Sir Frank Williams is determined to force Button to stand by his word and the 25-year-old faces a lengthy fight to extricate himself from a deal he signed last year after failing in a bid to quit BAR.

Nick Fry has warned Button he will take the fight to Williams without the vast resources of his current team to back him up, claiming BAR will have no part in negotiations to end the Williams contract.

BAR boss Fry said: “What we have always been consistent in saying is that we would like him here. It’s not really within our control particularly.

“Clearly from what’s been said he has a contract with Williams, that’s not one we have any knowledge of and clearly we haven’t seen it.

“It’s between Jenson and Williams. The two contract teams need to sort things out.

“We’ve made it clear we would love to have him here for the long run but we can’t really do a lot more than that.”

Fry is believed to have already signed a two-year contract with Ferrari driver Rubens Barrichello, who would provide BAR with an experienced grand prix winner to either replace Button or partner the Englishman in 2006.

That could leave Takuma Sato out in the cold and Fry has warned the Japanese driver he is running out of chances to show he deserves a third season in the car.

Sato finally scored his first point of the season in Hungary yesterday after a terrible start to the season and Fry is adamant BAR has no space for driver who cannot regularly deliver the goods.

“He drove well, ahead of the Renaults who were on the same tyres which was good for him,” added Fry, who expects confirmation of at least one of his 2006 drivers to come “within the next month or so“.

“His chance hasn’t gone already, far from it. Takuma needs to put in decent performances for the rest of the year but the door is still open.

“Lts of people have expressed interest in coming to the team which is really very encouraging. They can see the opportunity here just as Jenson can but as far as specifics, I can’t say anymore.

“We certainly need two drivers who can score points consistently and one of those at least has to have the potential to be the world champion.

“You don’t win the constructors’ championship by having one good one and one not so good one, or one that doesn’t score points. We need two drivers who can be up there at every race.”

Fry confirmed he will be allowed to replace Sato, even though the Japanese driver enjoys strong support from Honda, who own 45% of the team.

Sato has been powered by Honda throughout his career but Fry is convinced the Japanese giants will not stand in his way if the former Jordan man needs to be axed.

He said: “I don’t think any driver’s position is protected. We have to to have two drivers who can regularly score points, it’s as simple as that.

“In Hungary Takuma did a good job but clearly we are looking for him to do that in every race.”