Far-right protests are attracting the largest number of supporters since the 1930s as Brexit fuels anger against the “elite”, a report has warned.

Research for the Commission for Countering Extremism, seen exclusively by The Independent, said tens of thousands of people have descended on London since the start of 2018 over Tommy Robinson’s imprisonment and delays to Britain’s departure from the EU.

Some “Free Tommy” protests spilled over into violent attacks on police officers, while “Brexit betrayal” marches saw demonstrators carry nooses and drag effigies of politicians through the streets.

A report by Dr Joe Mulhall, a senior researcher at Hope Not Hate, warned that “the inability of politicians to manage Brexit competently and decisively” was undermining faith in the political system.

“When people feel that the system is broken, they look outside of it and step into a political arena where the far right is able to capitalise on these fears, offering simplistic answers to complex problems,” the report said.

"Brexit betrayal" march in London Show all 43 1 /43 "Brexit betrayal" march in London "Brexit betrayal" march in London A protester holds an anti-BBC sign Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator holds a sign in the picket line Angela Christofilou/The Independent "Brexit betrayal" march in London A protester carrying a noose at the "Brexit betrayal" march. The man carrying it told a reporter: "That's what the traitor May deserves." AP "Brexit betrayal" march in London Pro-brexit supporters hold a sign opposed to Nigel Farage Angela Christofilou/The Independent "Brexit betrayal" march in London Protesters carry a defaced British flag on the march Angela Christofilou/The Independent "Brexit betrayal" march in London Tommy Robinson addresses a rally after taking part in a Brexit 'betrayal' march in central London PA "Brexit betrayal" march in London Police officers attempts to keep rival protesters from clashing at the Brexit 'betrayal' march in London Victoria Jones/PA "Brexit betrayal" march in London A protester holds an anti-Theresa May sign Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator and his dog Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator at the protest Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit sign at the rally Angela Christofilou/The Independent "Brexit betrayal" march in London Pro-brexit demonstrators endorse UKIP Angela Christofilou/The Independent "Brexit betrayal" march in London A Brexit 'betrayal' march protester wearing a Make Britain Great Again hat in London on 9 December 2018 Chris J Ratcliffe/Getty "Brexit betrayal" march in London Brexit 'betrayal' marchers gathering on Park Lane ahead of a protest Angela Christofilou/ The Independent "Brexit betrayal" march in London The "Brexit Betrayal" march passes through Central London Angela Christofilou/The Independent "Brexit betrayal" march in London Tommy Robinson tells protesters to join Ukip via their mobile phones on stage next to leader Gerard Batten (right) at the Brexit 'betrayal' march Gareth Fuller/PA "Brexit betrayal" march in London A protester speaks thorugh a megaphone on the march Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator walks in the picket line Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit anti-May sign at the rally Angela Christofilou/The Independent "Brexit betrayal" march in London A protester carries a Union Jack on the march Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator wrapped in the Union Jack Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit anti-May sign at the rally Angela Christofilou/The Independent "Brexit betrayal" march in London Pro brexit demonstrators move through Central London Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator marches with sign Angela Christofilou/The Independent "Brexit betrayal" march in London A pro-brexit demonstrator holds a rude sign in the rally Angela Christofilou/The Independent "Brexit betrayal" march in London The march passes down Victoria Street near Parliament Angela Christofilou/The Independent "Brexit betrayal" march in London A festive protester marches near Parliament Angela Christofilou/The Independent "Brexit betrayal" march in London A protester holds a mock noose as the march passes down Victoria Street towards Parliament Angela Christofilou/The Independent "Brexit betrayal" march in London A protester wrapped in the Union Jack marches down Victoria Street towards Parliament Angela Christofilou/The Independent "Brexit betrayal" march in London A protester makes some noise on the march Angela Christofilou/The Independent "Brexit betrayal" march in London A protester dressed as a dinosaur holds a sign rallying against "Davocracy" - in reference to the annual World Economic Forum meeting in Davos Angela Christofilou/The Independent "Brexit betrayal" march in London A protester holds a pro-brexit sign on the march Angela Christofilou/The Independent "Brexit betrayal" march in London The march approaches parliament Angela Christofilou/The Independent "Brexit betrayal" march in London A protester distributes pro-brexit lapel badges Angela Christofilou/The Independent "Brexit betrayal" march in London A demonstrator wears an anti-EU poster and holds an anti-BBC sign Angela Christofilou/The Independent "Brexit betrayal" march in London A smoke bomb is deployed in Parliament Square as the march comes across the counter-demonstration Angela Christofilou/The Independent "Brexit betrayal" march in London Angela Christofilou/The Independent "Brexit betrayal" march in London A flag bearing the Arms of Plantagenet flies in theprot Angela Christofilou/The Independent "Brexit betrayal" march in London Protesters on the Brexit 'betrayal' march in London on 9 December 2018 Angela Christofilou/ The Independent "Brexit betrayal" march in London Protesters on the Brexit 'betrayal' march in London on 9 December 2018 Angela Christofilou/ The Independent "Brexit betrayal" march in London Brexit 'betrayal' marchers gathering on Park Lane ahead of a protest on 9 December 2018 Angela Christofilou/ The Independent "Brexit betrayal" march in London Brexit 'betrayal' marchers gathering on Park Lane ahead of a protest on 9 December 2018 Angela Christofilou/ The Independent "Brexit betrayal" march in London Angela Christofilou/The Independent

Dr Mulhall warned that whatever the outcome of Brexit, the far-right will “use the narrative of betrayal to advance their politics for the next 10 years”.

He told The Independent: “If there is a hard Brexit and these communities get hit, they will come up with an excuse and say something went wrong, we didn’t leave strongly enough.

“If we stay in, it’s been betrayed. The far-right will be using this, regardless of what happens.”

Robinson, whose real name is Stephen Yaxley-Lennon, is among the high-profile extremists capitalising on anger over the delay to Brexit.

After being appointed as a senior adviser to Ukip’s former leader Gerard Batten last year, he said he was “jumping on the Brexit bandwagon” and then ran as an independent MEP.

“The people I know who voted didn’t think about the economy, they thought more about their culture and their identity,” Robinson told crowds at the Ukip-organised Brexit Betrayal March in December.

“Let this be the start of a political mass movement in this country to represent every single one of you who feels voiceless.”

One supporter in the crowd was carrying a hanging scaffold and noose, while other protesters waved placards accusing politicians of “treason” and chanted abuse at the media.

Robinson’s first imprisonment for contempt of court in May 2018 had already triggered demonstrations that drew tens of thousands of his supporters to the streets, and a fresh protest against his second sentence is scheduled for 3 August.

Tommy Robinson supporters descend on Parliament after EDL founder jailed for nine months for contempt of court

Dr Mulhall said the event could see a significant turnout, despite Robinson’s reach being damaged by his imprisonment and a series of social media bans, as organisers mobilise anger against the “establishment”.

“There’s little doubt that no matter which side of the Brexit debate you fall on, the failure to deal with it competently has fed into disillusionment and anger,” he added.

“We’ve seen through polling that people are increasingly disillusioned with all political parties and leaders, but they are still angry and want change. So they’re looking for alternatives, and for some of them that is Tommy Robinson.”

YouGov polling released earlier this month suggested that 56 per cent of Conservative Party members believe Islam was “generally a threat” to the British way of life, while two thirds believed in the myth of no-go zones where “non-Muslims are not able to enter”.

Dr Mulhall said the research suggested that large portions of the British public agree with views espoused by anti-Muslim figures like Robinson, and any politician that repeats them “without the far-right baggage” may enjoy election success – “whether that’s Boris Johnson talking about women as letterboxes or someone who hasn’t popped on the scene yet”.

He cautioned that concerns exploited by the far right, over employment, immigration, grooming gangs and terrorism, must be addressed by the government to avoid economically disadvantaged parts of Britain becoming a “wellspring for far-right activism”.

The research found that Britain’s biggest right-wing extremist groups had modernised themselves by moving away from explicit antisemitism, through anti-immigration rhetoric and broad racism, to focus specifically on Muslims.

“The far right has adapted its message and adopted a platform that is more palatable to the public, within the confines of acceptability,” it said, detailing how groups were repurposing the notion of free speech to present themselves as human rights activists and freedom fighters.

“Those who publicly limit their racism to Muslims, bemoan the supposed suppression of their rights and freedoms and claim to represent the oppressed “people” versus a corrupt “elite” echo the views of much larger sections of the British public and thus have found success in attracting larger numbers than at any time since the 1930s.”

Protesters at the December 2018 ‘Brexit betrayal’ march led by Ukip and Tommy Robinson (Angela Christofilou/The Independent)

The research was one of four papers on the far-right, commissioned by the new Commission for Countering Extremism, which was set up by the government in 2017 and has been conducting nationwide research on people’s views and experiences of extremism ever since.

Sara Khan, the lead commissioner, said the findings “paint a picture of the breadth and severity of the far-right, and the need for proportionate, open-minded responses”.

“We have to guard our right to protest and offend but I believe we can and must do more,” she added.

“These ideas and threats never went away, and we must redouble our efforts to counter them.

“We want this research, and the other papers we release over the summer, to build an evidence-led consensus on the problems we face from extremism, and find even better ways of countering it.”

Sajid Javid was to set out his response to the findings at a speech in central London on Friday morning.

“Anyone can challenge the myths peddled by extremists that deepen divisions,” the home secretary was to say.