International Desk: Uber will not be issued a new private hire licence, Transport for London (TfL) has said.
TfL concluded the ride-hailing app firm was not fit and proper to hold a London private hire operator licence.
It said it took the decision on the grounds of "public safety and security implications".
Confirming it would appeal against the decision, Uber said it showed the world "far from being open, London is closed to innovative companies".
Some 3.5 million passengers and 40,000 drivers use the Uber app in London.
In a statement, Uber said: "Transport for London and the mayor have caved in to a small number of people who want to restrict consumer choice."
Uber's general manager in London Tom Elvidge 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."
He said Uber operated in more than 600 cities around the world, including more than 40 towns and cities in the UK.
There had been growing speculation that the app could be banned from London.
Opponents of the firm claim it causes gridlocked roads and does not do enough to regulate its drivers.
TfL's concerns include Uber's approach to carrying out background checks on drivers and reporting serious criminal offences.
risingbd/Dhaka/September 22, 2017/A K Azad