Tommy Robinson faces a long spell in segregation for his own protection after being jailed for 18 months for contempt of court.
The 41-year-old, whose real name is Stephen Yaxley-Lennon, admitted 10 breaches of a 2021 High Court order barring him from repeating libellous allegations against Syrian refugee Jamal Hijazi, who had successfully sued him.
The claims were aired in Robinsons film, Silenced, which was funded by Infowars - an American company founded by notorious conspiracy theorist Alex Jones.
Mr Justice Johnson said he would not suspend the sentence due to the seriousness of the offending and because the defendant has a history of poor compliance with court orders. He said the activist would be released half way through his term.
When he was last imprisoned for contempt, Robinson was kept in complete isolation for his own protection, his lawyer told todays court hearing - a precaution that may be repeated this time around.
Tommy Robinson at Woolwich Crown Court today as he pleads guilty to contempt
The activist, whose real name is Stephen Yaxley-Lennon, had admitted contempt of court
Mr Justice Johnson said he would not suspend the sentence due to the seriousness of the offending and because the defendant has a history of poor compliance with court orders
Former prison governor Ian Acheson said the decision where to put Robinson would be a real headache for the prison service.
You have someone who would not be considered an escape risk, hasnt been convicted for a crime of violence and has been found guilty of breaking a civil restriction, so normally he could be put in open conditions, he said.
But open prisons are very unsupervised and that could leave Robinson at risk of being attacked.
There is also a risk of his presence disrupting the good order of the prison due to the presence of people who might sympathise with him - particularly as the far-right push the narrative of the rioters being political prisoners.
Mr Acheson said Robinson could be at risk of attack from people who dont like him and consider him a racist, as well as from convicts who sympathise with Islamic extremists.
And he warned the infiltration of organised criminals into the prison system meant there could even be the risk of a bounty being put on his head.
Mr Acheson said the decision about whether to segregate Robinson from other prisoners would be taken by prison bosses but he believed this was necessary.
I think the consequences of Robinson being injured or assaulted in prison are so serious due to the risk of inflaming the risk of civil disorder outside that the system ought to segregate him in closed conditions, he added.
As the sentence was handed down earlier today, Robinson - in a grey suit and white shirt - glanced and nodded at his supporters in the public gallery, and rocked slightly in the dock, with his hands clasped in front of him.
His supporters packed the public gallery and stood outside the court, with some in court waving and blowing kisses to Robinson as he led away from the dock.
In 2010 - when he was last jailed for contempt of course, Robinson cried on a Sky TV documentary as he spoke about spending 10 weeks in solitary confinement in HMP Belmarsh.
Mr Justice Johnson told the court: In a democratic society underpinned by rule of law, court injunctions must be obeyed. They (defendants) are entitled to disagree with the result, they are not entitled to disobey the court injunction.
Nobody is above the law, nobody can pick and choose which laws they obey. They are not entitled to set themselves up as a judge in their own cause… Otherwise rule of law would break down.
The defendant was well aware of the terms of the injunction and the consequences of breaching it. The breaches were not accidental or negligent or merely reckless. Each was a planned, direct and flagrant breach of the court order.
He described the breaches as sophisticated and designed to maximise coverage – with one video reportedly being seen 44 million times.
Robinson had been barred from repeating false allegations against Jamal Hijazi, after the then-schoolboy successfully sued him for libel.
Supporters of the far-right activist gathered outside Woolwich Crown Court this morning
A man wearing an English flag looks on as supporters of Robinson gather outside Woolwich Crown Court
Mr Justice Johnson acknowledged Robinson initially complied with the 2021 injunction until around February 2023, when he was asked about the Hijazi case in an interview.
But the judge said: The primary harm caused by each breach is the corrosive effect it has on the administration of justice.
He said the fact Robinson continued to host the offending video on his social media further signalled his determination to defy the injunction.
He said: The defendant has not shown any remorse for breaches of the order, it would be surprising if he had done so.
The defendant has not shown any inclination to comply with the injunction in the future. All of his actions so far suggest he regards himself as above the law.
(He) continues to maintain material on his social media account in breach of the injunction, even as this hearing takes place.
The judge said Robinson could receive a four-month reduction in his sentence if he showed contrition and removed the video from his social media, while making efforts to have it taken down elsewhere.
The activists contempt breaches include broadcasting a film titled Silenced, at a demonstration in Trafalgar Square in July - one of six actions claimed to have breached the injunction between June and July this year.
The film is also pinned to the top of his X account.
Sasha Wass KC, for Robinson, told the court earlier today that the films production was funded by Infowars, a company run by American Alex Jones, who has claimed that the 2012 Sandy Hook school massacre was a hoax.
Far-right protesters walk through London on Saturday in a rally endorsed by Robinson
Mr Hijazi successfully sued Robinson after the then-schoolboy was assaulted at Almondbury Community School in Huddersfield, West Yorkshire, in October 2018.
Robinson made false claims after a clip of the incident went viral, including about Mr Hijazi attacking girls in his school, leading to the libel case.
Mr Justice Nicklin ordered Robinson to pay Mr Hijazi £100,000 in damages and his legal costs, as well as making the injunction preventing Robinson from repeating the allegations he made against the then-teenager.
In a separate matter, Robinson has also been charged with failing to provide the PIN to his mobile phone under Schedule 7 of the Terrorism Act.
It follows his arrest in July at a port in Kent where he was accused of failing to comply with demands from police.
Under schedule 7 of the Terrorism Act, officers are allowed to stop anyone passing through a UK port to determine whether they may be involved or concerned in the commission, preparation or instigation of acts of terrorism.
He will appear at Westminster Magistrates Court on November 13 in relation to the latter incident.
Robinson posted a video of himself arriving at Luton Airport on October 20 and said he was surprised he had not been arrested.
He then handed himself in to police, accompanied by a large entourage and many supporters. He was remanded in custody ahead of todays hearing.
On Saturday, thousands of his supporters gathered in central London for a protest which Robinson missed after he was remanded.
Demonstrators carried placards reading Two tier Keir fuelled the riots - a reference to the widespread disorder across the UK this summer amid anger over the Southport dance class massacre, after misinformation on social media wrongly identified the suspected killer as a Muslim migrant - and chanted We want Tommy out as they headed from Victoria station to Parliament Square.
Two people were arrested from the far-right march - one for a racially aggravated public order offence and a second for breach of the Public Order Act conditions.
A further pair were arrested for assault at the Stand Up To Racism counter protest.
Key landmarks close to the march routes - including the Cenotaph and the statue of Winston Churchill in Parliament Square - were sealed off from the public amid concerns about damage.
A young man holds a picture of Donald Trump as he marches through London as part of the crowd
Counter-protesters from Stand Up To Racism also came out on the streets of London
Aidan Eardley KC, representing the Solicitor General who brought the case, said a resolution had been reached over the allegations.
Mr Eardley said: The background to this matter starts in October 2018. Jamal Hijazi was a 15-year-old schoolboy, recently arrived in the UK from Syria.
He was attacked by a fellow pupil. That incident was filmed and published online. That film went viral. It attracted a great deal of commentary and suggests Jamal Hijazi was the victim, and the motivation was racial.
Mr Yaxley-Lennon took an interest in that, and according to him, got evidence that suggests Mr Hijazi was a violent bully at school and was getting his comeuppance.
He said Robinson posted his videos explaining this on his Facebook account, which had around 1 million followers at the time.
Mr Eardley said Robinson was taken to court for libel by the schoolboy, but cited a defence of truth.
The judge found Robinson did not prove his case sufficiently to meet the legal threshold.
Mr Eardley said the Silenced film was a substantial piece of work lasting around 90 minutes, entirely devoted to the Hijazi case.