Jeremy Corbyn's adviser Andrew Murray has appeared to suggest the chief rabbi's intervened in the General Election because he was being used by the "bourgeoisie" to defeat Labour.
Mr Murray wrote in Tribune Magazine that "the bourgeoisie... threw all its considerable resources" to ensure Labour's historic defeat in December, "from the mass media to nominally retired security officials to religious leaders".
People on Twitter said the meaning of "religious leaders" could only be Chief Rabbi Ephraim Mirvis, who took the unprecedented step of attacking Labour antisemitism during the election campaign.
The Chief Rabbi wrote in the Times: "The claims by leadership figures in the Labour Party that it is 'doing everything' it reasonably can to tackle the scourge of anti-Jewish racism and that it has 'investigated every single case' are a mendacious fiction...
"How complicit in prejudice would a leader of Her Majesty’s opposition have to be in order to be considered unfit for high office?"
Among those to support the chief rabbi was the Archbishop of Canterbury, who said: "That the Chief Rabbi should be compelled to make such an unprecedented statement at this time ought to alert us to the deep sense of insecurity and fear felt by many British Jews.
"They should be able to live in accordance with their beliefs and freely express their culture and faith.”
Mr Murray, a former Communist Party member and chair of Stop The War coalition, wrote in Tribune: "The bourgeoisie... threw all its considerable resources, from the mass media to nominally retired security officials to religious leaders, into securing the defeat of the Corbyn project which, since the 2017 election, had posed a realistic threat to their power and at least some of their property."
Mr Murray was seconded to Mr Corbyn's office part-time from the Unite union, where he is chief of staff, during the 2017 General Election and retained afterwards as a part-time adviser on Brexit.
His daughter Laura Murray is Labour's head of complaints.