Thousands of drivers working for ride-hailing and food delivery app Bolt have won a legal claim to be classed as workers in the UK rather than self-employed.
The ruling means drivers could be entitled to holiday pay and minimum wage, which lawyers said could lead to compensation worth more than £200m.
Bolt said it was reviewing its options, including grounds for appeal.
It pointed out that the findings of the Employment Tribunal were confined to drivers who were not on multiple ride-hailing apps.
About 10,000 current and former Bolt drivers took legal action against the Estonian-headquartered firm at a London employment tribunal.
They argued they were formally workers under British law.
Bolt said it had "always supported" the "choice" of drivers "to remain self-employed independent contractors".
But the tribunal found that "overwhelmingly, the power lies with Bolt".
"There is nothing in the relationship which demands, or even suggests, agency" on the part of the drivers, it said.
The tribunal added that "the supposed contract between the Bolt driver and the passenger is a fiction designed by Bolt – and in particular its lawyers – to defeat the argument that it has an employer/worker relationship with the driver".