Transport for London has today informed Uber that it will not be issued with a private hire operator licence.
The ride-hailing app will not be issued a new licence when its current one expires on 30 September.
TfL said it has concluded that "Uber London Limited is not fit and proper to hold a private hire operator licence".
Uber London boss Tom Elvidge said the "3.5m 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".
"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," he said.
"To defend the livelihoods of all those drivers, and the consumer choice of millions of Londoners who use our app, we intend to immediately challenge this in the courts."
Elvidge added that drivers who use Uber are licensed by Transport for London and have been through the same enhanced DBS background checks as black cab drivers.
"Our pioneering technology has gone further to enhance safety with every trip tracked and recorded by GPS," he continued.
"We have always followed TfL rules on reporting serious incidents and have a dedicated team who work closely with the Metropolitan Police. As we have already told TfL, an independent review has found that ‘greyball’ has never been used or considered in the UK for the purposes cited by TfL.
"Uber operates in more than 600 cities around the world, including more than 40 towns and cities here in the UK. This ban would show the world that, far from being open, London is closed to innovative companies who bring choice to consumers."
TfL 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".
These issues include:
Uber now has 21 days to appeal TfL's decision, and can continue to operate until any appeal processes have been exhausted.