A toxic mix of antisemitism, Islamophobia and sexism is revealed at the heart of the “alt-right” movement, following an investigation by an openly-gay anti-fascist activist that sheds new light on the far-right’s rising influence over political parties on both sides of the Atlantic.

Members of the group were caught discussing “gassing Jews” and killing their left-wing opponents after Hope Not Hate conducted a major study of white supremacists in the US and Europe.

The exposé reveals how the “alt-right” is breathing new life into once dormant far-right and racist groups around the world, uniting them under one international movement.

It uncovers the infiltration of the “alt-right” in the UK, with Sheffield-born blogger Paul Joseph Watson among those using their online following to reach audiences the traditional far-right has until now been unable to muster.

As a general principle The Independent avoids using the term “alt-right”, on the basis it is a euphemism employed to disguise racist aims.

The report says a second, “moderate” wing – dubbed the “alt-light” – has become increasingly influential on right-wing politics in Britain, pushing Ukip and others into ever-more hard-line territory.

Authors of the study The International Alternative Right: From Charlottesville to the White House also claim to have found links between the hard-right network and the Trump administration.

Speaking of his experiences infiltrating the network of white supremacists, Patrik Hermansson said: “For almost a year I’ve been at the heart of a world of extreme racism, antisemitism, Holocaust denial, esoteric Nazi rituals and wild conspiracy theories.

“What I found was a movement that sometimes glorifies Nazi Germany, openly supports genocidal ideas and is unrelentingly racist, sexist and homophobic.”

Mr Hermansson said he first gained access to the movement after joining the far-right “think tank” London Forum, having claimed to have come to the UK as a disillusioned Swede curious about the “alt-right” and inspired by Brexit.

He was then introduced to other groups, including the Extremists Club and the Traditional Britain Group, which aims to “preserve the ancient traditions, peoples and beliefs” of the UK.

He said: “In this world, Holocaust denial and conspiracy theories are commonplace, so much so that a whole group exists to cater specifically for them.

“I spent endless mind-numbing hours at meetings of the [conspiracy theorist group] Keep Talking, listening to speakers deny climate change, debate whether 9/11 was a false flag attack or if an ill-defined ‘they’ sold birth certificates on the stock market. Trestle tables at the edge of the hall were adorned with Holocaust denial books.”

The label “alt-right” was first adopted by white supremacist Richard Spencer, but was brought to mainstream attention by individuals with a larger social media presence such as Milo Yiannopoulos and Mike Cernovich.

The movement has evolved rapidly since its inception in 2010, appropriating internet memes such as Pepe the Frog and images of milk as a symbol of white supremacy.

Techniques used to promote their far-right ideology include the “OK” hand gesture to mean white power and the “peace” sign gesture as a denial of non-binary gender identity.

Other references, including to the fictional nation of “Kekistan”, whose green, white and black banner deliberately mimics a German Nazi war flag, have been adopted as part of a strategy to troll their opponents and publicise their cause.

Report co-author, Dr Joe Mulhall of Hope Not Hate, said: “Despite its roots stretching back decades, the Alternative Right remains much misunderstood.

“This movement seeks to destroy the liberal progressive consensus and the movements and rights that derive from it.

“Some of the platforms pushing this agenda have the ability to reach hundreds of thousands or even millions of people every month.”

“Its danger can also be seen in the murder of Heather D Heyer in Charlottesville, Virginia, in coordinated anti-semitic harassment campaigns, and in the electoral impact of the conspiratorial #HillaryHealth fabrication or the #MacronLeaks scandal, which were promoted by alt-light activists.”

Hope Not Hate, a UK-based anti-racist charity founded in 2004, is now setting up in the US, where it says one of the leading “alt-right” figures, Jason Jorjani, a founding member of AltRight Corporation, has links with the Trump Administration stretching from the 2016 campaign to the presidency.

But its latest report suggests the phenomenon of far-right extremism under the “alt-right” banner has become well established on this side of the Atlantic.

The study says the “alt-right” has re-energised formerly declining parts of the European extreme right.

People, organisations, websites and publishers that have traditionally classed themselves as part of the European New Right have begun to rebrand themselves as “alt-right” and adopted the iconography of the movement.

The report states: “Importantly, on both sides of the Atlantic the Alternative Right has managed to galvanise a whole new generation of far-right activists.