The third day of testing at Jerez officially signalled the end of the 2008 Formula 1 season with Sebastian Vettel claiming the fastest time for Red Bull Racing.

Once again, Red Bull, BMW Sauber and Williams were the only teams present at the Spanish circuit as they concluded their preparations for the 2009 ahead of the Christmas break.

With BMW concentrating on their 08/09 interim car and Williams working on aerodynamics, Red Bull were free to make it a hat-trick of fastest times, although it was Vettel who assumed the quickest lap of 1min 16.617secs on this occasion.

The German managed 107 laps as he and Red Bull worked on understanding the new Bridgestone slick tyres. The RB4 ran reliably throughout the day.

"We've had pretty smooth running at this test and have completed a lot of mileage before the end of the year. I think we've done everything we could here, learning about the tyres and next year's regulations and hopefully we will start next year with a car strong enough to challenge the big boys."

Possible Toro Rosso driver Sebastien Buemi, who is filling in for the injured Mark Webber this week, maintained his fine pace to shadow Vettel with a best of 1min 16.998secs. He joined Vettel in working on tyres.

BMW pair Robert Kubica and test driver Chrsitian Klien spent the day driving the hybrid F108.B car, equipped with some of the new bodywork features and the KERS device. They were around 2.5 seconds off Red Bull's pace.

Kubica was marginally quicker than the Austrian, despite suffering a mechanical problem which prevented him from carrying out as much work on the KERS system as planned. Klien, however, was happy with the progress being made.

"We made good progress today", he said. "We still have a lot of work to do on the KERS system. But the promising test results show we are moving in the right direction."

Nakajima, meanwhile, completed the most laps of the day at 131, but propped up the timesheets as he continued to prepare for his second season with Williams. The Japanese driver worked on aerodynamics and tyres.

Lap times Jerez de la Frontera 17/12/2008:

1. Sebastian Vettel Red Bull-Renault 1min 16.617secs 107 laps
2. Sebastien Buemi Red Bull-Renault 1min 16.988secs 92 laps
3. Robert Kubica BMW Sauber 1min 19.013secs 100 laps
4. Christian Klien BMW Sauber 1min 19.066secs 38 laps
5. Kazuki Nakajima Williams-Toyota 1min 19.341secs 131 laps

Conditions: Cold all day. Average air temperature: 9?C

All times unofficial