More than 100,000 people have joined a march in central London organized by far-right activist Tommy Robinson, with a counter-protest by anti-racism campaigners also taking place.

The "Unite the Kingdom" rally gathered at Waterloo before heading to Whitehall where they heard speeches, including from tech billionaire Elon Musk.

While the first half of the day was largely peaceful, the Metropolitan Police later said officers had faced "unacceptable violence", with projectiles thrown at them. Nine people have been arrested.

Meanwhile, about 5,000 people joined the nearby counter-protest organized by Stand Up To Racism (SUTR).

Home Secretary Shabana Mahmood condemned "those who have attacked and injured police officers".

"Anyone taking part in criminal activity will face the full force of the law," she said.

Some 1,000 Met officers were deployed ahead of the protest and were bolstered by an extra 500 officers from other police forces including Leicestershire, Nottinghamshire and Devon and Cornwall.

Around mid-afternoon, the two demonstrations were divided on Whitehall by a line of police officers.

While the majority of the group protested peacefully, the Met said some officers had been attacked while trying to keep the two 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."

Into the evening extra riot police could be seen rushing through the crowd to back up the horses and officers holding lines between the two groups.

Projectiles were thrown at officers from Unite the Kingdom protesters who had gathered near Trafalgar Square.

"When officers moved in to stop them they faced unacceptable violence," the Met said in a statement.

"They were assaulted with kicks and punches. Bottles, flares and other projectiles were thrown."

At one point, a glass bottle appeared to smash against a horse, causing the animal and rider to stagger backwards.

Scuffles broke out as police used batons to try and push back Robinson supporters gathered on the top of Whitehall and Trafalgar Square.

Robinson, whose real name is Stephen Yaxley-Lennon, addressed the crowds at the "freedom of speech festival" where he criticised politicians for "parroting" his ideas.

He also claimed UK courts had decided the rights of undocumented migrants superseded those of the "local community".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.

Making a surprise appearance via videolink, Musk spoke about "massive uncontrolled migration" and called for a "change of government" in the UK.

"Something's got to be done," Musk said as he was interviewed by Robinson.

"There's got to be a dissolution of Parliament and a new vote held."

TV presenter Katie Hopkins also spoke on stage after earlier appearing alongside Robinson, Lawrence Fox and Ant Middleton at the front of the march at the start near Waterloo station.

At the Stand Up To Racism rally, independent MP Diane Abbott told demonstrators: "We know racism and violence and fascism is not new.

"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".

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 organizers 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. (BBC)

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