A Jewish representative who walked out of a Spanish Civil War commemoration after a speaker compared the struggle against Franco’s Fascists to the Palestinian fight against Israel has described the organiser’s response as “a betrayal”.

Martin Sugarman, the historian and archivist for the Association of Jewish Ex-servicemen and Women (Ajex), was at the event on Saturday on London’s South Bank, which is organised by the International Brigade Memorial Trust (IBMT).

He has demanded a public apology be made following the incident and accused the IBMT of defending antisemitism.

During the ceremony, Tosh McDonald, president of train drivers’ union Aslef, gave a speech in which he compared the Palestinian struggle against Israeli “oppression” with the republican cause in Spain.

In response to this, Mr Sugarman said he “stood up, with no microphone, in front of about 300 guests in the open air and stated loudly and clearly that I was leaving in protest and would not be laying my wreath for the Jewish veterans from the Jewish community, which I held up so all could see, as he had inappropriately politicised the event with other issues which many people have different views on”.

Mr Sugarman, author of Fighting Back: British Jewry’s Military Contribution in the Second World War, has laid a poppy wreath for more than 20 years in memory of the Jewish volunteers.

More than 6,000 members of the International Brigade were Jewish, including nearly 400 from Britain and 500 from what was then British Mandate Palestine.

Some went on to fight in the Palmach, the predecessor to the Israeli Defence Force.

In a statement later released by the International Brigade Memorial Trust, the organisation said: “Tosh expressed the view that, just as the Spanish Civil War had been the great cause of young people in the 1930s, or that the anti-apartheid campaign had been the great cause of his generation, the plight of the Palestinian people was the equivalent great cause for many young people today.

“During the speech, Tosh also clearly and unequivocally denounced antisemitism and said it had absolutely no place in the Labour movement.

“The IBMT has never restricted or vetted the words of guest speakers. There are varying shades of opinion within the Labour movement on many contemporary political issues, in particular on wars and conflict in the Middle East.

“As a registered charity, the IBMT has to be strictly neutral on all such contemporary political issues. Our mission is to preserve the memory and spirit of anti-fascism and international solidarity that motivated the volunteers to join the International Brigades”.

Writing in response to this statement, Mr Sugarman, who described himself as “a proud Socialist but also a Zionist” said it was “at best a disappointment, at worst a betrayal”.

“You seem to forget that antisemitism is in the eye of the victims not the perpetrators… on many occasions non-Jews have no idea when and if they are being racist or antisemitic,” he said.

“For them/you, this may all be just an academic exercise; for us it is literally life and death, here or in Israel.

“Tosh McDonald of Aslef made a direct comparison between Franco's Fascists and Israel via a vis the Spanish Republic and the Palestinians. In other words, in case I am not clear, he was saying that in the same way that decent people supported the Republic against the Fascists in the 1930s, so today they/we should support the Palestinians against Israel.

“This totally concurs with antisemitism as defined by the EU, UN and other definitions accepted world-wide that to conflate Israel/Zionism, with Fascist/Nazism, is racist antisemitism.

“Typically McDonald covered his tracks by first stating he is against antisemitism. Then he makes an antisemitic statement. Does he think we are stupid? Are you seriously suggesting this lets him off the hook?  I suppose 'some of his best friends are Jews' as well.

“By defending McDonald you put yourselves in his camp. It is very simple.

“And so the IBMT is in breach of its Charity Commission brief not to be overtly political but remain neutral. This speech was no neutrality.

“I no longer feel able to join you again unless I get the stated apology I insist on next year read out in public, loud and clear.”