The UK capital's public transport network operator TfL has said that ride-sharing service Uber will not be issued with a private hire operator license after its current license expires on September 30.

TfL says "Uber's approach and conduct demonstrate a lack of corporate responsibility" in relation to issues such as "reporting serious criminal offences" or "its approach to how medical certificates are obtained."

Uber has announced it will appeal the decision. "Transport for London and the Mayor have caved in to a small number of people who want to restrict consumer choice," Uber said in a statement.

"We intend to immediately challenge this in the courts." Uber said that more than 40,000 people would be out of work if the license is revoked and that its background checks are just as stringent as those for London's famous black cab drivers.

TfL stressed that Uber can continue to operate "until any appeal processes have been exhausted."

London's mayor, Sadiq Khan, supports the decision, saying any operator in the city "needs to play by the rules."

Providing an innovative service must not be at the expense of Londoners safety. My response to @TfL's Uber decision. https://t.co/iEUal9VLU3 pic.twitter.com/B9V0mEKrWr

— Sadiq Khan (@SadiqKhan) September 22, 2017

In a tweet, he stressed that he is in favor of innovation and new technology but that it must "not be at the expense of customer safety and security."

Uber willing to make concessions

Later, Uber admitted that it would be willing to make concessions in order to keep its license.

"While we haven't been asked to make any changes, we'd like to know what we can do," Uber's London general manager, Tom Elvidge, told the Sunday Times.

The TfL has declined to make an official comment on Elvidge's statement, but the newspaper quotes a source close to the organization that said talks were possible. The transport body has said that Uber has failed to report serious criminal offenses, conduct comprehensive background checks on drivers and keep up with safety controls.

According to the ride-sharing firm, 20,000 of its drivers have e-mailed Mayor Khan in defense of their livelihoods.