British government fury at the decision of then US president Bill Clinton to allow former Sinn Féin leader Gerry Adams into America have been laid bare in newly released official files.

Mr Adams was controversially granted a headline-grabbing visit to New York to speak at a conference on Northern Ireland between 31 January and 2 February 1994.

A blistering note from then prime minister John Major's private secretary Roderic Lyne sent to US national security adviser Tony Lake is part of around 500 Cabinet Office files released by the British National Archives in Kew, west London.

It reads: "The movement in which Gerry Adams has long been a leading figure has murdered not only thousands of its own countrymen, but also one member of our Royal Family, one Cabinet Minister's wife, two close advisers to Margaret Thatcher and Members of Parliament, two British ambassadors - and small children in our shopping centres."

Mr Clinton, who had been president for around a year, took "full responsibility" for the decision, which was described as a "difficult matter of judgment" in another file.

Mr Major wrote to Mr Clinton expressing dismay before the visit, according to a draft letter, he said: "Tony Lake will, I am sure, have told you how strongly we disagree with the decision to admit Gerry Adams to the United States.

"He has been closely associated with terrorism for two decades. In the Joint Declaration, he was offered a route into the democratic process, and into negotiations with us and with the Irish Government. He and his movement have not taken it.

"As you will know the evidence is that the IRA intend to continue their strategy of terrorism, and do not have courage to make peace and compete in the democratic arena."

Mr Clinton was under pressure from influential Irish-American politicians in the US, most notably senator Edward "Ted" Kennedy, who was named in multiple files as instrumental in pushing for Mr Adams's admission.

In a letter to the president in January, senators Kennedy, John Kerry, who was later Barack Obama's secretary of state, Daniel Patrick Moynihan and Christopher J Dodd, make the case for the visit.

The letter said: "While no one can be certain that a visa for Mr Adams will result in the IRA's accepting the condition established by Ireland and Great Britain for participation in the peace process, the United States cannot afford to ignore this possibility and miss this rare opportunity for our country to contribute to peace in Northern Ireland."

The note from Mr Lyne to Mr Lake added: "It is sad, paradoxical, and misguided of the Kennedys, having lost two brothers to acts of terror, to be pressing you to admit a terrorist leader without an end to terrorism or even a commitment to end terrorism."

A cable dated 10 February from Peter Westmacott, then a British diplomat in Washington, adds details garnered from Jane Holl, then of the US National Security Council, who had been present during a subsequent phone call between Mr Major and Mr Clinton.

It reads: "Dr Holl said that the discussion on Northern Ireland was very brief. The President had raised the subject. He had taken full responsibility for the decision to give Adams a visa.

"It had been a difficult matter of judgment on which the two governments had evidently differed."

Also attached to the bundle was a missive from Canberra suggesting that a potential visit by Mr Adams to Australia may go ahead in light of the US decision.

Mr Lyne has scrawled on the typed document: "I hope the Aussies realise this would be the end of Anglo/Australian relations!"

Mr Adams was denied entry to Australia in 1996, but later visited in 1999 following the Good Friday Agreement a year earlier.