Button says a lot of work needed on RA108

Both Button and teammate Rubens Barrichello suffered from a general lack of mechanical grip during the test, with neither managing to show the sort of pace the Japanese squad are hoping for in order to bounce back from their dismal 2007 season.

The good news for the team, however, was that the stability problems suffered under braking last year are nearly gone.

Button was happy with the car's reliability, but he admitted there is still a lot of progress to be made.

"I am pleased with the reliability of the car," said Button at the end of the test. "Generally, we have made some progress this week but there is still a lot of work to be done in the forthcoming tests. The car is completely new which means we are starting from zero in terms of developing the set-up.

"We are also experiencing some drivability issues as we work with the new ECU. The weather conditions today meant that I was able to get my first wet running in without traction control, which was good. On to Jerez next as we continue to keep pushing forward with developing the car."

Barrichello added: "There is plenty of potential in terms of working on the speed of the car in the coming tests and this will come as we continue to make progress with the set-up. At this stage I am happy that reliability is certainly on our side."