Hundreds of thousands of people have signed a petition calling for Transport for London to reverse its decision to strip Uber's licence in the capital.
Save Your Uber in London was set up on the Change.org website after it was announced the firm would not have its licence renewed whenit expires on September 30.
The petition had gained more than 400,000 signatures yesterday, just hours after being launched.
TfL said Uber was "not fit and proper" to operate in the capital and it took the decision on the grounds of "public safety and security implications".
But Uber, which is used by 3.5 million people and 40,000 drivers in London, hit back, saying it would appeal and claiming the move "would show the world that, far from being open, London is closed to innovative companies".
He went on: "Providing an innovative service must not be at the expense of customer safety and security.
"I fully support TfL's decision - it would be wrong if TfL continued to license Uber if there is any way that this could pose a threat to Londoners' safety and security."
Last month, Uber was accused by police of allowing a driver who sexually assaulted a passenger to strike again by not reporting the attack, along with other serious crimes.
