Jenson Button records the fastest lap time in Jerez

Button won his maiden F1 world title in 2009 with Brawn

World champion Jenson Button has clocked the fastest time of pre-season tests at Jerez over the last two weeks.

The McLaren driver, 30, recorded a time of one minute 18.871 seconds on the final day of the third winter F1 test.

Ferrari's Fernando Alonso was sixth fastest, while Red Bull's Mark Webber was unable to repeat his fast time from Friday as his car stopped on the track.

A final test will run in Barcelona next week before the season-opening race in Bahrain on 14 March.

Alonso clocked the fastest time of the opening winter test in Valencia for Ferrari, while the 2008 champion Lewis Hamiton recorded a time of 1:19.583 at last week's four-day test in Jerez.

With the new season less than a month away the general feeling in the paddock is that Ferrari, Red Bull and McLaren are ahead of the rest of the grid.

606: DEBATE Have your say on the pre-season tests

"The F10 is growing very well and there's nothing that should worry us," said Alonso. We worked on the long run and the signs we got are really positive."

Button's former team Brawn, now Mercedes, look slightly behind the top three even with Formula 1 great Michael Schumacher racing for them, but team principal Ross Brawn believes the German outfit are in "good shape for the start of the season".

"We have been able to make good progress on the set-up of the car and completed a number of our systems evaluations," said Brawn.

Red Bull's Webber added: "We learned a hell of a lot, no question about it. We did a lot of stuff with Renault and also leaned about the aerodynamics and the chassis."

New teams Virgin and Lotus have been the slowest this week but are confident about their progress, while fellow newcomers Campos and USF1 have yet to test or complete their driver line-ups.

Campos restructured their ownership and recruited the experienced Colin Kolles as team principal on Friday.

USF1's chances of making Bahrain look remote amid reports that they have asked to miss the first four races of the season.

Serbian team Stefan GP say they are ready to step in despite not having a 2010 entry.