Anti-Islam campaigner Tommy Robinson encouraged “vigilante action” when he broadcast footage of men arriving in court to face child sex offences charges.
The UK high court said Robinson, whose real name is Stephen Yaxley-Lennon, was trying to agitate the public and was clearly interfering with the administration of justice.
Robinson is facing up to two years in jail after being found in contempt of court after breaching reporting restrictions in May 2018. He is due to be sentenced on Thursday.
“His words had a clear tendency to encourage unlawful physical or verbal aggression towards identifiable targets,” High Court judge Dame Victoria Sharp.
"Harassment of the kind he was describing could not be justified.
“There was plainly a real risk that the defendants awaiting jury verdicts would see themselves as at risk, feel intimidated, and that this would have a significant adverse impact on their ability to participate in the closing stages of the trial."
This would represent a “serious impediment” to the course of justice, it was found.
The court heard that Robinson encouraged those viewing his video, which lasted 90 minutes and was viewed 250,000 times, to harass, find, follow and knock on the door of the defendant he was filming.
"All of this has to be assessed in the context of the video as a whole, in which the respondent approves and encourages vigilante action,” Ms Sharp said.
"We are sure that what the respondent said in this passage will have been understood by a substantial number of viewers as an incitement to engage in harassment of the defendants."
Robinson’s defence team said he was facing the charges because of his reputation. A founder of the English Defence League, which he has since left, he has repeatedly criticised Muslims and been accused of racism.
He was originally jailed for 13 months last year after being found in contempt of court but his sentence was overturned after two months by the Court of Appeal in August 2018.
But the Attorney General said in March that proceedings would recommence because they were in the public interest.