The far-right activist Tommy Robinson told tens of thousands of supporters to prepare for the “battle of Britain” during a rally in London on Saturday.

Robinson, whose real name is Stephen Yaxley-Lennon, drew tens of thousands of supporters on to the streets of central London for the second year running in an event where Islamophobic and ethnonationalist hate speech and flyers were distributed to the crowds.

Organisers claimed that millions had attended his “unite the kingdom” march, but police estimated the number of demonstrators to be far lower, at about 60,000. Last September’s march was attended by 150,000 people.

Robinson, who gained prominence as the founder of the anti-Islam English Defence League, told crowds gathered in Parliament Square that the rally was “a turning point for Britain”.

He encouraged his supporters to move beyond street protest and “fighting” and become involved in local politics before the next general election.

The campaign group Hope Not Hate said that although the march appeared to have attracted fewer demonstrators than the previous rally, the scale of Robinson’s movement remained “deeply worrying”.

It added: “Today’s numbers still dwarf anything ever managed by the English Defence League and hundreds of thousands more watched the livestream online. While it looks like the movement’s growth may have stalled, it still remains a significant threat.”

The Metropolitan police said it had spent £4.5m policing the march and a separate pro-Palestinian demonstration which ended in Waterloo. There were about 4,000 officers on duty. Armoured vehicles, dogs, drones and helicopters were also deployed throughout the afternoon.

The force said that, as of 7.30pm, it had made 43 arrests across both events. It said it would “provide a more detailed breakdown” when the marches had concluded.

A spokesperson added: “While this may seem high, to this point both protests have proceeded largely without significant incident.”

Two men were arrested near Euston station after arriving in London to attend the Unite the Kingdom rally. One was wanted on suspicion of grievous bodily harm after an incident in Birmingham where a man was run over. The second was arrested in connection with a separate offence, which involved encouraging people to attack a police officer.

The protests had a significant Christian theme with many protesters who marched to Parliament Square carrying wooden crosses and chanting “Christ is king” as they waited for the march to begin. Others wore red “make England great again” hats.

Addressing the crowd, Robinson said: “Are you ready for the battle of Britain? 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 for ever.

“We have to get political, we have to get involved. I’m not going to tell you which political party you need to join. We’re a cultural movement. I’m going to tell you that you have to join a political party. I don’t care if it’s Reform, if it’s Advance, or it’s Restore, or it’s the Conservative party. We have to locally get involved in politics.”

Robinson also led chants of support for the X owner, Elon Musk, one of his best-known supporters. He said: “None of this would have happened if it wasn’t for one man. Thank you Elon on behalf of Great Britain.”

The rally was also addressed by Siobhan Whyte, whose daughter Rhiannon was murdered by the Sudanese asylum seeker Deng Majek during an attack at the hotel where she worked in Walsall, West Midlands, in 2024. Majek was jailed for life in January.

Whyte 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.”

The Polish politician Dominik Tarczyński, who claimed to have been banned from entering the UK by Starmer before the rally, addressed the crowds via video link. He said: “He could ban me. He will not cancel you. And believe me, there will be a day I will be back.”

The government is understood to have blocked 11 foreign nationals – described by Starmer as “far-right agitators” – from entering the UK before the rally.

Katie Hopkins, the former Apprentice contestant turned far-right commentator, also sent a video message to the demonstrators. She said: “I want to thank you all for being at the ‘unite the kingdom’ rally today. Whether you’re here in London or joining us from overseas, welcome to Great Britain.

“I want to say a few things to you, if I may. I see you, and I see our capital city, and it looks for the first time in a very long time like the place that I remember, and our capital city and a place that we can all call home, and I’m so proud of you.”

Some demonstrators distributed flyers saying they wanted to secure “a future for white people”. The leaflet said: “In a country saturated with degenerates, grifters and imported political enemies … We are a brotherhood of White Europeans who share the same values.” It added that anyone could join their “vanguard” and they could remain anonymous.

Writing on X on Saturday, the justice secretary, David Lammy, said: “The Unite the Kingdom march organisers are spreading hatred and division. They do not reflect the Britain I’m proud of.

“Peaceful protest is a fundamental right and one I will always protect. But if protest turns violent, we will act swiftly, with extra court capacity in place.”

The campaign group Led by Donkeys said it put up a giant screen at the rally which played a video with the slogan: “Immigration makes Britain brilliant.”