Formula One's governing body yesterday approved the use of a car part that helped Brawn GP's Jenson Button win this season's opening two races.

The FIA's International Court of Appeal ruled that the rear diffusers are legal and "comply with the applicable regulations". It rejected an appeal by four teams against the technology, which channels the flow of air from the front to rear and helps create greater downforce through corners.

The decision was a victory for diffuser users Brawn GP, Toyota and Williams and could force their rivals to quickly add the devices to catch up.

The ruling means the teams with diffusers will keep the points they won in the first two races, with Button leading the drivers' standings after victories in Australia and Malaysia.

Button has 15 points, five more than teammate Rubens Barrichello. Toyota pair Jarno Trulli and Timo Glock are next.

Brawn GP, the former Honda team which was saved by a last-minute buyout by Ross Brawn, is the first new outfit to win its opening two races since Alfa Romeo in the inaugural F1 season in 1950.

Ross Brawn said he was "pleased" with the ruling, which he said "brings this matter to its conclusion".

"We respect the right of our competitors to query any design or concept used on our cars through the channels available to them," he said in a statement.

The verdict was a defeat for rivals Ferrari, Renault, Red Bull Racing and BMW Sauber - and could force them to redesign their cars to help close the gap. The next race is this weekend's Chinese Grand Prix in Shanghai.

Williams chief executive Adam Parr predicted the rival teams would install rear diffusers "within days".

Ferrari and the three others had filed appeals with the FIA, questioning the stewards' decision in Australia and Malaysia to allow Brawn GP, Toyota and Williams to race with rear diffusers. The rival teams argued the diffusers could breach new aerodynamic regulations.

FIA officials held an eight-hour hearing in Paris on Tuesday, and handed down the ruling yesterday.

"Based on the arguments heard and evidence before it, the Court has concluded that the stewards were correct to find that the cars in question comply with the applicable regulations," the brief FIA statement said.

Parr described Tuesday's hearings as lengthy and contentious, and said it was a "relief" that the process had reached an end.

"It's a subject that is inevitably going to arouse strong feelings," he said by telephone.

BMW motorsport director Mario Theissen said the team would accept the decision but didn't consider it fully legitimate.

Theissen said the ruling "doesn't achieve the reduction in downforce and cornering speed intended ... when the new regulations were drawn up."

The decision also means "seven teams will have to invest heavily in carrying out the necessary modifications to their cars," he said.

Toyota welcomed the ruling, saying it had studied the wording of the 2009 regulations to make sure the team interpreted them correctly.

"I was confident the Court of Appeal would reach this verdict and I am satisfied with it," Toyota chairman and team principal Tadashi Yamashina said. "This has been a challenging period for Formula One and I am pleased this issue is now in the past and we can focus on an exciting season on the track."

(AP via China Daily April 16, 2009)