A growing backlash against the decision to suspend, rather than expel, Ken Livingstone over controversial remarks on Adolf Hitler and Zionism has engulfed the Labour Party.

As more than 30 Labour MPs publicly attacked the ruling of the party’s disciplinary panel, deputy leader Tom Watson condemned the decision, saying: “This shames us all.”

Labour’s shadow attorney general Shami Chakrabarti said she was “horrified” by the way Mr Livingstone had behaved in the aftermath of the move, and warned this could be grounds for renewed action against him.

Shadow Brexit secretary Sir Keir Starmer insisted Mr Livingstone should have been expelled, as other MPs called on the party’s National Executive Committee to review the decision.

Mr Watson’s outspoken condemnation of the “incomprehensible” ruling came after the Chief Rabbi accused the party of “failing the Jewish community” by not expelling the ex-London mayor over the controversial remarks.

Chief Rabbi Ephraim Mirvis said: “This was a chance for the Labour Party to show that it would not tolerate wilful and unapologetic baiting of the Jewish community, by shamefully using the Holocaust as a tool with which to inflict the maximum amount of offence.”

Mr Watson said it is “incomprehensible” that members of the panel “found Ken Livingstone guilty of such serious charges, and then concluded that he can remain a member of the Labour Party”.

The deputy leader said: “When I read the words of Chief Rabbi Mirvis, who says that ‘the Labour Party has failed the Jewish community, it has failed its members and it has failed all those who believe in zero-tolerance of anti-Semitism’, I can’t disagree with him.

“I wish I could, but I can’t. I am ashamed that we have allowed Mr Livingstone to cause such distress.

“This shames us all, and I’m deeply saddened by it.”

Ms Chakrabarti said: “I am horrified by Ken Livingstone’s lack of contrition and repeated offence which could be potential grounds for further investigation by the party.”

Sir Keir told the BBC: “I think he should have been expelled. As far as I’m concerned there should be zero tolerance, backed up with robust actions.”

Ex-Labour leader Ed Miliband tweeted: “Equivocation about anti-Semitism or rewriting Nazi history can have no place in Labour.

“I am appalled that even now Ken shows no real remorse. His status should be revisited in the light of his continuing offensive behaviour.”

Labour’s former foreign secretary David Miliband told BBC Radio 5 Live: “One of the reasons I grieve for the state of the Labour Party is I never believed we would see the day when anti-Semitism and Labour were being discussed in the same sentence. That is an unspeakable state of affairs.”

Wes Streeting said he would back any move by concerned fellow Labour MPs to write to the party’s National Executive Committee asking it to review the decision.

Mr Streeting told the Press Association: “This decision of the National Constitutional Committee has to be reported to the NEC and I think they need to step in.”

Mr Livingstone has vowed to campaign against his suspension for a further year, insisting he had told the historical truth, and would now consult lawyers on his legal position.

“You can’t apologise for telling the truth. I will be launching a campaign to overturn my suspension of party membership.”

The Labour veteran was suspended in April last year after claiming Hitler supported Zionism in the 1930s before he ”went mad and ended up killing six million Jews”.

Mr Livingstone insisted he had never said Hitler was a Zionist, only that Hitler had supported Zionism at one time.