Tommy Robinson has been arrested under anti-terror laws, according to his supporters, after a protest at which a film was allegedly screened in contempt of court.
His detention was made public in a post on his verified X account and follows a march led by Mr Robinson and a counter-protest in central London on Saturday which attracted thousands of people.
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.
Mr 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 his X account on Sunday said: “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.”
The Metropolitan Police said there was “no Met involvement” in reference to the post about Mr Robinson’s arrest.
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.”