The poison of anti-Semitism "sanctioned from the top" has taken root in Britain's opposition Labour Party, Chief Rabbi Ephraim Mirvis said in an article published on Monday, warning the "soul of our nation is at stake" in next month's election.

Labour leader Jeremy Corbyn, a veteran campaigner for Palestinian rights, has been dogged by criticism from members, lawmakers and Jewish leaders that he has failed to tackle anti-Semitism in the party despite a promise to do so.

"The question I am now most frequently asked is: What will become of Jews and Judaism in Britain if the Labour Party forms the next government? This anxiety is justified," Mirvis, Chief Rabbi of the United Hebrew Congregations of the Commonwealth, wrote in an article for Tuesday's edition of the Times newspaper.