Uber submitted a court appeal on Friday to overturn a decision by London’s transport regulator that stripped the taxi app of its operating license in one of its most important markets.

Transport for London (TfL) shocked the Silicon Valley firm last month by deeming it unfit to run a taxi service and refusing to renew its license, citing its approach to reporting serious criminal offences and background checks on drivers.

Friday’s filing is a short notification of Uber’s intention to appeal rather than the detailed grounds. A hearing is likely to take place on December 11, a spokesman at Britain’s Judicial Office told Reuters.

Uber, criticized by London Mayor Sadiq Khan for employing an “army of lawyers”, said that it hoped to keep talking to TfL to find a way forward.

“While we have today filed our appeal so that Londoners can continue using our app, we hope to continue having constructive discussions with Transport for London,” an Uber spokesman said.

“As our new CEO has said, we are determined to make things right.”

ALSO READ: Uber trains women to drive in Saudi Arabia

New global Chief Executive Dara Khosrowshahi met TfL Commissioner Mike Brown for talks earlier this month, which both sides said were “constructive” as the $70-billion firm tries to repair its relationship with the regulator. 

First stage of a legal process 
The appeal was submitted to Westminster Magistrates’ Court on Friday in the first stage of a legal process which could take months or years to reach a conclusion.

Uber’s 40,000 drivers in the British capital will be able to continue operating until the appeals process is exhausted.

Khan, a politician from the opposition Labour Party who is also chairman of TfL, has long criticized Uber’s British management and backed the regulator’s decision on Thursday.

“The courts now will consider the appeal from Uber and of course TfL will defend the decision they made,” he said during a monthly question time session.