A total of 43 arrests had been made by around 7.30pm, with police saying that while the figure “may seem high, both protests have proceeded largely without significant incident”.

Four officers were assaulted during the day and six were subjected to hate crime offences, the Metropolitan Police said.

Around 4,000 police officers were deployed across both marches in what the Met described as one of its biggest policing operations in recent years, expected to cost £4.5million.

Huge crowds draped in St George’s Cross and Union flags marched from Kingsway along Whitehall to Parliament Square, chanting “Keir Starmer’s a w****r” and “we want Starmer out” as they walked.

Some demonstrators wore red “Make England Great Again” hats, carried wooden crosses and chanted “Christ is King” while others held banners reading “Jesus is the way of life”.

A small number waved flags of the pre-revolution Iranian monarchy, suggesting support for American and Israeli efforts to topple the Iranian regime.

An estimated 50,000 people joined the Unite the Kingdom rally

The nearby pro-Palestine march saw the flag of Iran’s Islamic Republic prominently displayed.

Mr Robinson, whose real name is Stephen Yaxley-Lennon, addressed the crowd in Parliament Square and urged supporters to channel their energy into political action ahead of the next general election.

He said: “Are you ready for the battle of Britain?

“In 2029, we have an election. We’re not asking anyone to go out and fight, but this is the most important moment in our generation.

“If we don’t send a message in our next election, if you don’t register to vote, if you don’t get involved, if you don’t become activists, we are going to lose our country forever.”

Earlier in the day, Mr Robinson posted a video on X from the march saying: “Keir Starmer, the country’s awake, your days are numbered.”

The number of protesters for the pro-Palestine march has been unclear – with police estimating 30,000 people, but the event’s organisers saying it was 250,000

Among the other speakers at the Unite the Kingdom rally was Siobhan Whyte, the mother of Rhiannon Whyte, who was murdered by a Sudanese asylum seeker in Walsall in October 2024.

She said: “Keir Starmer, where do I even begin to discuss this abhorrent excuse of a leader of our country? He has failed us.

“He has failed my daughter, Rhiannon. I believe she would still be alive today if this disgusting excuse of a man had not been in control.”

Other speakers included Katie Hopkins, Ant Middleton, Laurence Fox and former Conservative MP Andrew Bridgen.

Unite the Kingdom protesters lit flares in Whitehall next to the Churchill statue

Polish politician Dominik Tarczynski, who claimed to have been banned from entering the UK by Sir Keir, appeared via video link.

Two men who arrived in London to attend the Unite the Kingdom rally were arrested near Euston station, with the Met confirming one was wanted in connection with a hit-and-run in Birmingham and the second for encouraging people to attack a police officer.

At the pro-Palestine march, which was commemorating the 78th Nakba Day, crowds carrying banners reading “Bristol stands with Palestine”, “Stop Trump, Stop Farage” and “Free Palestinian Hostages” gathered in large numbers, with many wearing keffiyehs.

Labour MP Diane Abbott told the rally that demonstrators faced a “common enemy” in the far-right, saying: “They are viciously right-wing, viciously racist, they are anti-black, anti-Muslim, and viciously antisemitic.

Former Labour leader Jeremy Corbyn told the Nakba Day supporters that Westminster needed a change in ‘policy’ not ‘personalities’

 | PA

“We have to come together to fight the racists, to fight the fascists, to fight the antisemites.”

Former Labour leader Jeremy Corbyn told supporters that Westminster needed a change in “policy” not “personalities”.

A woman was arrested after allegedly refusing to remove a fabric face covering at the pro-Palestine march.

Police also asked a separate group wearing orange jumpsuits and masks bearing the face of Reform UK leader Nigel Farage to remove their coverings.

The Crown Prosecution Service also issued new guidance ahead of the rallies urging prosecutors to consider whether placards, banners and chants shared on social media could amount to offences of stirring up hatred, reflecting what it described as “the changing international context”.

Sir Keir wrote on social media: “Today the voices of division will be loud. They don’t speak for the country I know, one that belongs to all of us. That’s our Britain. A Britain worth fighting for.”

Home Secretary Shabana Mahmood said ahead of the demonstrations the right to protest was “a cornerstone of our democracy” but warned “anyone spreading hate or committing acts of violence will face the full force of the law”.