On Wednesday morning Donald Trump retweeted three videos posted by a British extremist named Jayda Fransen recently convicted of hate crimes. Two of the videos purported to show Muslims committing violent acts, but have been debunked as inaccurate or misleading.

The third video, depicting a bearded man destroying a statue of the Virgin Mary, is ironically very much akin to the sort of religious desecration associated with the oft-arrested Fransen’s hate group, Britain First—except when Fransen does it, it’s in the faces of British Muslims.

Even among British fringe figures, Britain First is considered radioactive, and for good reason: When a man named Thomas Mair murdered British MP and 41-year-old mother of two Jo Cox in June 2016, he repeatedly shouted “Britain First!” Trump’s retweets will almost certainly help revitalize the struggling group, according to experts.

Cox’s husband Brendan Cox responded to Trump on Twitter on Wednesday:

Trump has legitimised the far right in his own country, now he’s trying to do it in ours. Spreading hatred has consequences & the President should be ashamed of himself. — Brendan Cox (@MrBrendanCox) November 29, 2017

Nick Ryan, who works for UK-based antiracist group Hope Not Hate, told TPM that Britain First is committed to violence in a way that distinguishes it even from other far-right outfits. Publicly a “Christian” organization, Ryan said, Britain First uses crucifixes and Bibles in pranks intended to provoke angry responses from Muslims, which are videotaped, often misleadingly edited, and posted on social media in a bid for the sort of attention and publicity that the President of the United States provided Wednesday morning.

“[Britain First] originated from a very far-right party in the UK, the British National Party,” Ryan explained. The group is nominally involved in electoral politics, he said, but it is more interested in public stunts that can make Muslims look bad or bring them physical harm. Its membership—and it is a small organization of about 1,000 people across the entire U.K.—is composed of “thugs who are committed to violence.”

“These aren’t guys in bow ties discussing eugenics, as disgusting as that may be,” said Ryan. “They’re coming from a street-based understanding of politics.”

Fransen made British headlines for marching through a predominately Muslim area of Luton in a paramilitary uniform carrying a large crucifix and picking fights with the locals; she was arrested, prosecuted, and fined under a statute that forbids the wearing of uniforms “for a political purpose;” the law was passed in the 1930s in an effort to control British fascists like Oswald Moseley’s notoriously violent brownshirts, though it has also been used to prosecute political protestors.

When it comes to Britain First, there is little ambiguity about the group’s taste for violent confrontation. “When someone insults them back, they videotape it and then share it very rapidly on their social platforms to promote the idea that there are no-go areas and they’re just Christians minding their own business, when in fact they’re trying to incite violence,” said Ryan. “They’ll go into mosques in paramilitary uniforms and walk over the prayer mats with big heavy boots, thrust a Bible into the hands of the imams and tell them they’re worshipping a false prophet. I’ve seen them go into Brick Lane in a disused military vehicle handing out leaflets; it’s all these very high-profile stunts designed to get attention.”

Even far-right figures were horrified by Trump’s tweets on Wednesday morning; dissembling conspiracist Paul Joseph Watson tweeted that “someone might want to tell whoever is running Trump’s Twitter account this morning that retweeting Britain First is not great optics.” Britain’s own prime minister Theresa May, formerly one of the president’s staunch allies, condemned Trump, apparently for the first time: “It is wrong for the president to have done this,” she said.

Trump’s tweets can often be lined up with whatever is on cable news at the moment; in this case it’s less clear how he came across Fransen’s twitter feed. However it happened, his actions Wednesday morning will doubtless reinvigorate a movement the vast majority of the U.K. deplores and hopes will go away. “Trump’s retweets are just throwing oil on a dying fire,” Ryan said.

“I don’t see how it advances America’s interests.”

This post has been updated.