For the last year, I have been deep undercover inside the far right, both in the UK and USA, working on behalf of anti-racism organisation HOPE not hate.

I spent twelve months rubbing shoulders with some of the most prominent antisemites active in the UK today, including infamous Holocaust deniers like David Irving, Lady Michèle Renouf and Vincent Reynouard.

Once I infiltrated the network by telling people I was a disgruntled student fed up with my native Sweden’s liberal laws, I found a world of extreme antisemitism where the Holocaust was a joke, something to be laughed at and denied.

In fact, I found a paranoid belief in a global Jewish conspiracy provided the framework for most things considered “wrong”. Whether it was the LGBT community, progress in women’s rights or mass immigration, the cause was always said to be “the Jews”.

In late March this year, I met David Irving in a café by Sloane Square. Through much practice he had perfected all his answers to my questions in order not to appear like a denier, resolutely stating that the Holocaust “absolutely did happen”.

But as our conversation went on, he relativised it to the point where the genocide was comparable to the actions of the Allies and the number of murdered was halved. He concluded by saying that he was “pretty certain that at Auschwitz, not much happened”.

At the London Forum, the UK’s leading fascist “think tank”, I discovered that Holocaust denial was commonplace. In fact, the very idea of the Holocaust was treated as a hilarious joke, while the most extreme among the group openly proposed that it might need to happen again.

It’s not a coincidence that one of the first questions I was asked by Stead Steadman, one of the forum’s organisers, was my position on the JQ – the “Jewish question”.

Despite being divided on certain issues, all of the most extreme far-right groups are deeply antisemitic. Even expressed in its least violent form, the so-called Jewish question was used to justify arguments for the mass deportation of Jews.

Antisemitism has become the underlying explanation for most things those in the far right consider wrong in the world. Although these groups spread hate widely, particularly against Muslims, LGBT people and women, antisemitism often seeps through it all.

In May, I attended a secret London Forum meeting at a Marylebone hotel where I met Greg Johnson, the leading American “alt-right” figure. He told me over coffee that Jews everywhere needed to be expelled to Israel.

“We need to freeze them out. You’re not going to be professors; you’re not going to be influential,” he said. “We are going to squeeze you out”.

In recent years, attacking Geroge Soros has become a code word for traditional Jewish conspiracy theories. Tomislav Sunić, a leading European far-right author from Croatia, said at a recent London Forum conference that “we can blame George Soros for being the mastermind of those tsunamis” – referring to refugees coming to Europe.

Jez Turner, the head of the London Forum, argues that it’s the “Zionists who promote homosexual degeneracy” in order to undermine the reproduction of the white race.

In America, I met a leading member of the AltRight Corporation, New Jersey academic Jason Jorjani, who laid out a future of expulsions, concentration camps and war in Europe and foresaw a future in which Adolf Hitler was regarded as a "great European leader” whose face would be on bank notes by 2050.

These beliefs are the fuel on which this movement runs because the progress of emancipatory movements in LGBT rights, feminism and anti-racism are difficult for the far right to explain. If the white heterosexual man is supposed to be superior to all others, how come the Mayor of London is not white? Why have some minority struggles made progress over the last century, despite those minorities being inferior? How is it that women run large companies?

Some invisible force must be helping these groups, the far-right argument goes, because these supposedly inferior people cannot have the capacity to make their own progress. The conspiracy of a Jewish cabal, global in reach and with infinite resources, provides the much-needed explanation that keeps these inconsistencies from undermining fascist ideology. It excuses their failures and provides an umbrella for all other forms of hate.

Patrik Hermansson is a researcher for HOPE not hate. The full story of his year undercover will be featured in a forthcoming film, My Year In Kekistan.