Transport for London, the British capital's transport regulator, refused to renew Uber's private hire license on Friday.

Uber currently holds a license to operate in the city, but it will expire on Sept. 30. TfL holds private hire regulators to high standards in order to ensure passenger safety, and companies are not allowed to operate if not awarded a license.

"TfL has concluded that Uber London Limited is not fit and proper to hold a private hire operator licence," the regulator said in a statement. The company's "approach and conduct demonstrate a lack of corporate responsibility in relation to a number of issues which have potential public safety and security implications" means its license will not be renewed, it said.

TfL's decision is a fresh blow for Uber in what has been a year fraught with difficulties. The ride-hailing service has long struggled to meet local regulatory requirements as it has spread around the world, and has frequently faced opposition from the established taxi industry, including in London -- a city famous for its black cabs. But in 2017, the company has fought battles on multiple fronts, dealing with sexual harassment accusations and claims about company culture, which resulted in the resignation of CEO Travis Kalanick in June.

TfL listed its reasons for not renewing the license as follows:

Uber's approach to reporting serious criminal offences.
Uber's approach to how medical certificates are obtained.
Uber's approach to how Enhanced Disclosure and Barring Service (DBS) checks are obtained.
Uber's approach to explaining the use of Greyball in London - software that could be used to block regulatory bodies from gaining full access to the app and prevent officials from undertaking regulatory or law enforcement duties.
Uber has 21 days to appeal the decision and can continue to operate throughout the appeals process. The company plans to immediately appeal the decision in the courts, it said in an emailed statement.

"3.5 million Londoners who use our app, and more than 40,000 licensed drivers who rely on Uber to make a living, will be astounded by this decision," said Tom Elvidge, Uber's general manager in London. 

"By wanting to ban our app from the capital Transport for London and the Mayor have caved in to a small number of people who want to restrict consumer choice. If this decision stands, it will put more than 40,000 licensed drivers out of work and deprive Londoners of a convenient and affordable form of transport."

The Mayor of London, Sadiq Khan, tweeted in support of TfL's decision.

The established taxi industry in London has objected to Uber's presence in the capital loudly and frequently, occasionally staging physical protests in which black cabs block off city streets. The London Taxi Drivers' Association, the membership body that represents over 10,500 drivers across the city, praised TfL's decision on Friday, with General Secretary Steve McNamara saying it had "made the right call."

"Since it first came onto our streets Uber has broken the law, exploited its drivers and refused to take responsibility for the safety of passengers," he said in a statement. "We expect Uber will again embark on a spurious legal challenge against the Mayor and TfL, and we will urge the court to uphold this decision. 

"This immoral company has no place on London's streets," he added.

Rival ride-hailing app MyTaxi contacted customers immediately after the news broke offering 50 percent discount on journeys. "We are undercutting UberX on the news that they are not fit and proper to operate," it said.