Seumas Milne, one of Jeremy Corbyn’s closest advisers, told a party worker to remove the Hebrew from a Passover greeting because it might look “Zionist”, it has been claimed.

Mr Milne, Labour’s executive director of communications, is said to have wanted to delete the wording “Chag Kasher VeSameach,”, which translates as “A Happy and Kosher Holiday,’ from Mr Corbyn’s Pesach message to the Jewish community.

According to Dave Rich, a senior official of the Community Security Trust, Mr Milne felt “the use of Hebrew implied support for Zionism”.

Writing in the New York Times today, Mr Rich, the author of a new book on antisemitism and the left, said that “after some debate, Mr Milne was overruled”.

But Labour said the claim Mr Milne had asked for the Hebrew to be removed was "categorically untrue".

In a statement, a spokesperson said the phrase had appeared in the message.

"Far from being overruled on its contents, it was Seumas Milne who signed off the full statement," the spokesperson said.

Labour said the claim was made by a "disgruntled former member of staff".

Joshua Simons, a Jewish activist who worked in Mr Corbyn’s office as a policy adviser for six months before quitting, has identified himself as the aide involved.

Writing on the Guardian website, he claimed he was instructed to remove the message by a senior official. He did not name Mr Milne.