London transport authorities said Friday they would not renew Uber's licence to operate in the city when it expires, due to public safety concerns, although the US-based ride-hailing app has said it will appeal.

Transport for London said the conduct of Uber, which has around 40,000 drivers and 3.5 million customers in the British capital, had raised concerns.

"TfL has concluded that Uber London Limited is not fit and proper to hold a private hire operator licence," it said in a statement.

It said Uber'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".

The licence expires on September 30 but Uber has 21 days to appeal the decision, and can continue to operate until the process has been exhausted.

London joins other cities such as New Delhi, Mumbai and Cape Town in not granting a licence and the decision adds to woes for Uber's new boss Dara Khosrowshahi following a string of controversies.

- 'London is closed' -

The company hit back saying the decision would "show the world that, far from being open, London is closed to innovative companies.

"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," the company said in a statement.

Around 200,000 people had signed an online petition by the company to reverse the decision and "defend the livelihoods of 40,000 drivers".

TfL highlighted the company's approach to reporting serious criminal offences and to obtaining criminal record checks for drivers as factors in its decision.

The company came under scrutiny in Britain after it emerged that dozens of rape and sexual assault claims had been made against their drivers and when one of their drivers used his vehicle in a recent terror attack on Buckingham Palace.

It also questioned the process through which drivers obtain their medical certificates and the practice of "greyballing", when the company uses a fake version of its app to fool regulators in cities in which it is banned.

- 'No place in London' -

Mayor of London Sadiq Khan said he fully supported the decision.

"I want London to be at the forefront of innovation and new technology and to be a natural home for exciting new companies that help Londoners by providing a better and more affordable service," he said.

"However, all companies in London must play by the rules and adhere to the high standards we expect -- particularly when it comes to the safety of customers.

US Commerce Secretary Wilbur Ross said the decision was "not very justified", while acknowledging that the Uber issue is not one he is responsible for.

"It looks pretty obvious that they're becoming discriminated against because they're worried our companies are so much stronger than the ones in Europe itself," Ross said on CNBC.

London's traditional "black cab" drivers have long campaigned against the service, and welcomed Friday's decision.

Licensed Taxi Drivers' Association said: "The Mayor has made the right call not to relicense Uber," said Steve McNamara, general secretary of the Licensed Taxi Drivers' Association.

"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."

The Sun newspaper reported last year that 32 sexual assault claims were made against Uber drivers in 2015/16, more than a fifth of all claims against taxi drivers filed to British police forces.

Uber, which operates in hundreds of cities and more than 80 countries, last month announced that it hired former Expedia boss Khosrowshahi as its new chief executive in an attempt to steer the ride-sharing service away from the string of controversies it has faced in the past year.

Dents to Uber's image include a visit by executives to a South Korean escort-karaoke bar, an attempt to dig up dirt on journalists covering the company, and the mishandling of medical records from a woman raped in India after hailing an Uber ride.