There have now been half a dozen national news stories about Labour Party members, including two councillors and a parliamentary candidate, being exposed for making antisemitic remarks.

I declare an interest in that I am not Jewish but I’m a Zionist (literally meaning someone who supports Jewish national self-determination through the creation and existence of a Jewish State in Israel) and my day job is running a pro-Israel campaign group, We Believe in Israel, so I am very conscious of where the boundary lies between legitimate criticism of Israel and antisemitism.

It’s apparent from the reactions to the recent cases that many people in the party are unaware of or in denial that antisemitism (prejudice and hatred towards Jewish people) can exist as a left phenomenon, and if they do accept it, confused about which aspects of extreme anti-Israel rhetoric are offensive.

It’s easy for people on the left to understand the reality of far right antisemitism because we are all familiar (or should be) with the history of the rise to power of the Nazis and the Holocaust. It makes sense to us as leftists because clearly the Nazis were a common enemy to both Jews and socialists and that the same goes for modern day neo-Nazis like the BNP.

Things get a bit more difficult with religious/cultural antisemitism. This isn’t something that makes sense to most of us on the left because our own secular values mean we often don’t have much knowledge of these phenomena. But it doesn’t take much study to discover there are deep undercurrents of antisemitism in both Christian history (the concept of the Jews as killers of Christ and the idea in “replacement theology” that they therefore lost God’s covenant and were replaced by the Christian church) which drove pogroms from the Middle Ages onward; and in Muslim history (negative references to Jews in the Koran, dhimmis restrictions on Jews living under Muslim rule, and in extreme Islamist thinking, e.g. the Hamas charter, overt calls to kill Jews). Of course, most people who are contemporary followers of these religions don’t buy into these views, but a minority do.

But most of us on the left are blissfully ignorant of the long history of antisemitism in our own ranks. We like to delude ourselves that we are pure, and good, and incapable of racism. But sadly there’s a long history of prejudice and hatred towards Jews on the left, and no tradition is immune from it. In the orthodox Communist tradition Stalin was notoriously and overtly antisemitic, promoting wild conspiracy theories about Zionists and “rootless cosmopolitan” Jews, which given his propensity to have people shot or deported to the Gulag, often had a lethal effect.

Some groups in the Trotskyist tradition have employed antisemitic imagery. On Labour’s right, Ernie Bevin, a man I would otherwise see as my hero because of his role founding the TGWU union, NATO and the British nuclear deterrent, handled the crisis in Mandatory Palestine that led to Israel’s creation with ill-disguised antisemitic prejudice towards the Jews.

I don’t know the extent of antisemitic views within the Labour Party. I don’t think the half dozen cases so far are likely to be the end of it. I think the rhetoric around the Israel/Palestinian conflict has become so inflamed and black and white in recent years that a significant number of people both from the hard left and Labour people whose values are informed by particular versions of Christian or Muslim thinking have started to cross the line between anti-Zionism and antisemitism. The leadership election last year brought many people from a far left milieu into or back into the Labour Party and it is simple fact that the prevalence of antisemitic versions of anti-Zionism is higher the further left you go.

But even if it was just half a dozen cases, that’s half a dozen too many to tolerate in a party dedicated to equality and anti-racism, and half a dozen more than the reputation of our party and all the noble things it stands for and has done can stand the stain of.

The contemporary debate about Israel is a difficult area because Israel is both at the heart of a complex conflict with the Palestinians, which is one of the most contentious issues in global politics, with contradictory national narratives on each side; and it’s the world’s only Jewish State, perceived by the vast majority of Jews globally as being the fulfilment of aspirations to national liberation, a lifeboat that secures the Jewish people against any repeat of the Holocaust, and somewhere Jews feel a deep cultural, family and religious connection to.

There are many political activists – including many Zionists – who are able to criticise Israeli policies and politicians, to oppose the occupation of the West Bank, the building of settlements, or the manner in which Israel has conducted military operations in Gaza, using language that does not cause distress to Jews.

There are some political activists – including some Jews – who are anti-Zionists in the sense that they think a Jewish State is a mistake and they want to persuade Israeli Jews towards a one state solution with the Palestinians, and manage the more difficult political balancing act of doing this using language that does not cause distress to Jews (it’s quite difficult not to distress people when you are urging them to forego their right to national self-determination, unless you are an anarchist or communist and deny the concept of nation states full-stop, not just for the Jews. If you are denying self-determination to Jews and want the only Jewish state gone the onus is really on you to explain why that isn’t antisemitic as the result is deeply offensive to most Jews.).

As the Community Security Trust (CST), the British Jewish Community’s charity for tackling antisemitism says “Not all anti-Zionists are antisemites and anti-Zionism is not necessarily antisemitic.”

By the way, if you don’t think antisemitism is a real threat today, please explain why Jewish schools and synagogues have to be guarded by CST volunteers.

Perhaps the best approach to testing whether your rhetoric on Israel is antisemitic is to put yourself in the shoes of a Jewish person and try to think how they would feel about the remarks that have been attributed to the various people recently suspended by the Labour Party, and other discourse on social media. Which of them would you find offensive or hurtful? Which of them would make you think the person making them was prejudiced against you as a Jew, not just Israel as a state? It was established by the MacPherson report that the most important thing when looking at allegations of racism is to understand how the victim perceives the case. The All Party Parliamentary Inquiry into Antisemitism said “We take into account the view expressed in the Macpherson report of the Stephen Lawrence Inquiry that a racist act is defined by its victim. It is not acceptable for an individual to say ‘I am not a racist’ if his or her words or acts are perceived to be racist. We conclude that it is the Jewish community itself that is best qualified to determine what does and does not constitute antisemitism.”

The easiest examples are when former Woking parliamentary candidate Vicki Kirby talked about Jews having “big noses” and when Luton councillor Aysegul Gurbuz’s Twitter feed praised Hitler as the “greatest man in history”. It should be fairly obvious these are examples of antisemitism.

But antisemitism can also come into the debate about Israel when people use language and images that are drawn from historic antisemitic tropes that were previously applied to Jews per se, and use them to attack the only Jewish State:

Claims of Jewish or Zionist conspiracy theories, Jewish or Zionist control of the media, finance and political processes, for instance saying Israel controls Isis or Israel controls US or British foreign policy. This sort of stuff is straight out of the “Protocols of the Elders of Zion”, a forgery produce by Tsarist secret police.

Claims that British Jews have a dual loyalty that means they are more loyal to Israel than to the country they are citizens of.

Allegations that Israel is acting like the Nazis, that events in Gaza or the West Bank constitute a Holocaust, that Gaza is a concentration camp. This is Holocaust Inversion – telling the Jews who were the victims of the Holocaust that they are the new Nazis. I can’t think of anything more grotesque. These Nazi analogies are deeply hurtful to all Jews and designed to cause maximum distress.

Substitution on placards at demos or on social media memes of swastikas for Stars of David. As CST’s Dave Rich said last year “Don’t you find it odd that the only political demonstrations where it is considered OK by people on the Left to wave a swastika, just happen to be protests against the world’s only Jewish state? That’s an almighty coincidence.”

Use of language such as “baby killers” to describe Israeli military actions, when this has echoes of the Blood Libel, the mediaeval Christian myth that Jews killed gentile babies to use their blood to make Passover matzo bread, which was often used as the catalyst to start pogroms.

Denial of Jewish peoplehood and historical connection to Israel – including the allegation that Ashkenazi (European) Jews have no genetic connection to Middle Eastern Jews and are not “real Jews” but stem from some mass conversion in the Dark Ages.

Use of Zionism, Zionist and “Zio” not to describe simple belief in Jewish rights to a state but as an insult implying conspiratorial power and evil intent (exactly mirroring traditional antisemitic images of Jews).

Dehumanising and demonising language that was historically used against Jews being deployed against Israel and Zionists e.g. “bacteria, rats, cancer, plague”.

Signalling out Zionism and Israel as uniquely illegitimate when you don’t target any other forms of national movement or country.

Just swapping the word Zionist in instead of Jew isn’t a get out clause for using old-fashioned antisemitic tropes. As CST say: “Employing the word ‘Zionist’ where the word ‘Jew’ would have previously appeared in open antisemitic discourse may, or may not, be deliberate obfuscation on the part of the user. Nevertheless, it essentially fulfils the same psychological and political purpose as open antisemitism once did.”

Some harsh and unfair criticism of Israel is not antisemitic. I hate the attempts to compare Israel to apartheid South Africa. Professor Alan Johnson has comprehensively rebutted this smear here. But whilst it is an unfair allegation, and I will fight it politically because it is part of an effort to delegitimise Israel, it isn’t an inherently antisemitic one.

I expect people to advocate passionately for the Palestinians and to have heartfelt criticisms of Israel.

But if you find yourself discussing Israel using images or language that could just as easily come from a Nazi or Stalinist or Tsarist antisemitic pamphlet, and that are likely to cause your Jewish fellow citizens to feel distress or even fearful, you have crossed a line. And you definitely don’t belong in a modern democratic socialist party that prides itself on anti-racism.