Uber’s bid to keep operating in the biggest city in one of its most important global markets is about to enter its endgame.

Representatives for the company will appear before the Westminster magistrates court in London on Monday, June 25 to determine whether the company is “fit and proper” to operate in the city.

Transport for London (TfL), the city’s governing body for transit, failed to renew the ride-hailing service’s operating license in September. The company’s failure to report “serious criminal offences” by its drivers and its use of surreptitious tracking technology were among the reasons the license was rejected. Uber has roughly 3.5 million users in London, and about 40,000 drivers. It has been allowed to continue operating pending the court date.

To win its appeal, Uber will need to show that it’s made substantial changes to its operation after a scandal-packed 2017 culminated in the company’s founder and CEO Travis Kalanick being ousted and eventually replaced by the former CEO of Expedia, Dara Khosrowshahi. Over the last year, Khosrowshahi has worked to changed some of issues facing the company, introducing new safety features for riders, no longer demanding silence in corporate sexual-harassment cases, and committing to report serious driver offenses directly to the police.

Whether Khosrowshahi’s moves will be enough to sway magistrates is unclear. The hearing will reportedly last around three days, according to Business Insider, and it’s possible that the decision could still be appealed in a higher court.

But if Uber were to be finally rejected from London, it could have massive implications on the company’s future. As it lurches towards an IPO, losing its largest European market would be a troubling sign for potential investors, and perhaps an invitation for regulators in other regions to reconsider their relationship to the disruptive service.