A British rabbi has stepped into the controversy over the Conservatives’ allies in the European Parliament’s new centre-right group.

Rabbi Barry Marcus of London’s Central Synagogue has called into question the appointment of Polish MEP Michal Kaminski as chair of the European Conservative and Reformist Group (ECR), which now includes 25 MEPs from Britain’s Conservatives.

Rabbi Marcus says that Mr Kaminski was involved in a campaign to try to stop a Polish national apology being made in 2001. The year marked the 60th anniversary of a massacre of Jews in the town of Jedwabne in July 1941, which was carried out by Nazis and some Poles.

Polish right-wingers have long refused to accept involvement in the killings.

Rabbi Marcus said: “My stance is not a political one. I am raising the alarm because only 65 years after the most unspeakable tragedy on Polish soil and throughout Europe, there has been a right-wing resurgence which allows a person like Kaminski to be given prominence.

“We are sleep-walking towards another wave of antisemitism. We have given these people a hechsher (seal of approval.) All of us, and I include myself, want to believe that people of goodwill, sanity and common sense will see the danger and do something, and that all this will disappear by itself — but it won’t.

“David Cameron has been making overtures to the Jewish community. We need to say: ‘Why are you associated with people like this?’ The ideal thing would be to make a statement dissociating himself and the Tories from people like this.”

But Timothy Kirkhope MEP, the Conservative leader in Brussels and European chairman of Conservative Friends of Israel, said: “Mr Kaminski has already made it clear that he is pro-Israeli and pro-Jewish.

“His party has a record of fighting antisemitism that any party in Europe would envy. He was spokesman for President Kaczynski, who has been described by Ha’aretz as ‘a friend to the Jewish community’.

“Accusations of antisemitism against him are a political smear. Rather than these nasty tactics, our opponents should be debating with us about the reform we are leading in the EU.”

The 1941 Jedwabne massacre occurred when Polish people, together with the Nazis, rounded up the local Jewish population.

The Jews were mutilated and then driven into a barn where they were burned alive.

Sunday’s Observer said that in 2001 Mr Kaminski was quoted in a right-wing Polish newspaper as accusing Jews of harming Poland by collaborating with the Soviet forces during the Communist era.

The newspaper said that initially Mr Kaminski denied trying to block the 2001 apology, saying he was abroad, but later admitted he could not recall whether or not he was in Poland.