Tommy Robinsonhas been 'arrested under counter terrorism law', according to a post on his verified social media accounts.
The Metropolitan Police has said it 'does not recognise' the claims and there is 'no Met involvement'. MailOnline has been unable to independently verify the claims made in the post.
It comes after far right activist was warned he could be face prison for after screening a banned film to thousands of his supporters at a Trafalgar Square rally yesterday.
A complaint was later made over a film which was allegedly shown to the crowd in breach of a High Court order, with police saying officers were making further inquiries.
Robinson, whose real name is Stephen Yaxley-Lennon, also on Saturday afternoon posted a one hour 45 minute film on X, in which he said he had previously avoided publishing the video because he was 'scared'.
A post on Tommy Robinson's social media account claims he has been arrested. Pictured: Tommy Robinson at a rally in Trafalgar Square on Saturday
A post on Tommy Robinson's X account claimed the former English Defence League leader had been detained under anti-terrorism laws
A post put out by his official account on X, formerly known as Twitter, this afternoon said: 'EMERGENCY ADMIN POST - PLEASE SHARE FAR AND WIDE!!!!
'We can confirm that Tommy Robinson has been detained by Police using powers afforded to them under the Terrorism Act 2000.
'That's right, you read that correctly, Tommy is being held by Police using counter terrorism legislation.
'We will update you as and when we can.'
MailOnline has been unable to independently confirm that Robinson has been arrested.
The Metropolitan Police has told MailOnline is 'does not recognise' the claims made in the post and that if he had been taken into custody there was 'no Met involvement'.
The former English Defence League leader made the claim a day after thousands of his supporters marched through central London before gathering in Trafalgar Square for his 'Uniting The Kingdom' rally.
The event, billed by the 41-year-old as the 'biggest patriotic rally the UK has ever seen', saw Robinson and other members of the far-right give speeches.
The crowd was also shown a documentary called Silenced - about a Syrian refugee Jamal Hijazi being assaulted by another pupil in the playground at Almondbury Community School in Huddersfield - despite a judge previously calling it contempt of court.
Mr Hijazi successfully sued Robinson in 2021 for libel after false claims were made about him, including that the then-teenager had attacked girls in his school. Robinson was ordered to pay him £100,000 in damages plus costs.
After the screening yesterday Robinson had challenged the authorities to 'take him to court'.
The event, called 'Uniting The Kingdom', was organised by former English Defence League leader Tommy Robinson, pictured yesterday
Thousands of people gathered in Trafalgar Square waving British flags for the rally on Saturday
People attending the event organised by Tommy Robinson gathered outside the Royal Courts of Justice on Saturday morning
Posting on his X account, he wrote: 'I'll be jailed for two years for showing the inconceivable truth.'
He was already due before the High Court on Tuesday accused of contempt for making the film.
Robinson screened it at the rally despite the injunction banning him from repeating the claims made in it.
In response to a complaint about the film on X on Saturday evening, the Met said: 'We did not know what films would be shown during the event. Organisers of protests are not required to share those details in advance. There is no power for us to compel them to do so.
'Officers on duty for the event couldn't reasonably have been aware of civil proceedings ongoing in relation to a particular film, but having now been made aware we're making further inquiries to determine what action we need to take.'
On Saturday night the force revealed that nine people had been arrested in relation to the event, which saw hundreds of counter-demonstrators flood the streets at the same time.
Among those detained were two men taken into custody after an anti-racism protester was attacked as the counter-rally, organised by Stand Up To Racism, marched towards Whitehall.
A St George's flag with the words 'stop the boats' and 'do it for our kids future' was waved aloft in Trafalgar Square
British and English flags flew in the air as people at Trafalgar Square listened to a speech by Tommy Robinson
The victim received a head injury was taken to hospital after the incident in Victoria Embankment Gardens.
Police saying the pair - who are believed to have been part of the Tommy Robinson protest - had been taken into custody on suspicion of committing grievous bodily harm (GBH).
Four people were arrested outside a pub in Whitehall on suspicion of assault on emergency workers. Four Met officers were assaulted.
One man was also held on suspicion of criminal damage and a racially aggravated public order offence after allegedly snapping a Palestinian flag and making a racially abusive remark, while another was arrested on suspicion of assaulting an emergency worker after a police officer was kicked, the force said.
The police had already used powers under the Public Order Act to try to keep the opposing groups apart amid fears of serious disruption.
