London’s transport regulator, Transport for London (TfL), has refused to grant Uber a new license in the city. TfL had been extending Uber’s license to operate in London in recent months, after the ride sharing company lost its license in 2017. TfL originally revoked Uber’s license citing Uber’s approach to serious criminal offences, medical certificates, disclosure and barring checks, and the company’s use of its Greyball software that TfL said blocked regulatory bodies from gaining full access to Uber’s app for law enforcement duties.

TfL now says it has identified a “pattern of failures” by Uber, including breaches that placed passengers at risk. “Despite addressing some of these issues, TfL does not have confidence that similar issues will not reoccur in the future, which has led it to conclude that the company is not fit and proper at this time,” says a TfL spokesperson. One particular issue that was identified was a change in Uber’s system that “allowed unauthorised drivers to upload their photos to other Uber driver accounts.”

This enabled other Uber drivers to pick up passengers as if they were booked with the original driver, and TfL says this occurred during at least 14,000 trips. “This means all the journeys were uninsured and some passenger journeys took place with unlicensed drivers, one of which had previously had their licence revoked by TfL,” says a TfL spokesperson. A similar issue allowed suspended drivers to create an Uber account and take passengers on trips.

London’s mayor, Sadiq Khan, also backed TfL’s decision today. I know this decision may be unpopular with Uber users but their safety is the paramount concern,” said Khan in a statement on Twitter. “Regulations are there to keep Londoners safe, and fully complying with TfL’s strict standards is essential if private hire operators want a license to operate in London.”

TfL is now revoking Uber’s license in London, and the firm will have 21 days to appeal the decision. Much like last time, Uber will be able to continue to operate in the city throughout the appeal, which will involve the ride sharing company appealing to a magistrates court to demonstrate its app is safe for passengers. “If they do appeal, Uber can continue to operate and we will closely scrutinize the company to ensure the management has robust controls in place to ensure safety is not compromised during any changes to the app,” explains a TfL spokesperson.

Uber previously won an appeal to continue operating in London, and was granted a probationary 15-month license last year. This license expired in September, and TfL provided a two-month extension until today. Uber is planning to appeal this latest ban. “TfL’s decision not to renew Uber’s licence in London is extraordinary and wrong,” says Jamie Heywood, Uber’s regional general manager for Northern & Eastern Europe. “We have fundamentally changed our business over the last two years and are setting the standard on safety. TfL found us to be a fit and proper operator just two months ago, and we continue to go above and beyond.”

Update November 25th, 5:50AM ET: Article updated with comment from Uber.