By Dominic Casciani BBC News Online at the National Archives

Henry Kissinger was Richard Nixon's right-hand man

In confidential conversations with the British ambassador, the controversial politician attacked the Nixon team he was working for.

Mr Kissinger said he had disliked President Kennedy's people - but Nixon's were far worse.

And despite what people thought, Mr Nixon was actually a "good warm-hearted man", said the statesman.

According to papers released at the National Archives, Britain's ambassador to the United States held in-depth off-the-record discussions with Mr Kissinger during 1970.

These were designed to allow both men to get a better understanding of each other's foreign policy and to strengthen the ties between London and Washington.

In the case of London, every detail of the talks was relayed to Ambassador John Freeman's boss at the foreign office, Sir Denis Greenhill. Henry Kissinger apparently reported back to President Nixon.

I used to find the Kennedy group unattractively narcissistic, but they were idealists - these people are real heels Henry Kissinger on President Nixon's team

Over time, the two men built up a warm relationship with Mr Freeman describing Mr Kissinger as often relaxed, good humoured and increasingly happy to talk candidly about White House life.

In one conversation, Mr Freeman felt in the confidence of Mr Kissinger to ask him for personal views on the president.

"The president, said Kissinger, was not an easy man to read even by those who knew him well," reported the ambassador.

"For years he had represented in Kissinger's eyes all that was most objectionable in political life.

But he had now changed his mind and the president was, in fact, a good, warm-hearted man.

Mr Freeman said Mr Kissinger's main criticism of the President "was directed against those who surrounded him".

"He said: 'I have never met such a gang of self-seeking bastards in my life'.

"When I observed that the same criticism had been levelled at other national leaders and that perhaps this sort of thing was always said, he replied: 'No, I used to find the Kennedy group unattractively narcissistic, but they were idealists. These people are real heels.'

"I find this convincing testimony, and Kissinger is not the only inside-man to think like this," concluded the ambassador.

Call from Nixon

Mr Kissinger appeared to get on so well with the British ambassador that he used this informal channel to smooth over relations between the White House and London.

In one incident, President Richard Nixon had taken offence to the "patronising" tone of then Foreign Secretary Michael Stewart. Ambassador Freeman listened carefully and later recommended that London should more carefully prepare for future presidential meetings.

But some hours after the conversation, the ambassador received a call out of the blue from the President himself. Mr Kissinger could also be heard in the same room.

Mr Kissinger had related the conversation to the president - and Mr Nixon felt he needed to call immediately to stress no harm had been done to Anglo-American relations.

"I am completely unable to interpret this incident which astonished me," said the ambassador. "It does appear to illustrate that there is an extraordinarily close link between Kissinger and the President."