Tommy Robinson supporters were pictured performing Nazi salutes at protests calling for the far-right criminal to be released from prison.
A man was filmed repeatedly making the gesture while holding a banner reading “f*** Islam” in Whitehall, London, while another Robinson supporter was photographed doing a Nazi salute in Belfast.
Demonstrations took place in several British cities and abroad in locations including New York and Melbourne on Saturday, seeing thousands of people calling for Robinson to be freed.
He has been jailed for 13 months after admitting committing contempt of court by live streaming details of a trial that was subject to blanket reporting restrictions at Leeds Crown Court.
A judge initially banned reporting on Robinson’s imprisonment but the order was lifted following a challenge by The Independent and local media.
Robinson, who was jailed under his real name Stephen Yaxley-Lennon, had already been handed a suspended sentence for the same crime and was told he could have caused the trial to collapse.
In London, nine men were arrested after protesters attacked police with metal crowd barriers, road signs and missiles, injuring five officers.
A 26-year-old man has been charged with possession of an offensive weapon and eight others have been released under investigation.
A 50-year-old man with a flare was arrested for explosives offences, another suspect was arrested for possession of cannabis and breach of the peace, while six suspects were detained for public order offences.
A spokesperson for Scotland Yard said: “The Met’s public order investigations team has launched an investigation and are collating CCTV from the area. Enquiries continue.”
The force declined to comment further on the treatment of its officers – who appeared to be vastly outnumbered – or the reasons behind the force’s apparent lack resources on the day.
Footage showed unarmed police being chased by a large crowd chanting “scum” near Trafalgar Square, while protesters had earlier overrun and vandalised a sightseeing bus.
American tourists filmed officers retreating down a side street from their hotel room while protesters following them chanted and threw traffic cones and other objects.
Michael Bradley, a coordinator for Stand Up to Racism who attended the rally, said Robinson’s supporters repeatedly tried to break through barriers to attack counter-protesters before turning on police.
He said violence had been mounting through a series of protests purporting to support free speech that have increased in frequency since members of the ethno-nationalist Generation Identity group and American activists were blocked from entering the UK.
“There were loads of people doing Nazi salutes during the day,” he told The Independent.
“Most of the fascist right in Britain were on that demonstration… at all these demonstrations have been clashes and they target anti-racist organisations, so clearly as it’s gone on it’s got more violent.
“I think they see Robinson as the way to weld the movement together.”
Nick Ryan, the director of communications at Hope Not Hate, said the violence seen on Saturday could indicate a return to racist street movements that petered out over the past decade.
He said that policing protests by Robinson’s English Defence League (EDL) had cost British forces more than £10m in public money between 2009 and 2013 and the situation appeared to be escalating once more.
“There has been an attempt to marry up the street element with the online agitating,” he told The Independent, noting the rise of the Football Lads Alliance, which claims to oppose terror.
“Normally things on the far right fall apart because there are a lot of internal disputes but [Robinson’s imprisonment] is acting as a lightning rod for different groups to come together.
“What’s disturbing is that these groups who would normally support strong law and order don’t apply it to their own side.
“They’re co-opting the free speech mantle but it’s a one-way street, as long as it applies to them.”
Mr Ryan said more “free Tommy” protests were being planned and that it was unclear if the movement would fade or grow as his sentence continues.
“There is an irony to people demanding free speech at a march in the heart of Westminster,” he added.
“Beyond blokes going out boozed up and wanting a fight, I’m sure there are minds behind this that have a full strategy.”
Gerard Batten, the leader of Ukip, was among high profile speakers at the London rally and later condemned violence committed by “a few idiots and provocateurs”.
Calling Robinson a “political prisoner”, he told the crowd they had to choose whether to “submit to or resist” Islam.
“Are you going to resist?” he asked, to shouts of “yes”.
Geert Wilders, the leader of the Dutch opposition and far-right Party for Freedom, also spoke in Robinson’s support, as did the failed Ukip leadership candidate and For Britain group leader Anne Marie Waters.
The speeches were presided over by former Breitbart London editor Raheem Kassam, who read a message from his former boss Steve Bannon expressing support for Robinson.
Mr Bannon served as the White House chief strategist for the first seven months of Donald Trump’s term and is among the high profile figures in the US alt-right who have been amplifying Robinson’s message.
The EDL founder has also been capitalising on increased coordination with far-right figures in the pan-European Generation Identity movement after raising his profile by becoming a correspondent for the Canadian far-right website Rebel Media.
He has been incorrectly described as a “journalist” by some supporters, who characterise his imprisonment as an attack on freedom of speech.
Robinson has previously been jailed for mortgage fraud and appears to earn money primarily through supporters’ donations made through his website.
He has been permanently banned from Twitter and had videos removed from YouTube, but remained active on Facebook until his arrest at Leeds Crown Court on 25 May.
The Finsbury Park terror attack trial heard Robinson’s posts had inspired Darren Osborne to plough a van into Muslims, killing a grandfather after Ramadan prayers last June.