EVEN the Iron Lady needed a warning not to trust then-Taoiseach Charles Haughey before their first meeting.
British Ambassador to Ireland Robin Haydon described Mr Haughey as a " tough, clever, wily man" who was "conscious of his shady past (and present!)".
The shocking and candid observations about the then-Taoiseach were revealed yesterday when top-secret British diplomatic dispatches were declassified.
The comments on Mr Haughey were made in cables from Mr Haydon in Dublin to the then-British Prime Minister Margaret Thatcher.
The ambassador sent his dispatches directly to 10 Downing Street ahead of Mr Haughey's first face-to-face meeting there with Mrs Thatcher in May 1980.
However, Mr Haydon's judgment of Mr Haughey was neither nuanced nor qualified, but a double-barrelled blast of insults and disapproval.
Mr Haydon warned his prime minister that Mr Haughey was a man of "calculating and ruthless ambition" who had a "taste for the good things in life", but few real friends.
The character sketch of Mr Haughey would have caused a serious diplomatic problem if it had been discovered by the Irish government at the time.
Mr Haydon wrote: "His predominant characteristic seems to be a ruthless ambition: there is no secret that the office of the Taoiseach has been the over-riding ambition of his life."
He added: "He seems to have few real friends but appears to surround himself with a close-knit and faithful coterie of associates whom he dominates by force of character."
Mr Haydon then described Mr Haughey as a former heavy drinker who had become a "puritan" and had all but given up alcohol and tobacco.
The ambassador said that Mr Haughey's lavish lifestyle was partly funded by property speculation when he was Finance Minister in the late 1960s.
Describing Mr Haughey's extravagant spending, the ambassador noted that he collected pictures and antique furniture, owned racehorses and enjoyed riding to hounds.
He described Mr Haughey's period home in Kinsealy as a "showplace" house and said the Taoiseach was "immaculately turned out".
"To sum up," wrote Mr Haydon, "I think he is a tough, clever, wily man, no friend of ours, but not, perhaps, actively hostile. He is conscious of his shady past (and present!)."
But despite the ambassador's warnings, both Mr Haughey and Mrs Thatcher agreed that their meeting in London in May 1980 was a great success.
Mr Haughey told Mr Haydon that he was "most impressed" by Mrs Thatcher and the atmosphere at their lunch in 10 Downing Street was "wonderful".
But the diplomatic file also contains Mr Haughey's reply when Mr Haydon asked him about the concerns of Protestants in Northern Ireland.
Mr Haughey said he was "not a deeply religious man and did not mind if someone wanted to worship Ali Baba and the Seven (sic) Thieves".
Diplomats who knew Mr Haydon said his dislike of Mr Haughey may be based on the circumstances of him being appointed to Dublin.
His immediate predecessor Christopher Ewart-Biggs was murdered by a roadside bomb near his residence in Dublin and several attempts were made on Mr Haydon's life.
Mr Haydon was knighted after serving in Dublin and died aged 79 in December 1999; Mr Haughey served as Taoiseach on three occasions and died in June 2006 aged 80.