A total of 107 MPs, along with 48 Labour peers, put their name to the Jewish Labour Movement statement criticizing the party’s National Constitutional Committee (NCC) for handing former London Mayor Ken Livingstone an additional one-year suspension from holding office in the party but reinstating him as a member, pushing the party to announce a new investigation into the matter.
On Thursday, UK’s Prime Minister Theresa May accused the Labor Party of "betraying" the Jewish community by letting Ken Livingstone "off the hook."
"It could not be clearer that the Labor Party is now a long way away from the common, centre ground of British politics today," May added.
Livingstone was suspended from holding party office a year ago after claiming Hitler supported Zionism in the 1930s before he "went mad and ended up killing six million Jews." On Tuesday Labour officials extended his suspension for another 12 months.
Livingstone, who has repeatedly asserted collaboration between Zionists and Nazis before World War II, said the party hearing had been "like sitting through a court in North Korea."
He said he would appeal his suspension.
Chief Rabbi Ephraim Mirvis said Labour "has yet again failed to show that it is sufficiently serious about tackling the scourge of anti-Semitism."
Karen Pollock, chief executive of the Holocaust Educational Trust, said Livingstone's suspension was "a slap on the wrist for a serial offender.
Allegations of Labour anti-Semitism have grown since pro-Palestinian socialist Jeremy Corbyn was elected leader of Britain's main opposition party in 2015.
Some in the left-of-center party say Corbyn, a longtime critic of Israeli actions against the Palestinians, has allowed abuse to go unchecked.
Deputy leader Tom Watson said the failure to expel Livingstone "shames us all, and I'm deeply saddened by it."
"My party is not living up to its commitment to have a zero-tolerance approach to anti-Semitism," Watson said. "I will continue the fight to ensure that it does, and I will press my colleagues to do so too."
Amid the growing furor, Corbyn said the party's governing executive council would investigate comments made by Livingstone in the wake of his suspension.
Corbyn said "it is deeply disappointing that, despite his long record of standing up to racism, Ken has failed to acknowledge or apologize for the hurt he has caused."
Corbyn, a longtime ally of the former mayor, said "Ken Livingstone's comments have been grossly insensitive, and he has caused deep offence and hurt to the Jewish community."
Livingstone, however, remained defiant.
“Today’s Labour Party panel extended my suspension for another year because of my political views, not because I have done anything to harm the Labour Party,” he said.