A Labour activist who claimed the Israeli lobby had “manufactured” the party’s anti-Semitism crisis has been selected as a candidate for the European elections, deepening the row over claims of anti-Jewish hatred in the party.

Martin Mayer, a former member of Labour’s National Executive Committee and a Unite union activist, has been chosen to stand as MEP for Yorkshire & Humber.

The retired transport worker has been active in Labour Against the Witchunt (LAW), a group which claims accusations of anti-Semitism are a ruse to undermine Jeremy Corbyn.

Mr Mayer’s selection as an MEP candidate is likely to raise questions about the suitability of the candidates being selected by Labour and whether the party is still doing enough to tackle the issue of anti-Semitism in its ranks.

A report of a meeting of LAW in Sheffield last May said Mr Mayer had “shared fascinating stories from his time on the Labour Party NEC and the many ‘bogus’ claims of anti-Semitism he witnessed first hand”.

In 2016 Mr Mayer sent an email entitled “How Israel lobby manufactured UK Labour party’s anti-semitism crisis”.

In the email he complained that “Labour’s Blairite right wing have used the smear of anti-semitism to undermine Jeremy Corbyn’s leadership”.

Mr Mayer included an email from the activist Tony Greenstein - who was himself later expelled from Labour - condemning “the Zionist lobby” and accusing Mr Corbyn’s critics of “a dirty tricks operation” worthy of the CIA.

Labour leader Jeremy Corbyn, seen here campaigning in Lancashire last week, faces new claims the party is not taking a tough enough line on anti-Semitism credit: Danny Lawson/PA

Euan Philipps, of Labour Against Anti-Semitism, told The Telegraph: “‘The Labour Party is presenting candidates for public office whose apparently antisemitic views have no place in British democracy.

“Despite assuring the Jewish community that there is zero tolerance of antisemitism in his party, Jeremy Corbyn has failed to tackle the racial hatred that is now endemic across the Labour movement.”

In a statement Mr Mayer said: “When I was on the NEC I was shocked and appalled to see cases of antisemitism within our Party. I said back then and I say again now: it does exist within our Party, it is a problem, and we must not tolerate it.

“I was also concerned about factionalism undermining the integrity of the disciplinary processes and the fight against antisemitism. I regret the language I used to express this and I would not use it today. Since then, I have learnt a lot more about this subject and I realise that words like ‘smear’ have the effect of downplaying and dismissing this very serious issue.”

He added: “I did not deny the problem exists within our Party, and I believe anyone who denies it is contributing to the problem. As we’ve seen from the figures that the Party recently released, this is a small minority in our Party, but they must be kicked out.”

The Sunday Telegraph can today reveal that three more Labour councillors and candidates have recently posted material which appears to endorse the claim that accusations of anti-Semitism have been exploited by the ‘Israel lobby’ and Jewish groups in this country.

In a tweet last week responding to concerns raised by Wes Streeting MP about voters being put off Labour by claims of anti-Semitism, David Sheard, the deputy leader of Kirklees Council, retorted: “Jewish organisations run a concerted campaign against JC [Jeremy Corbyn] and Wea [sic] Streeting is not surprised that it is working.” Mr Sheard did not respond to a request for comment.

Eleanor Tristram, a candidate for Stafford Borough Council, shared a claim on Facebook that the Jewish MP Ruth Smeeth was funded by the ‘Israel lobby’ and also described the Labour anti-Semitism crisis as a ‘smear’ organised by “pro-Israel Labour MPs”.

Ms Tristram also shared a Facebook post that stated: ‘The current antisemitism witch-hunt against Chris Williamson, Jackie Walker and others, and against our own Labour Party constituencies is a fraud … The attacks, orchestrated by the right-wing of the Labour Party led by Tom Watson, reinforced by the MSM, are not really about antisemitism. They are a cover for sabotage … These pro-Israel Labour MPs know that such a government would oppose attacks on the Palestinian people.”

But responding to claims she was helping to spread anti-Semitic comments Ms Tristram told The Telegraph: “The current row over anti-Semitism is a witch hunt against Jeremy Corbyn. There is no problem with anti-Semitism in the party. I’ve not seen any examples of it at meetings of at party conference. It’s part of a campaign in the mainstream media to discredit the leadership.”

She added: “The majority of anti-Semitism directed at [Jewish members] has not come from Labour members and if it has they have been expelled.”

Mick Bone, a Labour candidate for Middlesbrough Council, shared a graphic suggesting that the Israeli Embassy controls BBC News, and that Jewish employees such as Dannny Cohen had dual loyalty to Israel.

Mr Bone has also shared Facebook memes calling for Israeli diplomats to be expelled from Britain and accusing the ‘Israeli lobby’ of leading a witch hunt against Corbyn. He refused to comment when contacted by this newspaper.

The Labour Party is now understood to be investigating the posts as a matter of urgency.

A spokesperson said: "The Labour Party takes all complaints of antisemitism extremely seriously and we are committed to challenging and campaigning against it in all its forms. All complaints about antisemitism are fully investigated in line with our rules and procedures and any appropriate disciplinary action is taken.”

It comes after the Telegraph revealed that Labour was last week forced to suspend Alexandrina Braithwaite, a council candidate, after we revealed she had posted a web of online Rothschild and Israel conspiracy theories.

She is understood to be the fourth Labour council candidate to have been suspended in the past two weeks over allegations of anti-Semitism.