Renault test driver Heikki Kovalainen dominated proceedings on the third day of testing at Jerez.

The Finn's best lap was 0.308s quicker than his nearest rival, Jenson Button, and indeed the fastest lap of the year at the Spanish circuit, out-pacing the previous best, set by Fernando Alonso in February, by 0.102s.

Kovalainen was joined by Argentine RDD driver, Jose Maria Lopez, who was at the other end of the timesheets having posted a best time 2.3s off the pace.

Jenson Button took over from Anthony Davidson for the final day of Honda's the test. The Englishman focused on tyre programmes, evaluating various rear tyre options, before moving onto a chassis set-up programme.

An early afternoon engine failure cost Jenson some running time in the afternoon session, although he was able to complete 94 laps and set the second fastest time of the day.

Rubens Barrichello concentrated on further evaluation work on the aerodynamic upgrade package, followed by a tyre compound programme for the French Grand Prix, also completing 94 laps.

It was a day of mixed fortunes for BMW, for although Robert Kubica and Jacques Villeneuve finished third and fourth, the Canadian was the cause of a number of red flags, once following a mechanical failure, and the others due to 'offs'.

The Pole started the day working on a tyre programme for the French Grand Prix, testing different casings and compounds.

Villeneuve first concentrated on the set-up of the car and then also did a tyre test programme in the afternoon, while Kubica evaluated new aerodynamic parts.

Overall, the team claimed it was a "productive day that revealed some interesting results".

Tomorrow (Friday), Robert and Jacques will continue tyre testing and evaluating new aerodynamic parts.

Pedro de la Rosa, who was quickest on the first two days of testing, could only manage fifth fastest today, as the Woking team continued its Magny Cours preparations. Teammate Gary Paffett was ninth quickest, 0.286s off the Spaniard's pace, as the team concluded its Jerez test.

"Pedro, Gary and the test team have had an intensive and constructive three day session this week, putting in over 2,200km," said Martin Whitmarsh. "With the upcoming break in testing in August, we have some key proving of components to complete as we work hard towards consolidating the performance of the MP4-21.

"Both Pedro and Gary worked through Michelin tyre evaluation for the French and German Grands Prix throughout the week, and the high temperatures at Jerez enabled us to conduct the Michelin programme in similar conditions to those we expect at these two races. Alongside this we have been running with developments to the cooling package, which will be rolled out at Magny Cours."

Ralf Schumacher and Jarno Trulli were on duty for Toyota on a day when air temperatures reached 34 degrees C, and track temperatures hit 51.

"Being that the next race is at Magny-Cours, the track there is a rather well-balanced circuit in terms of set-up," said test team manager, Gerd Pfeiffer. "So today we tried various brake configurations and suspension set-ups in addition to testing different Bridgestone compounds for this track, especially because of its smooth black tarmac. Due to it being rather hot here in Jerez, we could also take advantage of the higher temperatures by testing some cooling packages."

"I am quite happy with today's testing," said Trulli. "We had a trouble-free day with the car and put in quite a few laps. My programme was mainly focused on tyres as well as doing some race simulation and set-up work for Magny-Cours. It was difficult to do some long runs with the red flags we had today, but this is normal and we will make up for this tomorrow."

"In the morning we lost some time due to various red lights," added Ralf, "and then in the afternoon, when the front suspension needed to be checked and the brakes were changed on my car. Nevertheless, we were still able to do some runs on different Bridgestone tyres in preparation for Magny-Cours. The car is feeling otherwise good and tomorrow I hope to put in more runs than we did today."

Today, it was Ferrari's turn to join in proceedings, and with Felipe Massa taking a holiday back in Brazil, Michael Schumacher was partnered by Luca Badoer.