Williams rebuff BAR offer in battle to secure Button

A year after Jenson Button tried to jump ship and join Williams for 2005, his BAR-Honda team have offered Sir Frank Williams their test driver Anthony Davidson and a financial sweetener of £5m in a desperate attempt to hang on to Britain's leading race driver.

After his planned switch was stymied by the Contracts Recognition Board last September, Button signed a contract to rejoin Williams for 2006 and they intend to hold him to it. In Germany last weekend, where Button finished third, Williams turned down his verbal request to be released, and said: "We have an existing contract for Jenson to join us in 2006. There is nothing that will change that."

The BAR team principal, Nick Fry, said that it would breach Button's human rights to force him to honour a contract he no longer wants to be bound by. But Fry knows only too well that Williams now have the high ground with the CRB that was the key to BAR retaining him for 2005.

Williams are less attractive to Button after their poor performances this year accelerated the divorce from BMW. They are seeking a deal with Toyota, but the Japanese motor manufacturer must wait first to see if the financially beleaguered Jordan team can come up with the money. Williams may thus have to rely on Cosworth engines for a stopgap season. Several of their sponsors have medium-term contracts, but having to pay for engines will strain the budget.

"Jenson is a crucial part of our corporate strategy for 2006 and beyond," a team insider said. "He is a great driver and we have always had the utmost faith in him, ever since we gave him his F1 chance back in 2000."

Button only left in 2001 to go to Renault because Williams had a prior commitment to run Juan Pablo Montoya and an ongoing contract with Ralf Schumacher.

"Jenson brings gravitas to any race team, and is an established leader who can push a team forward," the source continued. "There is absolutely no question of us surrendering him."

It is difficult to see where Davidson would fit into Williams, even though they tried to get him as Mark Webber's partner this season. Webber has another year to run on his contract, while Williams have an option on the swift German Nick Heidfeld and no intention of releasing him to drive for BMW's own team in 2006 without financial recompense. Then there is the American Scott Speed, who is trying to break his contract with Red Bull so he can become a test driver at Williams. The team already have Antonio Pizzonia and Nico Rosberg fulfilling that duty, however, and Davidson only performs a similar job at BAR. Only Webber and Heidfeld have real race experience, and all lack Button's status.

"It is clearly in the interests of all concerned that this is sorted out quickly," said Fry, who is offering Williams £4.5m plus Davidson's £300,000 salary for two years. "We want Jenson to stay with us for the rest of his career."

BAR are hedging their bets, however. There have been talks with Rubens Barrichello for some time, but Felipe Massa's recent strong performances - described by team boss Peter Sauber as "flawless" in Germany - have also put the younger Brazilian in the frame.