By Andrew Benson Motorsport editor at Silverstone

Button is thought to want a salary increase

Jenson Button is poised to pledge his long-term future to BAR.

Button, who is under contract with the team until the end of next year despite reports to the contrary, is in talks aimed at extending his deal until 2007.

"We have a few things to sort out, but I hope to be with BAR a lot longer," said the Briton, who is third in the championship ahead of the British GP.

Team boss David Richards said: "I want to make it firm and have clear long-term rather than year-at-a-time goals."

Richards added: "Jenson has confirmed my belief that he is a future world champion. This is a team with huge ambition moving forward."

Williams had initially targeted Button for next year, but he has a clause in his BAR contract that states he cannot leave if the team are sixth or higher in the constructors' championship by this weekend.

They lie third, behind Ferrari and Renault.

We're not as happy [with the car] as were at the test here a short while ago - we've got some more work to do, I think Geoff Willis BAR technical director

Richards and Button are understood to have had a disagreement about money, with the driver's management arguing for a salary increase if he was to stay for 2005.

But the two are now in talks about extending their partnership to end of 2007.

BAR have had an impressive season in 2004, ending a cycle of years of underachievement and over-spending.

With Renault, they have consistently been Ferrari's main challengers.

However, the team are concerned that the car has not performed as well as expected in recent races.

Technical director Geoff Willis said that the team were "reasonably happy" with their car after Friday practice.

"But we're not as happy as were at the test here a short while ago. We've got some more work to do, I think."