Tommy Robinson has been imprisoned for violating the court for nine months.
The former leader of the English Defense League was found guilty last week of interfering with the lawsuit against a sexual care gang outside the Leeds Crown Court in May 201
Two judges from Old Bailey said his Facebook live video of defendants in the process have been encouraged to "Vigilante Action".
A Robinson name social media account called the phrase an "absolute joke" and said it was time to protest.
Robinson supporters, whose real name is Stephen Yaxley-Lennon, have been standing in front of the London court when news of his verdict reached them.
The crowd marched on old Bailey and shouted, "We want to get Tommy out," before some people began throwing bottles and cans at the police.
During the fall of 2018 in front of the Leeds Crown Court, there were reporting restrictions in place postponing the publication of details until the end of a series of related trials involving 29 defendants. However, the 36-year-old Robinson from Luton broadcast on May 25, 2018 footage from outside the court, while the jury in the second trial of The series thought about their judgment.
The video lasted one and a half hours and was viewed 250,000 times online after being live streamed on Facebook.
In a written judgment, Dame Victoria stated that Robinson claimed that his intention was to "denounce" the media for their behavior.
However, the judges found that he had encouraged others to "harass a defendant by finding him, knocking on his door, following him and watching him."
This created "a real risk that legal action would be severely hampered," she said.
Robinson was originally imprisoned for 13 months on the day of Facebook's broadcast, but was released two times months after winning an a ppeal.
The case was then remanded to Attorney General Geoffrey Cox, who announced in March this year that it was in the public interest to initiate a new trial.  The nine-month sentence served on Thursday includes six months for Leeds Crown Court's criminal offense last year and another three months for contempt of court after May 19, 2017, when a suspended sentence was imposed on Canterbury Crown Court.
Dame Victoria Sharp told Robinson on Thursday at the Old Bailey that the time had come when he was previously castigated for contempt, and his prison sentence was reduced to 19 weeks – half of which he served before he died is released.
Robinson's lawyer Richard Furlong overruled the court's appeal and was told 28 days to apply.
The Attorney General said the conviction clarified how serious the courts would be in scorning disputes, and urged everyone to think carefully about whether their social media posts could constitute contempt for the court.
What is a contempt of court?
There is a contempt for court law to ensure that people receive fair trials. The idea is that jurors can only be influenced by the evidence they hear in court.
The rules apply to everyone, from journalists to people posting comments on social media, and even to jurors.
When someone interferes in a trial, the defendants can go free and a new process may have to be carried out.
The maximum sentence for contempt of court is two years in prison, but it can also be punished with an unlimited sentence.
Contempt includes the publication of things that pose a significant risk of seriously affecting "active" criminal proceedings . The procedure becomes "active" when a suspect is arrested.
Someone could also be scorned by taking pictures or watching movies, recording what is said in court, or talking to a jury member about a case.
- Why is Tommy Robinson guilty of contempt?