Tell somebody that, a few decades ago, Polish Jews were accused of disloyalty, called a “fifth column” and forced out of their jobs and homes, while Jewish communities elsewhere lobbied their governments to open their doors to Jewish refugees from the East, and they’ll probably think of the antisemitic propaganda and discrimination that preceded the Holocaust.

But this is also a post-war story of antisemitism from a Polish government that claimed to be socialist, and it resulted in a secret agreement between the British government and the Board of Deputies to relax entry requirements for Polish Jews seeking sanctuary in this country.

This year is the 50th anniversary of the 1968 antisemitic campaign that saw half of Poland’s remaining Jewish population leave the country. Early in 1968 a student protest movement gathered momentum in Poland as it did in many countries that year, and Poland’s Communist government responded with an antisemitic campaign to quash it.

The initial protests had nothing to do with Jews, Israel or Zionism, but two prominent students who were arrested in one of the first protests were Jewish, and antisemitism provided a familiar and reliable way for the authorities to respond.

A list of mainly Jewish names of the alleged instigators of the protest movement was passed to the media.

Wladyslaw Gomulka, first secretary of the ruling Polish United Workers’ Party, had previously identified Zionists as a “fifth column” in Polish society, in a speech shortly after the Six Day War.

In March 1968, in a long speech about the protests, he explained that there were three types of Jews: Zionists who are loyal only to Israel; “cosmopolitans” who feel loyalty neither to Poland nor to Israel, and those who hold genuine loyalty to Poland.

Gomulka claimed the Communist Party rejected antisemitism, which he defined as being against Jews simply because they are Jews, but warned that Zionists would have to leave Poland while cosmopolitans, being people of suspect loyalty, shouldn’t hold any post of national importance.

Meanwhile, tens of thousands of political meetings and rallies were arranged all over the country, with slogans such as “down with the Zionists”, “purge the Party of Zionists” or “Zionists to Israel.” Anti-Zionist resolutions were passed in workplaces and at party meetings, while newspaper articles expounded the theory that a Zionist conspiracy lay behind the student protests.

Needless to say, this allegation was completely baseless. Only around 30,000 Jews remained in Poland in the 1960s from a pre-war population of over three million. There was no Zionist movement to speak of and the accusation that Polish students were guided by Israel, acting as an agent of international imperialism, was ridiculous.

Nor was this “anti-Zionism” anything to do with opposing actual Israeli policies or campaigning for Palestinian rights. Instead, “Zionist” was used as a euphemism for “Jewish”, while also serving as a useful label to stigmatise political opponents whether they were Jewish or not.

Typically, political antisemitism of this kind has a purpose that has little to do with Jews themselves: in this case, the regime’s reassertion of its authority in the face of a protest movement calling for greater freedoms. By associating the protests with Jews, the government hoped to minimise support for it among the broader Polish population.

The campaign played on traditional Polish antisemitism, which had long portrayed Jews as treacherous and representing a hidden threat to the Polish nation. It was, in the words of Polish historian Dariusz Stola, a “verbal, symbolic pogrom”.

This pogrom may have been symbolic, but its impact on the lives of Poland’s remaining Jews was very real. Many Jewish members of the Communist Party were purged, around 9,000 Jews lost their jobs and many also lost their apartments. Several committed suicide.

The number of Polish Jews applying to leave the country shot up — but even here, the regime had an antisemitic card to play. Those Jews who wanted to emigrate had to fulfil two conditions: they had to formally declare Israel as their destination (wherever they were actually intending to go) and they had to give up their Polish citizenship.

This was the final twist of the knife. In order to escape the antisemitic campaign, Polish Jews had to “prove” its central charge, by effectively admitting that their true loyalty lay with Israel.

Around half the 30,000 Jews living in Poland at the beginning of 1968 had left by 1971, less than a third of whom went to Israel.

British Jews watched with alarm as their Polish co-religionists once again found themselves in peril. In May 1968, the Board of Deputies, the Association of Jewish Ex-Servicemen and Women and the Inter-University Jewish Federation (the forerunner of today’s Union of Jewish Students) led a march of 2,000 people to the Polish embassy in London, under a banner proclaiming “British Jewry demands human rights for Poland’s Jews”.

In November, student Jewish societies around the country wrote to the British government calling on it to support Polish Jews. Several students’ unions passed motions, while the Board and the World Union of Jewish Students met the Labour Foreign Secretary, Michael Stewart, to press their case.

While politicians were generally sympathetic, the same cannot be said of all their civil servants. The Foreign Office’s Oliver Miles complained of “a complete lack of perspective where anything Jewish is concerned”, particularly in distinguishing between anti-Zionism and antisemitism, and felt that Polish antisemitism was largely due to “the fact that there were so many Jews in the Party apparatus just after the war.”

Another civil servant, when asked by the British embassy in Warsaw about Polish Jews wanting to emigrate to the UK, replied huffily that “in the establishment of the ‘Promised Land’, the lives of many British soldiers and civilians fell to the bullets and bombs of Jewish terrorists in the period up to 1948”.

Officials were not ignorant of the persecution and humiliation of Polish Jews and received detailed accounts from the embassy in Warsaw. Some even experienced Polish antisemitism first-hand. One Polish diplomat in London told his British counterpart that “the Nazi persecution of the Jews had been one of the best things that could possibly happen from the point of view of Zionism”. Jews are loyal “to their race and to Israel”, the Polish official explained, but now, thankfully, it was possible “to criticise a Jew without being accused of antisemitism”.

Nevertheless, the lobbying bore fruit in January 1969 when Home Secretary James Callaghan told the Board that he would “ease the path for those Jews in Poland who are suffering hardship at present, who wish to settle or work here, and for whom the United Kingdom is particularly appropriate as the country of settlement.” It is not known how many Polish Jews came to Britain as a result — the government had no idea how many had already entered the UK, or were waiting to do so — and Callaghan asked the Board to keep this act of generosity secret.

The Polish anti-Zionist campaign of 1968 was hardly an isolated example of antisemitism in the Soviet bloc during the Cold War.

Soviet antisemitic anti-Zionism combined traditional ideas about Jewish conspiracy, treachery and disloyalty with modern allegations of Israeli racism, fascism and colonialism. It outlived Stalin and became a staple of Soviet, and broader left wing, anti-Zionism.

As Polish Jews found out in 1968, this antisemitic rhetoric, in the guise of progressive anti-Zionism, could easily be turned into a campaign of harassment, vilification and isolation that ripped what was left of the Jewish community apart.

Dr Dave Rich is head of policy for the Community Security Trust, Associate Research Fellow at the Pears Institute for the Study of Antisemitism, and author of ‘The Left’s Jewish Problem: Jeremy Corbyn, Israel and Antisemitism’