Who are the hate preachers radicalising rightwing extremists? As the head of MI5 warns that anti-migrant haters are increasingly considering terrorist attacks, it is surely a question we must ask. After all, the role of hate preachers in Islamist terrorism has long been debated.

After the London Bridge Islamist terrorist attack in 2017, Nigel Farage demanded that Sadiq Khan – “as the first Muslim mayor of London” – declare that he would do all he could “to work with the Muslim community to drive out the extremist preachers from our mosques” and to fight radicalisation in schools and prisons. More recently, he suggested that Muslim parents in the United Arab Emirates feared sending their children to study in British universities “given the risk of radicalisation here”. His colleague Suella Braverman agrees. “There should be zero tolerance for hate preachers in mosques or radicalising imams in prisons,” she says.

And what of Robert Jenrick, Reform UK’s self-styled shadow chancellor, who warns of “terrorist influencers and radicalising inmates” in prisons and demands “complete zero tolerance on hate preachers”?

Yet on the very day of MI5’s warning, Jenrick declared that Royal Marines would be deployed to turn back migrants in the Channel – and that “if they need to use lethal force, then they’ll be able to do so”. Here was one of Britain’s most prominent politicians injecting violence into our already deeply toxic debate about immigration.

Farage sought to backtrack on Jenrick’s behalf, claiming force “would be used only if soldiers were fired at” and insisting that Jenrick had been “utterly misconstrued”. This made little sense: the Home Office said last year that it had no record of firearms being brought in via small boats over the previous seven years.

Not that long ago, there was supposed to be a strict demarcation between the mainstream right and extremists. No longer. Consider the ITV investigation, screened last night, that exposed Reform councillors describing Asian families as “parasites” and Black children as “animals”. Another spoke of training young men to round up migrants “street by street, house by house”. One spoke of holding asylum seekers in “concentration camps”. Another Reform figure spoke of criminals facing “Sunday morning rose garden executions”. Some of these individuals have since stood down. But while the leaders of Reform have not yet plunged to such extreme depths, what effect might their own words have on impressionable people?

Consider that last week, Jenrick appeared on the YouTube channel of former GB News presenter Dan Wootton, a supporter of both Tommy Robinson and the anti-migrant activist Daniel Thomas, the latter of whom he calls “a British hero”.

Take the anti-migrant protests outside hotels housing asylum seekers. Last August, Jenrick turned up to such a demonstration in Epping, Essex, where far-right activists were also present, praising the “peaceful, patriotic protesters”. A month earlier, following clashes which left eight police officers injured, Braverman insisted the protests had been “largely … peaceful”. Farage, meanwhile, warned that Britain was close to “civil disobedience on a vast scale” and said he understood the anger in Epping: “You bet your life I do.”

Asked about Thomas’s group, Patriot Platform, Jenrick sympathised with masked protesters, arguing that, without a face covering, “you can lose your job, you can be cancelled”. When he was pushed on whether he would accept Robinson supporters into Reform, Jenrick’s response was telling. “Ultimately [it’s] not my call who comes into the party, that’s for Nigel and others in the party to determine,” he said. “But look, I want to build as broad a coalition as possible of people who share my values, who want us to fix this country.” How to square this with Jenrick’s denunciation of Islamist hate preachers?

In the recent past, Reform politicians – Farage, Jenrick and Braverman among them – have described migrants arriving in small boats as an “invasion”. It is the language of war: a nation under siege, an enemy to be repelled. It is hardly a leap for fearful people to conclude that those who resort to violence are not really dangerous extremists, but patriots defending their country.

We can hardly forget that Farage called for “pure, cold rage” in response to alleged police failings over the murder of Henry Nowak. Hours later, violence erupted on the streets of Southampton. He increasingly embraces the language of white resentment, claiming that “anti-whiteness is institutionalised into every aspect of public life”, calling diversity policies a form of “social cleansing” and warning of white Britons becoming a minority by the end of the century. Such rhetoric echoes the “great replacement” conspiracy theory, which argues that white people are being deliberately displaced by mass immigration.

Reform’s home affairs spokesperson, Zia Yusuf, meanwhile, describes Conservative and Labour politicians as “traitors to their country”, warning – without elaboration – that a “reckoning is coming”.

None of these statements constitute a direct incitement to violence. But taken together, they can conjure up a terrifying picture in impressionable minds: a nation and a people under attack, its own political leaders conspiring in its destruction and time running out to save it.

This can’t be divorced from rightwing media outlets echoing and amplifying such rhetoric. We’ve already had the far-right uprising of August 2024, when racist mobs assaulted people of colour in the streets, attacked mosques and migrant-owned businesses, and tried to burn down hotels housing asylum seekers. We’ve had far-right terrorist attacks, such as the neo-Nazi attempted murder of an Eritrean man in 2024, the firebombing of an immigration centre in Dover in 2022, the attack on the Finsbury Park mosque in 2017 and the murder of Jo Cox a year earlier.

None made a dent on the national discourse. It has only become cruder, more toxic and more inflammatory. So, with all we know, time to ask again. Who are the hate preachers radicalising rightwing extremists?

• Owen Jones is a Guardian columnist. His latest book, The Fall of the West, is out now. To support the Guardian, order your copy at guardianbookshop.com. Delivery charges may apply.