The Labour MP who labelled Ken Livingstone a “Nazi apologist” for saying that Hitler backed Zionism has said the decision not to expel him from the party “spits in the face” of Labour-supporting Jews.

John Mann, chair of the All Party Parliamentary Group Against Antisemitism, said the decision was an insult to “those pioneers and generations of Jewish Labour and trade union heroes who have been a cornerstone of Labour though its history.”

Writing for the JC, Mr Mann described the decision to extend Mr Livingstone’s suspension by one year as “one of Labour’s darkest hours”.

He added that he was “ashamed of my party” and said ”what happened yesterday has inspired racists and antisemites”.

He continued: “When this party was formed, my family helped set up the Leeds Labour Party at the turn of the last century, and at great personal cost due to the discriminatory practices of Liberal-supporting factory owners.

“Jewish workers were a fundamental part of that movement. This decision spits in the face of those pioneers and generations of Jewish Labour and trade union heroes who have been a cornerstone of Labour though its history.

“Livingstone and his politics have nothing in common with them, me or the Labour Party. I am ashamed of my party and I apologise to my parents, my grandparents and my great grandparents for what our party has become.”

Mr Mann revealed he had received a series of antisemitic emails in the wake of Tuesday night’s decision from “those most emboldened by it”, including claims he was in the pocket of the “Jewish lobby”.

But the MP for Bassetlaw called on supporters to “fight back relentlessly against the Jew-haters”.

He added: “The Labour Party should be a force for good – we will have to act.”

Mr Mann had confronted Mr Livingstone on the steps of the BBC Millbank studio in Westminster last April after he gave an interview in which he said Hitler had supported Zionism.

Angry Mr Mann called him a "Nazi apologist" and accused him of "rewriting history".