Uber has survived a high court challenge to its licence to operate in London, after judges rejected claims of bias brought by a group of black cab drivers.

In a crowdfunded legal bid, drivers had argued that Uber’s 15-month permit was decided by a magistrate with conflicts of interest, making her ruling “tainted by actual or apparent bias”.

The United Cabbies group (UCG), representing black cab drivers in the capital, hoped to overturn the licence granted on appeal by chief magistrate Emma Arbuthnot on a “probationary” basis last June. Transport for London (TfL) had refused to renew Uber’s licence when it expired in September 2017, citing safety concerns.

Arbuthnot since said she would not hear any further cases involving Uber after reports emerged alleging financial connections between the firm and her husband, Lord Arbuthnot.

At a hearing in London earlier this month, UCG lawyers argued that the judge should have checked for any potential conflicts of interest.

However, their case was dismissed by the lord chief justice Lord Burnett and Mr Justice Supperstone on Tuesday.

Burnett said in his ruling: “Having ascertained all the circumstances bearing on the suggestion that the judge was biased, we consider that those circumstances would not lead a fair-minded and informed observer to conclude that there was a real possibility that the judge was biased in this case.”

He said that the “tenuous connections unearthed” by UCG fell “well short of evidence that would begin to give a fair-minded observer even pause for thought”.

Uber has put in an application for costs, which could see drivers having to find another £150-200k on top of their own legal costs, including £48k costs for TfL. The action was brought after a crowdfunding campaign among black cab drivers.

The London Taxi Drivers Association, an interested party, will also be liable for 10-20% of the costs.

Uber’s licence renewal had originally been rejected by TfL over concerns such as a failure to report allegations of assaults on passengers to police, how it conducted background checks on drivers, and how the app had been modified in the US to thwart regulators.

But after pledges to reform from chief executive Dara Khosrowshahi, and the implementation of safeguards such as a 24-hour phone helpline, Uber did enough to convince Arbuthnot that the firm had changed sufficiently to give it a short licence, with stringent conditions – although she remained critical of the firm in her ruling. The licence is due to expire in September.