More than 100,000 people have joined a march in central London organised by far-right activist Tommy Robinson, with a counter-protest by anti-racism campaigners also taking place, News.az reports citing BBC.
Protesters forming the "Unite the Kingdom" rally gathered in Whitehall where they heard a series of speeches including from tech billionaire Elon Musk, via videolink.
The Metropolitan Police said nine people had been arrested for various offences and added there had been "significant aggression", with some officers being "attacked with projectiles" .
Meanwhile, the Met estimates about 5,000 people have joined the nearby counter-protest organised by Stand Up To Racism (SUTR).
The Met said it had borrowed 500 officers from other forces for the day, with police vans from Leicestershire, Nottinghamshire and Devon and Cornwall.
PA Media / The Met Police deployed extra officers with protective equipment as well as police horses in central London
One side waved placards saying "refugees welcome. Stop the far right", and the other Unite the Kingdom group flew Union and St George's flags.
The Met said some officers had been attacked while trying to keep the groups apart.
"Officers are having to intervene in multiple locations to stop Unite the Kingdom protesters trying to access sterile areas, breach police cordons or get to opposing groups," the Met said on X.
"A number of officers have been assaulted."
PA Media / The Met Police estimated around 110,000 were in Whitehall for the Tommy Robinson event and 5,000 for the counter-protest
Some officers could be seen taking out batons at about 16:25 as they tried to push back Robinson supporters who had gathered near Trafalgar Square.
Projectiles - including glass bottles, metal poles and beer cans - have been thrown at police officers from Unite the Kingdom protesters.
Earlier, huge crowds massed near Waterloo Station with people wearing and waving union flags and the St George cross
He also claimed UK courts had decided the rights of undocumented migrants superseded those of the "local community".
Last month, the Court of Appeal overturned an injunction blocking asylum seekers being housed at The Bell Hotel in Epping, Essex.
TV presenter Katie Hopkins also spoke after earlier appearing alongside Robinson, Lawrence Fox and Ant Middleton at the front of the march.
Musk made a surprise appearance via videolink, calling for a "change of government".
"You can't - we don't have another four years, or whenever the next election is, it's too long," Musk told the crowd. "Something's got to be done. There's got to be a dissolution of Parliament and a new vote held."
EPA
"We know racism and violence and fascism is not new," she said. "But you know what? We have always defeated that racism and violence."
Ahead of the march, the Met confirmed it would not be using live facial recognition - which captures people's faces in real-time CCTV cameras - in its policing of the Unite the Kingdom march.
It also said there were "particular concerns" among some in London's Muslim communities ahead of Robinson's protest, citing a "record of anti-Muslim rhetoric and incidents of offensive chanting by a minority at previous marches".
EPA / Counter protesters were also set to march through central London, ending up near Robinson's demonstration
She said: "Officers will take a firm line on behaviour that is discriminatory or that crosses the line from protest into hate crime."
She added that police would act "without fear or favour" and asked demonstrators to "be considerate of the communities they are passing through".
The Met said that it had ordered the Unite the Kingdom rally to end by 18:00 and the counter-protest to end by 16:00, in line with when the organisers told the force they expected speeches to end.
Robinson was released from prison earlier this year after being jailed in October for ignoring an order not to repeat false claims about a Syrian refugee, who had successfully sued him for libel.
