A veteran British MP quit the main opposition Labour Party group in parliament on Thursday over mounting anti-Semitism allegations that have dogged Jeremy Corbyn's leadership.

Frank Field, who has sat in the House of Commons for almost 40 years, said in a letter to the party that Corbyn's leadership was overseeing an "erosion of our core values".

"I am resigning the whip for two principal reasons," he explained.

"The first centres on the latest example of Labour's leadership becoming a force for anti-Semitism in British politics.

"Britain fought the Second World War to banish these views from our politics, but that superhuman effort and success is now under huge and sustained internal attack.

"The leadership is doing nothing substantive to address this erosion of our core values," he added.

He also accused some members of his local Labour Party branch of "thuggish conduct", which had gone unpunished.

Field vowed to retain his party membership, but in resigning the whip will no longer sit as a Labour MP bound by the instructions of the parliamentary party or receive its benefits.

He plans to remain in parliament as an independent MP, and said he plans to stand at the next general election.

Labour won 262 seats in the 2017 general election but are currently down to 257 after the suspension of two MPs pending sexual harassment allegations, while John Woodcock, Jared O'Mara and now Field have quit the party whip in recent months.

Field came under fire after defying the party's leadership and voting with the government on key Brexit legislation.

Corbyn has conceded that his party has a "real problem" with anti-Semitism in a recent newspaper article.

But Britain's former chief rabbi Jonathan Sacks this week directly called Corbyn an anti-Semite who "supported racists, terrorists, and dealers of hate".

His intervention came after the rediscovery of a 2013 speech, in which the veteran leftist Corbyn said British "Zionists... don't want to study history" and "don't understand English irony" despite having lived there "for a very long time, probably all of their lives".