There was outrage on Tuesday when Conservative MP Suella Braverman kicked off her address to a meeting in Westminster about Brexit by repeating a far-right, anti-Semitic conspiracy theory. "As Conservatives, we are engaged in a battle against Cultural Marxism," she reportedly said.

"Cultural Marxism" is a right-wing conspiracy theory with anti-Semitic origins, which looks at the mostly Jewish thinkers of the Frankfurt School of Philosophy. It draws on the racist trope of Jews as a "fifth column" who want to undermine traditional Western values.

When Guardian journalist Dawn Foster pointed out that Cultural Marxism was used by Anders Breivik, Braverman doubled down, saying, "Yes, I do believe we are in a battle against a Cultural Marxism, as I said."

So that's a sitting Tory MP happy to confirm that: yes, she does ascribe to a theory used as the justification for a racist terror attack. Surprising? Perhaps. But the use of the term will not have come as a shock to members of the Bruges Group, the Thatcher-admiring hard-right Brexiteer think-tank that organised the meeting.

Suella Braverman MP. Photo: Russell Moore / Alamy Stock Photo

Last year, VICE revealed that the group had been selling a booklet at their Conservative Party conference fringe event that made repeated references to Cultural Marxism. The book, "Moralitis, A Cultural Virus", by Bruges Group Director Robert Oulds and mental health lecturer Niall McCrae, also cited an article titled "The Great Replacement" – which is the name of the far-right conspiracy that was used by the mass-murderer in Christchurch to justify his horrific act this month. The article cited was published in The Salisbury Review, a conservative journal that was formerly edited by Roger Scrutton, a housing advisor for Theresa May who has described Islamophobia as a "propaganda word" and homosexuality as "not normal", and said there is "no such crime" as date rape.

Braverman's remarks might seem like strange subject matter for a meeting entitled "Brexit: No Ifs, No Buts", but it wouldn’t be the first time Euro-scepticism has mixed with conspiracy theory at a Bruges Group event.

At the Conservative Party Conference in 2016, Breitbart editor James Delingpole was introduced as "as a member of both UKIP and the Conservative Party", and applauded for his denial of climate change, before giving a wide-ranging speech in which he called the night of the referendum result his "special happy place" and mocked the BBC for caring about diversity. This has echoes of his claim in the Daily Mail that the BBC "fell for a Marxist plot to destroy civilisation from within", which was an example of the Cultural Marxism conspiracy theory entering the mainstream.

Believers in the conspiracy see political correctness as part of the Cultural Marxists' plot. At a Bruges Group event called "A Brighter Future" in 2006, one-time Tory election candidate John Midgley gave a speech called "A Britain without political correctness" in which he encouraged his audience to dream of a utopia where religious people "can set out their religious and moral case on the 'sinfulness of homosexuality' without being accused of a hate crime"; where "those who are a threat to our national security" are "deported immediately"; where "extremists who come to this country to try to undermine our traditions and our rule of law are told they are not welcome". In this paradise, "going to a fancy dress party dressed as a piece of coal for Halloween does not mean that you are being racially insensitive" – and yet, unfortunately, there would still be "those who try to preach a view of the world that is PC or culturally Marxist".

According to Midgley, "the EU is responsible for a huge chunk of our institutionalised political correctness". At the same meeting, speeches were heard by leading Brexiteers Nigel Farage, Conservative MEP Daniel Hannan and everyone’s least favourite Conservative MP, Philip Davies.

Moralitis co-author Dr Niall McCrae has used the Bruges Group website to repeatedly talk about Cultural Marxism, for instance in an article praising Tommy Robinson’s Day For Freedom – a far-right rally – as an "invigorating and necessary event", or defending Boris Johnson's infamous comments that people who wear the burqa look like "letterboxes".

McCrae has also warned that "a massive programme of propaganda and dirty dealings would ensue, funded by George Soros and the globalist elite" in the event of a second Brexit referendum. This draws on the conspiracy theory of Jewish liberal philanthropist George Soros as a "puppet master", a trope that bears a more than passing resemblance to classical anti-Semitism.

Following VICE's "Moralitis" revelations, Muslim and Jewish groups called on the Conservative Party to investigate. Did the Tories take those calls seriously? Did they buttons. The party said "we strongly condemn such offensive material", while claiming that it was nothing to do with them. The literature "was not distributed inside the Conservative party conference", a spokesperson said, despite the fact the event was listed in the party’s conference guide and was addressed by three Conservative MPs – two of them former cabinet ministers – and attended by a government whip.