Sam Michael, WilliamsF1 Chief Operations Engineer, said: "Today in Valencia Marc did long runs to compare the most interesting tyres from yesterday's shorter runs. Software work was also conducted on traction and launch control. We finished off the afternoon with some mechanical set-up changes"

For the other teams present it would be Arrows driver Heinz Harald Frentzen who would set the fast time, with a lap of 1m:12.498. Next came Jordan's Giancarlo Fisichella and Renault's Fernando Alonso.

Frentzen would complete forty one laps in the morning, then he would let F3000 driver Sebastien Bourdais out onto the track in the afternoon. The Frenchman spent his time simply getting use to the A23. He will continue testing on Friday. Bourdais would not surprisingly end the day slowest.

Alonso's test program was aimed at completing the development programme begun yesterday focusing on next season's car. The afternoon was reserved for tyre testing with Michelin. Technical Director Mike Gascoyne commented: 'Overall, a very successful day for us. The performance testing this morning allowed us to complete our work from yesterday, whilst the afternoon was a normal tyre test.'

Sauber's Felipe Massa was fourth. Massa had taken over from Nick Heidfeld. Massa commented on the days testing: 'It feels as if we have tried every conceivable configuration on the car. Certainly the work we have done at this test has enabled to improve it for the French Grand Prix."

For the BMW WilliamsF1 Team there will be a final days testing on Friday, this been the last chance before the Formula 1 summer-break, to further develop the WilliamsF1 BMW FW24 cars.

Pos Driver Team/Engine Times Laps

1. H Frentzen Arrows Cosworth A23 B 1:12.498 041
2. G Fisichella Jordan Honda EJ12 B 1:12.795 092
3. F Alonso Renault Renault R202 M 1:13.269 075
4. F Massa Sauber Petronas C21 B 1:13.715 104
5. M Gene Williams BMW FW24 M 1:14.065 106
6. S Bourdais Arrows Cosworth A23 B 1:15.719 025