Tommy Robinson filmed himself during an hour-long rant outside the court building which he streamed on Facebook Live and was viewed a quarter of a million times.
A judge who locked the right wing activist up for 13 months for contempt of court told him his actions may cause the sensitive case to be abandoned.
A strict order is currently in place temporarily banning publication or broadcasting details of the long-running case or anyone involved.
Media will be able to reveal details of the case later this year.
Click here for a short guide on contempt of court The Yorkshire Evening Post can now reveal details of Robinson's sentencing hearing which took place last Friday.
Robinson was arrested after naming defendants in the case, the charges they face and details of the allegations.
He also filmed defendants and confronted them as they were entering the building on Oxford Row.
The 35-year-old was held in the court cells before being taken into the court to face trial judge Geroffrey Marson, QC.
The judge explained why Robinson’s actions had been in contempt of court.
The judge said: “Nothing may occur which will prejudice the trial."
He added: “He was expressing his views. Everyone understands the right to freedom of speech but there are responsibilities and obligations.”
The video footage was played to the judge in court before he dealt with Robinson.
He said: “He was approximate to where defendants go in and approximate to where jurors go in.
“He was making a video. He was referring to this case.
“He referred to the charges that the defendants faced and some charges which are not proceeded against in relation to some defendants.”
The court heard the footage had received 250,000 views and a story about Robinson’s arrest was the lead article on a national newspaper website.
Judge Marson said: “Not only was it a very long video but I regard it as a serious aggravating feature that he was encouraging others to share it and it had been shared widely.
“That is the nature of the contempt.”