A “landmark” victory for freedom of expression has been claimed by a regional daily after a row over a massacre of Jews was played out on its letter pages.

The Belfast Telegraph was told it had no case to answer after the argument, which involved the Polish Ambassador to the UK and a member of the Northern Ireland Assembly, led to a complaint to the press regulator.

The complaint to the Independent Press Standards Organisation arose from a letter published by the Bel Tel from reader Dr Kevin McCarthy, in which he accused Poland of historical “deeply entrenched anti-Semitism”.

The issue was brought up after a letter by John Dallat, the SDLP MLA for East Londonderry, was published in which he referred to a visit to the “Auschwitz-Birkenau concentration camp in Poland” as part of a wider criticism of the flying of Nazi flags in the town of Carrickfergus.

This prompted a response from the Polish Embassy in London, pictured above, which said the phrase was inaccurate “as during the Second World War, Poland was occupied by Nazi Germany and the USSR”.

Consequently, Auschwitz was not “in Poland, but rather on the German-occupied Polish territories”.

In turn, Dr McCarthy sent in a letter which argued that, while it was “technically correct” that Auschwitz-Birkenau was in Nazi German-occupied Poland and not under the control of a sovereign Polish government, “the Nazis knew that Poland, with its deeply entrenched anti-Semitism, was arguably the only place under its control that would accept such an extermination centre”.

As an example of “Polish historical anti-Semitism”, Dr McCarthy cited the Kielce massacre of July 1946 in which 42 Jews, many of them survivors of the concentration camps, were killed.

According to the Bel Tel the letter provoked an online campaign by the worldwide Polish community in which Dr McCarthy received threats in the post and the Dublin Jewish Museum, where he had previously lectured, was targeted.

A namesake at University College Cork, who had no connection to the row, received menacing emails.

The Polish Ambassador to London, Witold Sobkow, wrote to the Bel Tel asking it to remove the letter from its website and publish a correction, a request it denied.

A reader living in Dublin, Adam Augustyn, then complained to IPSO that the newspaper had breached the Editors’ Code in publishing Dr McCarthy’s views, because, he believed, the academic had no evidence to support his claims.

But IPSO responded: “The publication had not failed to distinguish between comment, conjecture and fact and, as such, your complaint did not raise a possible breach of Clause 1.”

Bel Tel editor Gail Walker said: “The Independent Press Standards Organisation’s ruling is doubly welcome.

“Not only does it reflect the – surely common-sense – position that editors don’t agree with every opinion that appears in their letters page, or, indeed, any other page.

“It also underscores newspapers’ vital role in identifying comment, conjecture and fact – and the right of a free press to publish all three.”

While IPSO has not brought the case forward from Mr Augustyn, several other complaints about Dr McCarthy’s letter are currently being investigated under Clauses 1 (Accuracy), 2 (Opportunity to Reply) and 12 (Discrimination) of the Editors’ Code of Practice.