Cabinet papers released today under the ‘30 year rule’ reveal that Baroness Thatcher warned one of her ministers that a speech he planned to deliver in Israel would “end his promising career” if he went ahead with it.

William Waldegrave — made a peer in 1999 — was a junior minister in the Foreign and Commonwealth Office on a visit to Israel in February 1989 when a copy of the speech he planned to give to the Israeli Council for Foreign Relations landed on the Prime Minister’s desk.

Responding in characteristically forthright terms in a handwritten note — using capitals for emphasis — Mrs Thatcher wrote: “NO. This is Not the speech of a MINISTER but that of a BRILLIANTLY CLEVER commentator with NO RESPONSIBILITY for EVENTS. HE CANNOT MAKE IT. IT would END his promising career.”

She concluded: “I need William for the future. A dull but understanding speech is his best solution”.

In a cover note, Charles Powell, Mrs Thatcher’s private secretary, warned her that Lord Waldegrave had “decided to write it himself rather than get officials to do it for him” and was “now engaged in a tussle with the Foreign Office over it”.

In tones reminiscent of Yes Minister’s Sir Humphrey, Mr Powell added: “I think it is a remarkable speech. If I have any criticism, it is that the speech is too clever.”

He believed two passages in particular were likely to land Waldegrave “in trouble”.

One passage in the draft speech speculated on the possibility of Israel launching a pre-emptive nuclear strike against its neighbours were it ever threatened, while another referred to Israeli use of “age old methods of Imperial intimidation and terror on a rebellious subject people” in the West Bank.

Relaying Mrs Thatcher’s concerns, Mr Powell told Lord Waldegrave his words were likely to be taken out of context and “quoted as an example of your predilection for Israel-bashing”.

He went on: “I hate to be arguing for banality. No doubt many of these things need to be said. But not publicly, not by you, and not just now.”

In the end, an almost unrecognisable version of the speech was delivered by Lord Waldegrave on March 5, 1989, and according to Mark Elliott, the British Ambassador to Israel, it was “well received by those present as a balanced and highly intelligent presentation of the British position.”

Both versions of the speech are now available at the National Archives in Kew, west London.