover point between the wet and the intermediate tyres, and we gathered a lot of useful information about that. While the rain has been pretty horrible, it's done nothing to dampen the enthusiasm of the British fans, who have turned out in huge numbers at what is an absolutely iconic venue. The situation today makes tomorrow's qualifying session even more unpredictable: the work done during the final free practice session is going to be absolutely critical."

To check out our Silverstone practice gallery, click here.