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”.