Supreme Court justices are set to decide whether Uber drivers should be classed as workers.
Seven justices considered the latest round of a long-running fight between Uber operating companies and drivers at a virtual Supreme Court hearing in July.
They are due to deliver a ruling on Friday.
Uber operating companies, who say drivers are not workers, appealed to the Supreme Court after losing three earlier rounds of the fight.
An employment tribunal ruled in 2016 that Uber drivers were workers, and were entitled to workers’ rights.
That ruling was upheld by an employment appeal tribunal, and by Court of Appeal judges.
Lawyers representing Uber operating companies told Supreme Court justices that the employment tribunal ruling was wrong.
They said drivers did not “undertake to work” for Uber but were “independent, third party contractors”.
But lawyers representing drivers said the tribunal was entitled to conclude that drivers were working.
They said Uber’s appeal should be dismissed.
A law firm enlisted by the GMB union to represent Uber drivers says drivers will be entitled to compensation for lost pay, if Uber loses in the Supreme Court.
Leigh Day lawyers think tens of thousands of Uber drivers could be entitled to an average of £12,000 each.
A Leigh Day spokeswoman said, if Uber lost the Supreme Court fight, the case would return to an employment tribunal, for decisions to be made on how much compensation drivers should get.