With more than 3.6 million people who use the service at least once every three months, London is one of Uber’s most lucrative global markets and biggest success stories outside the United States. The appeal removes a black eye as Mr. Khosrowshahi scales back in Asia and prepares for an initial public offering as early as next year.

But the company’s size also makes it politically risky for government officials to take its cars off the road. Uber says it provides millions of rides per week in London, and with roughly 45,000 drivers, its fleet nearly doubles the number of black cabs. More than 850,000 people signed a petition supporting Uber after the ban was announced last year.

Steve McNamara, general secretary of the Licensed Taxi Drivers’ Association, which represents about half the city’s 23,000 cabbies, criticized the city for allowing Uber to become “too big to fail.” The union lobbied to prevent Uber from regaining a license, and some of its members were in the audience during the hearings.

Uber’s experience in London tracks closely with its experience in other major cities. It gained popularity among customers who enjoyed the app’s convenience and comparatively low prices, and Uber’s strategy was to grow as quickly as possible so that it became indispensable.

But with its growth came criticism over poor treatment of drivers, inadequate passenger safety and harm to incumbent taxi industries. In September, frustrated by a raft of global scandals, London revoked Uber’s license. Transport for London, which regulates ride-hailing services in the city, said Uber was not a “fit and proper” business, a designation required to operate in Britain.

“We’ve had five years of a very difficult relationship where Uber has felt it didn’t require regulation,” Helen Chapman, Transport for London’s director of licensing, regulation and charging, said during testimony on Tuesday.