Former Taoiseach Garret FitzGerald personally pleaded with US President Ronald Reagan to pile pressure on Margaret Thatcher for an urgent compromise over the Maze hunger strikes.
In a desperate sign of the gravity of the crisis, Dr FitzGerald -- who had taken office only days beforehand -- warned that Ireland's democracy was seriously under threat while relations with Britain were plunging to dangerous depths.
And he also warned Mrs Thatcher that Ireland could be forced to cut off security ties with the British.
He told the British prime minister his government's view of her handling of the crisis was starting to resemble the IRA's.
"This is naturally the last position in which we would wish to find ourselves," he said in a secret letter, declassified under the the 30-year-rule.
But in a signal of the diminishing relations, Mrs Thatcher threatened a "sharp and bitter" response if there was any suggestion of less than full co-operation in the fight against the IRA. Mr FitzGerald explained his newly elected coalition was unable to do or say anything to counter the lack of public confidence in the British government's handling of the crisis.
"We are thus faced with the danger of a serious and progressive deterioration in bilateral relations," he said.
In a veiled threat to pull security ties with the British, Mr FitzGerald said co-operation depended on public backing.
"As both governments know, the effectiveness of security measures depends on the prevailing climate of local opinion," he wrote.
Days later hunger striker Martin Hurson died before Mrs Thatcher replied on July 15 with her own stark warnings.
"I cannot believe your government will wish in any way to diminish the scale or intensity of the (security) co-operation," she wrote.
"The reaction of public opinion here (in Britain) to any suggestion that the authorities in the Republic were offering less than full co-operation in the detection and apprehension of terrorists would be sharp and bitter.
"There must be a risk that it would have an adverse effect on wider Anglo-Irish relationships." In a parallel attempt to win support from the US leader, Dr FitzGerald assured Mr Reagan that he could play a decisive role in ending the hunger strike.
In the letter, dated July 1981, Dr FitzGerald said it was his duty to seek the co-operation of "the leader of the greatest democracy on earth".
"I would ask you to use your enormous influence with the British prime minister within the next 24 hours in the interest of averting a death which would inevitably increase support for the terrorists," he wrote.