I have been investigating antisemitism undercover for a few years now. Like most who see raw Jew-hatred at close quarters, I get tired of hearing those who believe this is all an argument to deflect legitimate criticism of Israel. So, I set out to show that hard-core antisemitism, completely unrelated to the conflict or Israeli policy, flourishes in pro-Palestinian circles.

Using a pro-Palestinian alias, I focused on the Palestine Solidarity Campaign, going from branch to branch, making online connections.

I became friendly with many of the UK’s leading activists. What I discovered shocked me. I had known that some activists held deep-rooted antisemitic feelings, but had no idea it was so common.

I found posts about “Zionists” being responsible for 7/7, 9/11, Charlie Hebdo and the Holocaust. I found Holocaust revisionism and denial. Nothing seemed beyond the scope of these activists. And it was everywhere.

What I wanted to do was quantify the level of hatred. I waited for a chance to analyse a gathering of activists and research how many of those who attend subscribe to hard-core antisemitic ideology.

The opportunity presented itself on February 6, when the PSC called for a mass demonstration to oppose Israeli Prime Minister Benjamin Netanyahu’s visit to London.

I identified more than 70 activists. Thirty-six had accessible social media accounts and 15 of those had posted conspiracy theories involving Zionists, the Mossad, Jews or Israel.

These are people involved with PSC branches, who man PSC stalls in the high street. Several times during the research, I came across footage of these activists in stores demonstrating against a shop stocking Israeli goods.

How different does that action look, when you realise it comes from someone who promotes antisemitic conspiracy theories?

The central finding suggests there is a correlation between antisemitism and the level of anti-Israeli activity, and that hard-core antisemitism is heavily represented at anti-Israel gatherings.

The real question is why unions, teachers, firefighters, politicians align with such a group.

If any organisation had a substantial following of people who talked about any other minority the way PSC members talk about Jews, nobody would go anywhere near them. The PSC have Jeremy Corbyn as a patron and the NUT and TUC treat them like close friends. This must change.

Given this research, we cannot pretend this is just a fringe element at protests. We need to change the lens through which we view these activists.

This isn’t about the Palestinians, nor about a humanitarian cause. We need to treat them accordingly.

David Collier is a researcher and blogger who focuses on antisemitism within UK based pro-Palestinian movements