Colonel Muammar Gaddafi urged the head of the United Nations to intervene and stop the IRA hunger strikes.
Comparing the deaths to ancient sacrifices and accusing Britain of lacking humanity, the Libyan dictator warned of a painful fallout if the prisoners were not granted political status.
Gaddafi said the hunger strikes were a "very painful human tragedy, a tragedy that should have shocked the conscience of the entire world".
"It appears that the world in which we live has lost its conscience," he said.
In the letter, addressed to Dr Kurt Waldheim, UN Secretary-General in 1981, Gaddafi said the prisoners' deaths were courageous.
"These men should be granted a political status in view of the fact that they are indeed fighting for a just and sacred cause, the freedom of their nation, which is one of the world's smallest, but which still has its place under the sun, free as God created it."
At the time, British authorities urged the UN not to circulate the letter. Irish civil servants in the UN and the political and Anglo-Irish sections of the Taoiseach's office insisted there should be no reply.