Red Bull's Sebastian Vettel topped the timesheets at Jerez de la Frontera today as the third, and penultimate, pre-season test got underway.

As expected, rain once again caused problems with one team describing the ever changing conditions as "horrid", what with gusting winds and intermittent heavy showers.

As well as the weather, teams and drivers who had already seen their programmes compromised here last week had to endure a number of red flag periods as some drivers span off and others stopped out on track. Furthermore, at one stage the official timing system shut down meaning that several drivers lost recorded lap times.

"We got a lot of laps done and the car has been good and reliable," said Ian Morgan, Red Bull's head of race engineering. "We've made a few small changes but we didn't get through as much as the programme as we'd hoped because of the weather. Sebastian and the car were consistent on the long runs in the dry which is promising.

"We're continuing to make steady progress; the car is better than it was last week and every time we turn a wheel we seem to be moving forward a little bit."

Despite the conditions McLaren continued with its development of the MP4-25, making solid progress with the car's balance and set-up, based largely on a thorough evaluation of and response to the data gathered at last week's running at Jerez.

Lewis Hamilton caused an early red flag during the morning's running when his car was stopped by a minor systems error. However, thereafter, he ran without problems and was able to achieve some encouraging times over several long runs. A late run with a fuel load saw the 2008 world champion move up to second on the timesheets just 0.424s off Vettel's pace.

Tomorrow, the Woking team will continue with its reactive programme, continuing to put miles on the car while simultaneously looking at improving performance.

Ferrari described today as a "day of hiccups", the Maranello outfit clearly having a difficult time of it. Already frustrated by the weather, the Maranello team's mood wasn't helped when Felipe Massa stopped out on track just before 13:30. Having brought the car back to the pits - during which time the Italian team went to extraordinary lengths to prevent anyone getting too close, especially to the rear - the team worked on the F10, carrying out various modifications and enabling the technicians to check the data relating to different set ups.

"This wasn't the best day of testing," said Massa, who drove the brand new 282 chassis today. "The track conditions changed all the time and then we might have lost the best moment in the early afternoon. We had to adapt to the situation, trying to make the best of it. We hope that the situation will improve tomorrow. Although the forecast is not really encouraging."

On the agenda for Toro Rosso camp was a brake system evaluation and fortunately, there were enough dry laps available for Sebastien Buemi to complete this. The STR5 encountered no major technical problems and the Swiss driver - who will be in action again tomorrow - completed 79 laps on his way to posting the fourth best time of the day.

Sauber continues to impress, Pedro de la Rosa finishing the day fifth quickest as the Swiss team used the day to try out all the different tyre specifications.