The rejection is the latest set-back to the firm’s operations in London, which have been targeted by protests from traditional black cab drivers to previous licence suspensions.
But TfL said on Monday there were a “pattern of failures”, including the use of unauthorised drivers on other drivers’ accounts, allowing them to pick up passengers.
The transport authority said this happened at least 14,000 times, endangering users, as it invalidated insurance. Some trips took place with unlicensed, suspended or dismissed drivers.
TfL said it recognised steps the company had taken to address such issues but was concerned about the ease with which its checks and balances could be manipulated.
Legislation allows Uber 21 days to appeal and the company can continue to operate during this time.
Helen Chapman, director of licensing, regulation and charging at TfL, said safety was its “absolute top priority” and the infringements were “unacceptable”.
“It is clearly concerning that these issues arose, but it is also concerning that we cannot be confident that similar issues won’t happen again in future,” she added.
There was no immediate comment from Uber, which will have to demonstrate on appeal that it has put in place sufficient measures to eliminate risks to passengers.
Mayor of London, Sadiq Khan, said he backed the decision. He added he recognises the decision would be unpopular but that companies need to play by the rules.
“Keeping Londoners safe is my absolute number-one priority, and TfL have identified a pattern of failure by Uber that has directly put passengers’ safety at risk,” he said.
© Agence France-Presse