FitzGerald accused Thatcher of failing to deliver on Agreement
The Irish Government accused Britain of failing to deliver on the Anglo-Irish Agreement in angry exchanges between the two countries.
Taoiseach Garret FitzGerald said more visible progress was urgently needed, prompting British Prime Minister Margaret Thatcher to question his attitude.
His warning is contained in a briefing sent to Mrs Thatcher in June 1986.
It came seven months after the signing of the historic Agreement, which granted the Republic a formal role in Northern Ireland for the first time since partition.
The note, marked "secret and personal", is an account of a meeting between Cabinet secretary Sir Robert Armstrong and Mr FitzGerald.
Mr Armstrong describes how he was called aside by the Taoiseach ahead of a meeting.
"The Taoiseach said that he thought the Irish Government could reasonably claim to have delivered on their side of the Anglo-Irish Agreement," he wrote.
The letter, released this week by the Northern Ireland Public Record Office, adds: "The Taoiseach was, however, worried about our side of the affair.
"Unless it was possible to make more visible progress, he feared that he would find it difficult to sustain his position that the Anglo-Irish Agreement had been a move forward entered into in good faith by both sides."
Mr FitzGerald expressed unease that the Irish Government had been requested to assist with the Anglo-US supplementary extradition treaty. The treaty effectively meant that ex-IRA members in the US were not protected from extradition.
Mr Armstrong's memo added: "[The Taoiseach] had thought that the British Government had understood the Irish Government's difficulties on this, and the request had been an unnecessary aggravation."
In an attached briefing note, Mr Armstrong advises Mrs Thatcher that Mr FitzGerald "might be having trouble with some of his 'greener' colleagues in Government, who see the Anglo-Irish Agreement as very much his responsibility and measure his success by the degree of progress in its implementation."
When the paper reached Downing Street, Mrs Thatcher was far from impressed. A response from her private secretary Charles Powell said she was "concerned by his attitude".
He wrote: "It seems to the Prime Minister that the Taoiseach quite fails to realise the difference in scale between the political problems facing our government and his over the Agreement."
She also described Mr FitzGerald's comments on extradition as "astonishing".
It added: "[She] resents suggestions that lack of progress with implementing the Agreement can be put down to the United Kingdom's account.
"She intends to make these points to the Taoiseach when they meet."