Jenson Button's Formula One future should be decided on Saturday at a hearing that will also determine several other drivers' hopes of racing next year.
However, the verdict may not be known until next week, with lawyers preparing for an all-day session in Milan to decide whether BAR or Williams has the recognised contract for the 24-year-old Briton.
Both teams lay claim to the hottest young driver this season, with Button already assured of third place in the championship after four second place finishes and six thirds.
Button made his Formula One debut with Williams in 2000 before moving to Benetton/Renault and then BAR at the end of the 2002 season.
BAR, the revelation of 2004 with second place in the constructors' championship virtually assured, looked to be the ideal home for Button but he shocked many in August when he said he was leaving.
Williams, who have also signed Australian Mark Webber, say BAR failed to exercise correctly an option on Button's services and have signed a two-year contract with the Briton. BAR say their contract is the only valid one.
Both sides, publicly at least, remain confident in a Contract Recognition Board (CRB) hearing expected to last for eight or nine hours.
The Swiss-based CRB is an independent tribunal backed by the governing body FIA to settle contract disputes in a notoriously quarrelsome sport. A driver cannot race without a contract recognised by the body.
OTHERS WAIT
Team boss Frank Williams will attend the hearing and a spokesman said a decision might not come until Monday.
"We have no concerns. Frank has said that when you go into a legal process you need to be prepared to lose but we are pretty confident," the spokesman added.
"I have always said that I want Jenson in the team and that has not changed," BAR's David Richards told the Times newspaper. "We want him to stay so we can go on from where we are to become a true challenger for Ferrari."
The fate of others hinges on the outcome.
Briton Anthony Davidson, the BAR test driver, is well placed to step into Button's shoes should Williams win.
However, Briton David Coulthard, winner of 13 races but without a job for next season after being ousted at McLaren by Colombian Juan Pablo Montoya, may also be in the frame.
Coulthard, 33, started his career at Williams in 1994 but that team has expressed little interest in taking him back.
The Scot appears to have run out of options unless one team or more folds and others are forced to run three cars next year to make up the numbers.
If BAR were to win, Williams will have a vacancy to fill and that could be Brazilian Antonio Pizzonia's big chance of a full-time comeback after standing in for injured German Ralf Schumacher this year.
Pizzonia has been acting as a test driver for Williams since being dropped by Jaguar, where he was Webber's team mate, last year and scored points in three of the four races he had in place of Ralf.
Other drivers watching the situation with interest include Germany's Nick Heidfeld, whose Jordan team are fighting for survival following Ford's decision to pull out of Formula One and sell engine supplier Cosworth.
