AN attempted assassination of Margaret Thatcher and her cabinet led to the near-total collapse of secret Northern Ireland peace negotiations, official documents have revealed.
The October 1984 Brighton bombing, orchestrated by the IRA, targeted the then government at the Grand Hotel during the Conservative Party conference in Brighton, killing five people and injuring 31.
Conservative MP Anthony Berry was killed in the attack, which was orchestrated by Patrick Magee, a 35-year-old IRA man from Belfast who served 14 years in prison for the crime.
In a previously unknown consequence, the bomb jeopardised Mrs Thatcher's own work four months earlier when she sought and secured cabinet approval for a series of secret liaisons with the Republic.
The meetings were known within Downing Street as the "Armstrong/Nally talks", named after Robert Armstrong, then British Cabinet Secretary, and Dermot Nally, the then Secretary to the Irish Government.
Updating her government on their progress in June, before the Brighton bombing, Mrs Thatcher said: "If complete secrecy was not preserved, progress would be impossible.
"It was necessary at this juncture to look further ahead into Ireland than the British government had done before.
"Ten thousand British soldiers could not be left in Northern Ireland for ever, nor could the very considerable cost of subsidising the province be sustained, without continuing to search for possible forward movement."
The covert interactions were launched to find solutions to the Northern Ireland crisis that were agreeable to both countries, and have since been hailed as a crucial steering committee for the Anglo-Irish Agreement announced in November 1985.
But newly-released documents show Mrs Thatcher was reluctant to sanction their continuation after the Brighton bomb, saying she was "very pessimistic" about their outcome in November 1984.
The meetings were quickly successful in the months before the attack. By October, Mr Armstrong told the British government that he and Nally had found multiple "hypothetical" measures "on which both sides might agree".
In a briefing paper he drafted in the week before the bomb, he outlined a proposed joint security commission, mixed law courts and raised the idea of an Anglo-Irish parliament.
He wrote in addition: "Both sides agree that it would be desirable to introduce a system of devolved government into Northern Ireland."
Following a meeting days after the bomb, he told Number 10 that Taoiseach Garret FitzGerald wanted to agree to the basis of the Anglo-Irish Agreement by December – a full year before the announcement was actually made.
Private correspondence between Mrs Thatcher and her closest advisers show she deliberately tried to cool negotiations after the bomb.
She said Britain must avoid the impression of "being bombed into making concession to the Republic".
Charles Powell, one of Mrs Thatcher's closest advisers, told the Foreign and Commonwealth Office on October 19, 1984: "The Prime Minister commented that the terrorist bomb in Brighton has slowed these confidential talks down and may, if it turns out to be the first in a series, kill the initiative altogether."
He subsequently wrote to Mr Armstrong, directing him on how to negotiate with Mr Nally in an upcoming tete-a-tete.
He said: "The events of last Thursday night in Brighton have confirmed the Prime Minister in her view that we must go very slow on these talks and must at all costs avoid the impression of being bombed into making concessions.
"The Prime Minister does not at this stage wish you to discuss a possible communique for the Anglo-Irish summit with Irish officials. She wishes to reflect further on whether there should be a communique at all."