Sadiq Khan received a standing ovation for his speech to the Board of Deputies' annual dinner when he vowed to ensure Labour "repairs its relationship with the Jewish community".
Addressing a 450-strong audience that included cross section of rabbis and fellow Labour politicians on Monday, the London Mayor said that the breakdown in trust between British Jews and his party was "deeply disappointing".
“It pains me to my core when I hear that many Jewish people now feel that a party, that would normally be their natural home, doesn’t have their best interests at heart. And even worse, that Labour looks reluctant to tackle antisemitism from within the party itself,” he said.
“It’s simply not good enough. I’ve said it before, and I’ll say it again tonight, the Labour party has been far too slow to act."
He criticised Labour for initially refusing to adopt the International Holocaust Remembrance Association's (IHRA) definition of antisemitism in full, prompting a drawn out row over the summer.
"Labour should have adopted the full international definition of antisemitism right from the beginning, no ifs, no buts.
“I know there’s a long way to go to heal the mistrust and hurt that’s been caused. But the Labour leadership needs to make a concerted effort to rebuild the relationship with the Jewish community, and my pledge to you is that I will use my influence within the Labour party to ensure this happens.”
“It’s simply not good enough. I’ve said it before, and I’ll say it again tonight, the Labour party has been far too slow to act."
He called out the "truly shocking" abuse faced by Jewish Labour politicians - some of whom were in the audience.
Also in the audience from Labour was Emily Thornberry, shadow foreign secretary and a senior ally of Jeremy Corbyn.
"We often hear people say 'we must learn from our history'. Well, the moment we show we've learned these lessons is now," he said.
"I believe we must encourage everyone of all faiths and backgrounds to play their part. By the way, this include politicians in this country and around the world refraining from playing on people's worst instincts and using the language of division to advance their political cause."
Earlier, Board President Marie van der Zyl used her speech to call out Mr Corbyn's "tolerance of antisemitism".
The Board president also listed a number of Labour MPs, many of whom were in the audience, whom she described as “some of the community’s heroes, who have stood up to the worst abuse and kept on fighting".
She name checked Dame Margaret Hodge, Joan Ryan, Wes Streeting, Mike Gapes, Luciana Berger, Ian Austin, Ruth Smeeth and Dame Louise Ellman.
Mrs van der Zyl said she had “a message" for the Labour leader.
“You know exactly what you need to do. You know, because we have told you time and time again – enough of your tolerance for hatred against our community, kick out the racists from your party, disown your friendships with terrorists and Holocaust deniers. Mr Corbyn – enough is enough.
“We expect our politicians of all parties to stand up to racism and to build a society that works for everyone – a society for the many, and for the Jew.”
