LONDON - London deemed Uber unfit to run a taxi service on Friday and stripped it of its license to operate from the end of next week in a major blow to the US firm and 3.5 million users in one of the world's wealthiest cities.The capital's transport regulator said the Silicon Valley technology giant's approach and conduct was not fit and proper to hold a private vehicle hire license and it would not be renewed when it expires on Sept. 30.Uber, which has 40,000 drivers working in the capital, said it would contest the decision. Regulator Transport for London (TfL) said it would let Uber operate until the appeals process is exhausted, which could take months."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," TfL said.Specifically, TfL cited Uber's approach to reporting serious criminal offenses, background checks on drivers and software called Greyball that could be used to block regulators from gaining full access to the app."Transport for London and the Mayor have caved in to a small number of people who want to restrict consumer choice," said Tom Elvidge, Uber's general manager in London. "We intend to immediately challenge this in the courts."An online petition against the decision had gathered more than 200,000 signatures within five hours.