Around 100 Tommy Robinson supporters have gathered outside the Old Bailey where he is facing High Court judges over contempt of court charges.
He is accused of filming defendants in a criminal trial and broadcasting the footage on social media.
Supporters have been chanting “we want justice, we want justice now,” and “Tommy Robinson is a history maker”.
Speaking to journalists outside, Mr Robinson claimed he was being used as a "test case”.
“It's not me on trial today - it's your freedom as journalists,” he said, adding: “I have not broke [sic] any law.”
Many supporters attempted to follow him down a fenced-off walkway into court before being turned away by police.
The political activist, who campaigns against 'militant Islam', served two months in jail before being freed after a previous finding of contempt was overturned by the Court of Appeal in August 2018.
But Dame Victoria Sharp and Mr Justice Warby gave permission for fresh proceedings to be brought against him at a hearing in May.
Today and tomorrow at the Old Bailey, the High Court judges will hear the new application by the Attorney General Geoffrey Cox QC to commit Mr Robinson to prison.
During the hearing at the Old Bailey in June, Andrew Caldecott QC said the Attorney General considers Mr Robinson's conduct during the Leeds Crown Court trial to be of "great concern"
The barrister said it was "unfortunate" the history of the case was "prolonged" and accepted it had caused increased stress for Robinson.
The contempt hearing began 10.30am and is due to last for two days, during which Robinson is expected to give evidence.