Jeremy Corbyn faces a fresh row over his handling of Labour's relationship with the Jewish community.
Here we look at some of the key questions:
Labour leader Mr Corbyn has acknowledged that anti-Semitism occurred in "pockets" within the party and wider movement.
A report into the issue by Baroness Chakrabarti in 2016 found that "the Labour Party is not overrun by anti-Semitism", but it was condemned as a "whitewash" by critics.
The pro-Corbyn Momentum group said the problem is "more widespread in the Labour Party than many of us had understood even a few months ago".
The Labour leader, like many on the left of the party, has a long history of supporting the Palestinian cause and criticising the government of Israel for human rights abuses.
But some of those who share Mr Corbyn's political sympathies have crossed the line from attacking the Israeli government to smears aimed at Jews - including holocaust denial.
In March, the Board of Deputies of British Jews and Jewish Leadership Council used an open letter to claim that Mr Corbyn is "repeatedly found alongside people with blatantly anti-Semitic views, but claims never to hear or read them" and "rightly or wrongly, those who push this offensive material regard Jeremy Corbyn as their figurehead".
The issue has never really gone away, but flared up again after Labour MP Luciana Berger challenged Mr Corbyn over his apparent support for an artist behind a mural at the centre of an anti-Semitism row.
The Labour leader admitted he should have looked more closely at the content of the picture before defending it on freedom of expression grounds.
The ensuing row led to a protest outside Parliament and the strongly-worded open letter.
The Labour leader issued an apology for the "pain and hurt" caused by anti-Semitism in the party, and promised to meet representatives from the Jewish community.
But he faced a backlash after attending a Seder event with the radical Jewdas group, which claimed that the mural row had been a "malicious ploy" aimed at undermining Mr Corbyn.
The Board of Deputies of British Jews is made up of almost 300 deputies directly elected by synagogues and community organisations and describes itself as the "voice of the British Jewish community".
The Jewish Leadership Council is a charity which aims to support a vibrant and safe Jewish community.
Jewdas is a radical, left-wing group which has been critical of Zionism and the Israeli government and attacked the reaction of the "Jewish establishment" to the Labour anti-Semitism row.
The Jewish Labour Movement has been affiliated to the Labour Party since 1920 and its members include parliamentarians, councillors, grassroots activists and party supporters.
Mr Corbyn has asked for an urgent formal meeting with the Board of Deputies and the Jewish Leadership Council to discuss tackling anti-Semitism.
Labour also has to deal with a backlog of cases of alleged anti-Semitic behaviour, including deciding whether Ken Livingstone has a future in the party.
New general secretary Jennie Formby has promised an updated complaints and discipline process to eradicate the "stain" of anti-Semitism.