The Conservatives have accused Labour of having a "very real problem with anti-Semitism" after a damning independent report said Jeremy Corbyn failed to provide leadership in tackling the issue.
The cross-party Home Affairs Select Committee questioned whether the Labour leader "fully appreciates" the nature of post-war anti-Semetism and criticised the inquiry into the issue by Labour peer Baroness Chakrabarti.
It accused the party of "incompetence" over its handling of allegations of anti-Semitism by party members including former London mayor Ken Livingstone and former Momentum vice-chairwoman Jackie Walker.
"The failure of the Labour Party to deal consistently and effectively with anti-Semitic incidents in recent years risks lending force to allegations that elements of the Labour movement are institutionally anti-Semitic," the report said.
The MPs said the Chakrabarti report was "clearly lacking in many areas" and questioned the independence of the inquiry after she joined the Labour Party and accepted a peerage as a nominee of Corbyn.
"The fact that the report describes occurrences of anti-Semitism merely as 'unhappy incidents' also suggests that it fails to appreciate the full gravity of the comments that prompted the inquiry in the first place," the MPs noted.
Conservative MP Mike Freer called for concrete action to stop the racist abuse of Jewish people within the party's ranks.
"The Committee's report has made it crystal clear that the Labour Party has a very real problem with anti-Semitism," he said.
"There is no place whatsoever for racism in British society.
"As leader of the Labour Party, Jeremy Corbyn has a duty to face up to the problem and to take concrete action to stamp it out now - not just make mealy-mouthed condemnations."
Responding, Corbyn said the report was biased against Labour and said criticism of Lady Chakrabarti was "unfair".
He said that the committee "violated natural justice" by refusing her request to appear before it.
He said: "Although the committee heard evidence that 75% of anti-Semitic incidents come from far-right sources, and the report states there is no reliable evidence to suggest anti-Semitism is greater in Labour than other parties, much of the report focuses on the Labour Party.
"As the report rightly acknowledges, politicising anti-Semitism - or using it as a weapon in controversies between and within political parties - does the struggle against it a disservice."
Corbyn gave evidence to the committee but MPs questioned his understanding of the issue.
"While the Labour Leader has a proud record of campaigning against many types of racism, based on the evidence we have received, we are not persuaded that he fully appreciates the distinct nature of post-Second World War anti-Semitism," the report said.
It added that Jewish Labour MPs had been subjected to "appalling" levels of abuse including death threats from individuals claiming to be supporters of Corbyn.
The committee's strongly-worded report was agreed in full by the two Labour MPs on the panel - Chuka Umunna and David Winnick.
A third Labour member of the committee, Naz Shah, took no part in the inquiry after she was suspended from the party over anti-Semitic social media posts. She later had the whip reinstated after apologising.
The report also criticised Liberal Democrat leader Tim Farron over his handling of allegations within his own party, particularly involving former MP David Ward.
"We were disappointed by the manner in which their Leader, Tim Farron, referred to disciplinary processes rather than explicitly condemning anti-Semitic remarks made by members of his party, and we were surprised to learn that Cllr David Ward remains an elected representative of the Liberal Democrats, despite his repeated anti-Semitic comments," the report said.
Sir Mick Davis, chairman of the Jewish Leadership Council, praised a "serious" report with "serious" recommendations.
He said: "The proposal of a working definition for anti-Semitism is a welcome start and their proposals to address the intolerable rise in hate speech online are timely and necessary.
"The report correctly says that it is not anti-Semitic to criticise or campaign against the actions of the Israeli government but it should be noted that disproportionate criticism of the Israeli government is problematic."