The chairman of antisemitism watchdog the Community Security Trust has said “the leadership of the Labour Party and its most vocal followers" are “the biggest political defence issue that our community has faced for decades.”

In an open letter, Gerald Ronson said: “I have never been party political and neither has CST, but our community now faces an extraordinary situation... This is the biggest political defence issue that our community has faced for decades.

“CST does not chase publicity for our work, but I want you to know that we are doing all we can to provide our Jewish community with the best possible protection.”

He also said that he understood “why some families are expressing fear for the future, but I assure you all that neither I, nor CST, are going anywhere. We are proud of the community that we have helped to build and protect. We are British. We are Jewish. That will not change under my watch.”

Mr Ronson’s comments came a day after a poll for the JC revealed that almost 40 percent of UK Jews would “seriously consider emigrating” if Jeremy Corbyn became Prime Minister.  

“In the 1950s and 1960s, the fascists had to be physically forced off our streets. That is what we did,” Mr Ronson said.

“In the 1970s and 1980s, we had to develop security against terrorists. That is what we did. In 1994, after the car bombings of the Israeli Embassy and Balfour House, CST was fully established.”

As detailed by the JC last month, Jeremy Corbyn, then a backbench MP, spent over a decade campaigning for the release of the two people convicted for their part in the 1994 car bombings, claiming there had been “a miscarriage of justice”.

Mr Ronson added: “CST has spent millions of pounds providing security for Jewish communities across the country.

"If you lead any sort of Jewish life, from school to synagogue to old age home, CST is helping to secure you and your family.

"I am proud of what we have built, and I thank the thousands of Jewish men and women who have helped make it a reality.”