Labour's deputy leader Tom Watson has said the party "shames us all" over its failure to expel Ken Livingstone over remarks about Hitler and zionism.
Watson said he finds it "incomprehensible" that Livingstone has not been expelled for suggesting Hitler supported zionism, and says he is "deeply saddened."
The former London Mayor has been suspended for another year rather than being thrown out of the party, over comments he made last year suggesting Adolf Hitler supported zionism.
Watson said: "It isn't just Jewish people who feel disgusted and offended by what Mr Livingstgone said and by the way he has conducted himself over this matter, and it isn't just Jewish Labour member who feel ashamed of any indulgence of his views anywhere in the Labour Party. This shames us all, and I'm deeply saddened by it.
"Mr Livingstone's unrepentant media appearances in recent days have continued to discredit the party I love. His current behaviour is still bringing the party I love.
"My party is not living up to its commitment to have a zero tolerance approach to anti-semitism. I will continue the fight to ensure that it does, and I will press my colleagues to do so too."
Watson's comments were echoed by a number of other MPs and Jewish groups.
Labour MP John Woodcock tweeted: "This pathetic Livingstone sentence is an important moment.
"Do we stand for decency or are we part of the decay?"
His fellow Labour MP, Wes Streeting, said on the social network: "So much for zero tolerance approach to anti-Semitism - this is a terrible betrayal of Jewish Labour supporters and our values."
Joe Glasman, of the Campaign Against Anti-Semitism, said: "Ken Livingstone has portrayed Jews as Nazis for decades. His claim Hitler acted in support of Zionism, alongside the constant repetition of this distortion, is a repulsive spectacle.
"We felt sure the Labour Party, blighted by anti-Semitism as it is, would reclaim some of its former self and expel him. Labour has long had a moral duty to expel Ken Livingstone, but instead it has allowed his vile views to gain support in the party."