British prime minister Margaret Thatcher secretly approved offering concessions to IRA prisoners if their hunger strikes were called off, files released after 30 years revealed Friday.

In public, Thatcher took a firm stance against demands to be recognised as political prisoners made by jailed Irish Republican Army members and other paramilitaries waging an armed campaign to end British rule in Northern Ireland.

Though largely backed in mainland Britain, her unbending stand triggered international condemnation.

However, files from 1981 released by the National Archives showed that her Conservative government sent messages to the IRA leadership, through a secret intermediary, promising concessions if the hunger strikes were stopped.

The papers reveal the anxiety among government ministers, despite their outward show of determination.

By July 1981, the pressure on Thatcher was intense over the issue. Four men had died, including their leader, 27-year-old Bobby Sands, who had been elected to parliament while on hunger strike.

So when the remaining hunger strikers dropped their demand to be treated as "prisoners of war", Thatcher authorised a secret message setting out what concessions the government would make if the strikes were called off.

The go-between was a Northern Irish businessman codenamed "Soon" who had contacts with an officer in Britain's MI6 foreign intelligence spy agency.

The files log a series of frantic calls between Soon and the MI6 man in the days leading up to the offer.

London set out the concessions the government was to offer "if, but only if, it would lead to the immediate end of the hunger strike".

They included allowing the prisoners to wear their own clothes, rather than prison uniform, and to receive normal visits, parcels and letters as well as "further developments" on prison work and remission.

The draft message in the files contains detailed amendments in Thatcher's handwriting, showing she was in on the secret plan.

The message ended: "If the reply we receive is unsatisfactory and there is subsequently any public reference to this exchange we shall deny that it took place. Silence will be taken as an unsatisfactory reply."

The approach was rebuffed and a fifth hunger striker died the following day.

Northern Ireland secretary Humphrey Atkins informed Thatcher: "Following the sending of the message which you approved last night, we have received, as you will know, an unsatisfactory response. That particular channel of activity is therefore now no longer active."

The government made a second attempt to break the deadlock which got nowhere.

The hunger strikes were to carry on for another three months, during which five more prisoners died.

On July 2, 1981, Thatcher told her Cabinet they should consider "all possible courses of action in regard to Northern Ireland, however difficult or unpalatable".

With "increasingly disturbing signs of an erosion of international confidence in British policy", ministers even discussed abandoning Northern Ireland -- hitherto unthinkable for a Conservative government.

But while there was "a widespread feeling in favour of British withdrawal" among the public, they admitted pulling out would not be an "easy proposition" with "civil war and massive bloodshed" likely to be the immediate outcome, the minutes noted.

The meeting also discussed intravenously force feeding the hunger strikers, although ministers again acknowledged there would be difficulties, including the possibility of all protesting prisoners going on hunger strike.