Red Bull topped the times for the third day in succession on Thursday at the Jerez de la Frontera circuit in Spain, but this time it was the turn of 'A' team member, Mark Webber to set the pace.

Webber, who completed 85 laps in total, was quickest on a 1 minute 19.176 seconds, which was just under two tenths up on his closest rival - although the best time of the week stays at a 1m 18.843s, set by Sebastian Vettel on day 2.

Webber focused mainly on aero development work and suspension changes today, in preparation for the next two races in Hungary and Valencia. The team reported that he made good progress - and that he also carried out some tyre tests to complete the programme that was stated on Wednesday.

"We've had a pretty good two days here. The car ran pretty reliably and we've clocked up some good mileage," said the Aussie. "Today we were mostly getting ready for Budapest, as well as looking at developments for a little later in the season.

"Yesterday we were focusing more on '09, and it was quite a challenging day. Today was better in terms of what we learned, mechanically and aerodynamically. It's been a hot week for the guys working here and they've done a good job."

Nelson Piquet Jr was 'best of the rest' for Renault and he did 95 laps in total in conditions, which were again incredibly hot, with track temperatures once again creeping up to 46?C in the middle of the afternoon.

He ran on grooved tyres to begin with to get a good baseline and understanding of the car before attention shifted to running with 2009 slick Bridgestone tyres as part of the team's preparations for next year.

"It was very hot once again today, but it has been like that all week so we are getting used to it," said Piquet Jr. "We spent most of the day looking ahead to next year by running with slick tyres, which was very interesting.

"They felt good, gave plenty of grip, and the car was working well. We also did some set-up work, evaluating the changes to try and improve the overall balance. So, overall another good day's work."

"The car was working well today and Nelson quickly got in the swing of things," added Renault's chief test engineer, Christian Silk. "We started the day by doing a little bit of work with 2008 grooved tyres, just to see where we were, but we then spent most of the day running on 2009 tyres in preparation for next year.

"The initial signs looked quite good and we have collected lots of data, which is quite encouraging and there were no problems. All that information will go back to the factory and be used when we are working on next year's car."

Next up was Kimi Raikkonen and the Ferrari man was one tenth slower in his F2008, working on comparisons between various different set-up options in preparation for the forthcoming event. He ended the day by running on a set of Bridgestone's slick tyres and seemed happy with the progress made.

"We have done many tests over these two days to try and understand what happened at Hockenheim and now we have a clearer idea on this matter," he revealed. "Today, the car had improved compared to yesterday and we hope to be ready for the next rounds.

"Our opponents are very strong, but there is still a long way to go in this championship and all the time to recover, given that in Formula 1 things can change a lot in no time at all."

Further down the order Force India's 'third' driver Vitantonio Liuzzi was fourth, closely followed by McLaren's tester Pedro de la Rosa. Liuzzi had no problems with his VJM01 and continued putting more miles on the new seamless shift gearbox, as well as doing some aerodynamic work, brake testing and in the afternoon running on the 2009 spec rubber.

"We once again had a very positive day. We could do over 80 laps with the new gearbox without any reliability issues. We also completed some aero work with the new wheel spinners and in the afternoon went onto the 2009 slick tyres to try the different compounds, weight distribution and the set up," he confirmed. "I enjoyed it a lot as there is much more grip and the car seemed very well balanced with them. Finally we did some brake testing to finish off what's been a very positive two days of testing."

de la Rosa's day however, wasn't so productive and he did only 39 laps after some systems issues in the morning resulted in the car stopping on track. He also had an oil leak in the early afternoon, which necessitated an engine change. Despite the limited track time available though, the team insisted that it was able to conduct 'a very positive test of a number of aerodynamic components'.

Sebastien Bourdais rounded out the top six, having taken over the Toro Rosso-Ferrari STR03 from team-mate, Sebastian Vettel, who was quickest on days 1 and 2. The Frenchman began the day evaluating different brake materials and in the afternoon moved on to assessing a wing planned for use when the season heads to Spa-Francorchamps in Belgium.

"The day went well, with the entire programme completed. Tomorrow, Seb will start the day on this year's specification tyres before moving on to do some laps with the '09 spec slicks," added a statement from the Red Bull 'B' team.

Of the rest Kazuki Nakajima was seventh for Williams and he was mainly looking to next week's Hungarian GP, tweaking the set-up on the FW30.

"Taking over duties from Nico [Rosberg], Kazuki joined us at Jerez today for day three of our four day test in Spain," noted Williams test team manager, Dickie Stanford. "To start the session, we continued with our set-up work for the race at Budapest next weekend and then followed that up with 2009 tyre evaluations this afternoon. Kazuki will continue work with the FW30 tomorrow to wrap up our scheduled programme."

Timo Glock was eighth for Toyota and the German reported no ill-effects on his first day back behind the cock-pit following his big crash at Hockenheim on Sunday. Indeed he did 78 laps, his only minor issue - a mechanical problem with the fuel system late on.

"It was good to get back in the car and that was a positive day's testing for us," he reflected. "We pushed hard in the morning and we were able to get through most of our plan for the day before lunch.

"That was useful because in the afternoon here it gets too hot and the track is just too slow to get a clear picture out of the car. Late on we had a fuel system issue but we had already gathered the data we wanted. The main thing is that I've made a full recovery from my accident on Sunday and I feel fine."

The only other runners on track were Honda's Rubens Barrichello and BMW Sauber's Nick Heidfeld, who came in ninth and tenth respectively, the latter having taken over from Christian Klien.

Heidfeld did 97 laps in total - the most of anyone runner - his best a 1 minute 20.896 seconds, which was around a second off the pace. He was looking at development work with the 2009 slick tyres and collected data on mechanical and aerodynamic set-up options for next year's car.

The four-day Jerez test is now due to conclude on Friday, with Ferrari, McLaren, Toyota, Red Bull Racing, Renault and Force India bringing in Felipe Massa, Heikki Kovalainen, Kamui Kobayashi, David Coulthard, Romain Grosjean and Adrian Sutil respectively. Nick Heidfeld, Kazuki Nakajima and Sebastien Bourdais will all run for a second day in a row.

To see the testing times from day 3 click here.