Far-right extremists have been using British-registered social media platforms to circulate antisemitic and neo-Nazi material - sparking fears that vulnerable individuals may have been radicalised during the Covid-19 lockdown, a new report has shown.

The report from the Community Security Trust (CST) highlighted a widely circulated graphic that listed a number of British-Jewish organisations and locations of synagogues, as well as four social media platforms that have been most used to spread such material.

The graphic blamed Jews for “forcing multiculturalism upon Europe” and “forcing these invaders into your country”.

The new CST report - entitled Hate Fuel: the hidden online world fuelling far right terror - coincides with a massive surge in neo-Nazi propaganda being shared on social media in the wake of the killing of George Floyd in America.

It stresses that the problem of far-right indoctrination is not limited to platforms such as Facebook and You Tube, and alternative platforms such as Bitchute, Telegram, Gab and 4chan are now being targeted by extremists to promote a race war.

Bitchute, a UK registered company, is revealed to have hosted propaganda videos from the proscribed National Action group along with thousands of other antisemitic videos, which have been viewed thousands of times.

Gab host to a dedicated network of British users called “Britfam” that has 4,000 members and approximately 1,000 posts per day. Far-right extremists use the network to circulate racism, antisemitism and Holocaust denial.

Telegram has also hosted several images and posts celebrating British terrorists Thomas Mair and David Copeland, and other far-right terrorists such as Brenton Tarrant and Robert Bowers; as well as images calling on users to kill Jews.

CST has shared the report in recent weeks with Counter-Terror Police, the Home Office, the Counter-Extremism Commissioner and Lord John Mann.

Some of the National Action’s videos were taken down from Bitchute after the CST’s report highlighted they were online.

While the main body of the report was completed on May 1, the report includes an appendix showing that these same platforms all host racist content on the killing of George Floyd and the protests in the United States.

This includes recent material celebrating or justifying Mr Floyd’s death; content calling for more killings; messages welcoming the idea of a race war; and antisemitic content claiming that Jews are behind the protests.

Speaking to Channel 4 News on Thursday after they revealed details of the CST report, Neil Basu, head of Counter Terrorism Policing, voiced concerns about online radicalisation amid the lockdown.

He said: “My professional instinct is to tell me that throughout all of Covid, one of my biggest fear is people have been locked down looking at nothing but their screens for over three months now, and there has been an increase in propaganda grievance narratives being twisted online to try and radicalise people who are vulnerable and people have never been more vulnerable.”

Mark Gardner, the CST’s Director of Communications, said: “We now need to move on to the incitement part – how is this ideology being spread?”

He added that counter-terrorism police need to take this kind of far-right online activity “as seriously as they did when Al Qaeda and Isis were putting this kind of material out.”

New online laws are to be introduced designed to hold social media companies hosting this material to account.