McLaren drivers Kimi Raikkonen and Pedro de la Rosa dominated the timesheets at Silverstone today, though the Finn out-paced the Spaniard by over a second.

Pedro's programme concentrated on tyre evaluation and set-up work for the forthcoming British Grand Prix, testing both the prime and option tyre. The Spaniard completed short runs in the morning and ran a back-to-back comparison in the afternoon.

An engine failure mid-morning cost him time, however the mechanics performed an engine change and he was able to get back out on track for the afternoon session.

Kimi concentrated on set-up work for the Canadian Grand Prix and tyre evaluation and set-up work for the British Grand Prix. Like Pedro, Kimi completed short runs in the morning and back- to-back comparisons in the afternoon.

Renault had World Championship leader Fernando Alonso and teammate Giancarlo Fisichella on duty.

Having opted not to run on Wednesday, successfully predicting that the test would be hit by heavy rain showers, the French team began its testing programme in earnest today, with both race drivers completing a long programme at the Northamptonshire circuit in preparation for the July's Grand Prix.

The work focused around tyre testing for the upcoming British Grand Prix, in order to extract maximum value from the day after poor weather was again predicted for Friday.

"After the frustration of not running at all on Wednesday, it was good to get some serious running done today," said Chief Test Engineer Christian Silk. "We focused our work around the forthcoming Grand Prix, and obtained good directions on the tyres we want to use in the race.

"Fernando also began some set-up programmes, which we will develop further tomorrow with both drivers if the weather holds."

BAR's Jenson Button finished fourth quickest, splitting the Renault drivers, while teammate Takuma Sato was eighth.

Both drivers spent their early runs working to get a good balance on the car. The Englishman's programme for the day was to run an aerodynamic evaluation, while Takuma ran through an intensive tyre evaluation looking at options for the forthcoming races.

Honda's Otmar Szafnauer revealed to Pitpass that the Brackley team will round off this week's test programme at Monza on Friday, opting not to run at Silverstone.

Red Bull had David Coulthard and Christian Klien on duty, the Scot finishing an impressive sixth fastest, just 0.004s off Alonso's pace.

The Austrian team concentrated on preparations for the forthcoming Canadian and United States Grands Prix, with Scott Speed scheduled to drive the car on Friday.

The Toyotas finished seventh and eleventh as both drivers focussed on set-ups and tyre evaluation. Ralf Schumacher was joined by Jarno Trulli, who tested at Monza on Wednesday.

Rubens Barrichello was Ferrari's sole representative today, as the Brazilian continued with work begun on Wednesday by Luca Badoer, on finding the best set-up for the F2005.