LONDON — The archbishop of Canterbury has said an unusual electoral intervention by Britain’s chief rabbi should alert the country to the unease felt by many Jews.

Justin Welby tweeted Tuesday after Chief Rabbi Ephraim Mirvis wrote in The Times of London that Britain’s Labour Party and its leader Jeremy Corbyn have been deeply tarnished by anti-Semitism.

Welby said political parties must make it “an absolute priority” to avoid any actions that increase the perception of fear. He said Mirvis’s statement “ought to alert us to the deep sense of insecurity and fear felt by many British Jews.”

It is very rare for the chief rabbi to express his thoughts on party politics during an election campaign. He stopped short of advising voters to shun Labour but made his feelings clear.

“The way in which the (Labour) leadership has dealt with anti-Jewish racism is incompatible with the British values of which we are so proud,” he wrote.

“It is not my place to tell any person how they should vote. … I simply pose the question: What will the result of this election say about the moral compass of our country?”

The Labour Party under Corbyn has been repeatedly accused of reacting too slowly when members make anti-Semitic comments. Earlier, the influential Jewish Chronicle newspaper had warned about the dangers of Corbyn becoming prime minister.

Corbyn, a champion of Palestinian rights and frequent critic of the Israeli government, denies his party is anti-Semitic and says he denounces all forms of racism. The election is set for Dec. 12 with all 650 seats in the House of Commons up for grabs.

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