Black Cab drivers under the United Cabbies Group Ltd (UCG) are challenging a decision by Chief Magistrate Emma Arbuthnot to reinstate Uber’s operating license in London in June last year.

The drivers claim the decision was “tainted by actual or apparent bias” and believe that the judge did not have legal powers to reinstate the license as Uber did not meet the criteria of being “fit and proper person”.

After the judge’s decision to approve the 15-month “probationary” license, a newspaper article alleged that there were financial links between her husband , Lord Arbuthnot, and Uber.

Her lawyers said that she was not aware of the connections but that she should have checked for any potential conflict of interest.

Robert Griffiths QC, representing United Cabbies told the court: “In our submission, there is a duty on a judge especially when dealing with high profile matters of this kind which have a significant element of public interest to check on whether there are any likely disqualifying interests which she should disclose to the parties on the basis that prima facie they may evidence a conflict of interest in respect of which the judge should recuse herself … Once the suspicion of bias has been created it colours the mind of even the fair minded and informed observer and the perception of continuing bias is perpetuated.”

After the article was released, a spokesperson for the judiciary said: Chief Magistrate Arbuthnot did not know the Qatar Investment Authority for which her husband had acted as an adviser was a shareholder in Uber or had any links with Uber.

“Lord Arbuthnot was not aware that the Qatar Investment Authority was a shareholder in Uber or that it had any links to Uber. This is the first time that such a connection has been brought to the Chief Magistrate’s attention.”

The spokesman added: “It is essential that judges not only are, but are seen to be, absolutely impartial.”

Philip Kolvin QC, counsel for Uber, told the court: “The attack on the judge’s impartiality and decision-making by non-parties to the appeal, who also happen to be trade competitors of Uber, is without substance and should be rejected.

“It is clear that the judge understood and applied the correct test, finding that Uber was, at the time of the decision, fit and proper to hold the licence.”

This the latest legal challenge the ride-hailing app is facing. The company is also answering to a $1.3billion tax lawsuit over employment rights of its drivers.

By Airport Pickups London