NICARAGUANS are dishonest alcoholics, the people of Thailand are sex-crazed philistines and Canada is thin on talent, according to confidential dispatches sent by some of Britain’s most eminent ambassadors.

The distinctly undiplomatic remarks have been gleaned from the valedictory letters traditionally sent by Foreign Office mandarins on retirement or as they leave an overseas posting.

Marked “confidential” or “restricted”, the missives were meant to provide an honest insight for the foreign secretary of the day and other senior civil servants.

Although some of the letters are witty, others verge on racism and risk causing offence.

Roger Pinsent, our man in Managua, did not mince his words on his departure from Nicaragua in 1967. “There is, I fear, no question that the average Nicaraguan is one of the most dishonest, unreliable, violent and alcoholic of the Latin Americans,” he wrote.

“The approaches to the towns are squalid to a degree that shocks the visitor from Europe. On arrival we unwittingly caused some offence by inquiring the name of the first village we passed through. It turned out to be the capital city, Managua.”

The Thais came out poorly too, in the eyes of Sir Anthony Rumbold, who served in Bangkok from 1965-67.

“They have no literature, no painting and only a very odd kind of music; their sculpture, ceramics and dancing are borrowed from others, and their architecture is monotonous and interior decoration hideous,” he recalled.

“Nobody can deny that gambling and golf are the chief pleasures of the rich, and that licentiousness is the main pleasure of them all.”

Even our Commonwealth neighbours take a hit. Lord Moran, who ended a 39-year diplomatic career in 1984 as high commissioner to Ottawa, summed up Canada with a dismissive tone.

“One does not encounter here the ferocious competition of talent that takes place in the United Kingdom,” he wrote.

“Anyone who is even moderately good at what they do — in literature, the theatre, skiing or whatever — tends to become a national figure. And anyone who stands out at all from the crowd tends to be praised to the skies and given the Order of Canada at once.”

Sir David Hunt, the high commissioner to Nigeria, claimed in 1969 that the country’s inhabitants had “a maddening habit of always choosing the course of action which will do the maximum damage to their own interests”.

He continued: “They are also not singular in this. Africans as a whole are not only not averse to cutting off their nose to spite their face; they regard such an operation as a triumph of cosmetic surgery.”

After his retirement, Hunt went on to win the BBC Mastermind title in 1977 and its Champion of Champions tournament five years later.

The letters have been unearthed by BBC Radio 4 using Freedom of Information rules and at the National Archives. They will be broadcast in a new series, Parting Shots, which starts on Tuesday morning.

The centuries-old tradition of allowing diplomats to speak their mind ended abruptly three years ago when the final letter of Sir Ivor Roberts, our man in Rome, was leaked to the press.

Roberts described a Foreign Office under siege from management consultants, efficiency drives and Wall Street business-speak mumbo jumbo.

Sir David Gore-Booth, the son of a diplomat, also cocked a snook at the Foreign Office when he left India in 1998. “One of the great failures of the diplomatic service has been its inability to cast off its image as bowler-hatted, pin-striped and chinless with a fondness for champagne,” he wrote.

Lord Patten, the last governor of Hong Kong, said ending valedictory letters showed “excessive sensitivity by the civil service”. Patten added: “They should have welcomed the chance of having a real discussion over whether they were actually losing something vital by insisting that ambassadors now spend most of their time ticking management consultant boxes.”

Sir Christopher Meyer, who served as ambassador to Washington in 1997-2003, made public many of his own views by publishing his memoirs. “It is not an ambassador’s job to tell people what they want to hear,” he said. “On the contrary, it’s to tell the truth as they see it.”

Times Recommends

• Foxy Knoxy snared by her lust and her lies
• Britain is the land of the shrinking family
• Zac Goldsmith: Not such a green god