The threat of extremists sending cells to the UK capital was also causing concern, according to the confidential records which were released yesterday.

The armed struggle against the British Mandate of Palestine had seen the murder in Cairo in late 1944 of Britain’s minister resident in the Middle East, Lord Moyne, by members of the extremist Stern Gang.

Fellow Jewish resistance movement Irgun – which came to be headed by future Israeli premier Menachem Begin – had also conducted a violent campaign against British rule.

This included the July 1946 bombing of the King David Hotel in Jerusalem, the site of the British military command and the British Criminal Investigation Division, and the bombing of the British Embassy in Rome the same year.

He added that the attempts consisted of 20 letterbombs to be posted to the government, but they had had to be posted from Italy as they couldn’t find people to post them in London. “But nonetheless, the belief was that there was a serious assassination plot,” he said.

The files contain a telegram dated February 12, 1946, from Palestine, which revealed a reliable source had told CID that the Stern Group “are training members to go to England to assassinate members of His Majesty’s Government”.

A memo the following day from the officer administering the government of Palestine to the secretary of state for the colonies then passed on further details of “alleged plans by the Stern Group to assassinate certain of His Majesty’s Ministers and other prominent personages in Britain”.

Further documents revealed how Begin was thought to have confounded the British security services by having cosmetic surgery to change his identity in the 1940s.

A note from February 1947 passed on reports to MI5 that he “has undergone a plastic facial operation and that his appearance is totally different from that displayed on police photographs”.

In 1948 Begin founded the Herut Party – which became the Likud Party – and became premier in 1977. A year later he was jointly awarded the Nobel Peace Prize after negotiating the Camp David accords with Egypt.

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