The Foreign Office has refused to release a valedictory despatch written by a British ambassador to Israel almost 30 years ago over fears that it could damage current relations between the two countries.
The document was sent to London by John Robinson as he left Tel Aviv in 1981, just a year after he had arrived.
Mr Robinson died in 1998, but the Foreign Office has declined to release his despatch after a JC Freedom of Information request, saying it is still too sensitive to disclose because it "would be likely to prejudice relations" between the UK and Israel.
All departing British ambassadors traditionally send a final telegram home summing up their service, outlining their true feelings, often in more undiplomatic language than they might usually employ.
Mr Robinson's short spell in the Jewish state was littered with public spats with Israeli leaders, failures to strike up working relationships, and a widespread belief that he held anti-Israel views.
The remarks that he sent back to London on June 30, 1981, may never be known. The Foreign Office said: "A review of John Robinson's valedictory despatch has deemed that it remains sensitive. The FCO fully accepts that sensitivity can diminish with the passage of time. We have concluded that the exemption remains valid.
"In this instance we judge that not releasing this particular material into the public domain and maintaining our relations with the country concerned serves the public interest better."
When Mr Robinson took over in March 1980 his appointment was
initially viewed positively.
He was 55 and had spent decades working at British embassies in Finland, India, France, the United States. He was also ambassador to Algeria.
Previewing his arrival, the JC predicted: "Mr Robinson personally should go down well with the Israelis. He is far removed from the conventional stuffed-shirt diplomat. He is not an Arabist."
But in April 1981, Mr Robinson requested that his retirement be brought forward and asked to leave Israel.
British and Israeli press speculated that it was because "he was out of sympathy with Israel's policies".
The story made front page news, with the JC commenting: "He is far from being the most popular member of the diplomatic corps and, unlike previous British ambassadors, has appeared unable to strike up a friendly working relationship with Israeli ministers."
Mr Robinson had "isolated himself almost completely from Israeli policy-makers. He has also been involved in one or two public tiffs, when he made statements construed as lecturing Israel on how she should behave."
The existence of Mr Robinson's despatch emerged as journalist and former MP Matthew Parris and BBC radio journalist Andrew Bryson collated other ambassadors' documents for a book,
Parting Shots: The Undiplomatic Final Words of Our Departing Ambassadors.