Tommy Robinson is guilty of contempt of court over broadcasting a trial on Facebook Live, High Court judges have ruled.
"The respondent's conduct amounted to a serious interference with the administration of justice," Dame Victoria Sharp, president of the Queen's Bench Division, said of the ruling.
Robinson, real name Stephen Yaxley-Lennon, was previously found guilty and sentenced to 13 months in jail in May 2018 for live-streaming outside a criminal trial in violation of UK law on reporting. However, the charge was quashed by an appeals court, with the 36-year-old released after spending two months behind bars.
The activist called Friday's ruling "the biggest case of 'one rule for Tommy' and one for everyone else," adding that "British justice system and the establishment stinks."
Robinson maintains that he had done nothing wrong, arguing that any information he had gleaned was in the public domain, and that the case against him is politically motivated.
In a statement, attorney general Geoffrey Cox said sentencing in the Robinson case would "take place at a later date."
Speaking to reporters after the hearing, Cox said he urged "everyone to think carefully about whether their social media posts could amount to contempt of court."
Under British law, contempt of court carries a penalty of up to two years in jail.
Robinson's supporters gathered outside the London court on Friday, chanting "Shame on you!" while pointing at the court. Speaking to reporters, Robinson claimed he had been convicted "for who I am, not what I have done."
The Robinson case became a national scandal after the activist live-streamed defendants on trial for the sexual exploitation of young English girls in 2017 in order to draw attention to their religious and ethnic backgrounds. During the live-stream, he cited demographic data about the number of Muslims and Pakistanis living in the UK, and compared it with their prevalence among grooming gangs.
Critics have accused Robinson of being a 'violent far-right racist', while supporters have argued that he is raising awareness of real social problems affecting Britain.