Thatcher paved the way for peace in Northern Ireland

Although few view Margaret Thatcher as one of the architects of the peace process which has brought much progress and relative peace to Northern Ireland, she played a hugely important part in its development.

She herself, and the world in general, viewed her approach as being dominated by security considerations rather than political calculation. That approach was, in the words of her aide Charles Powell, one of "security first, second and third."

But that did not prevent her approving of clandestine contacts with the IRA, even after republicans assassinated two of her closest associates, MPs Airey Neave and Ian Gow, and tried to kill her by bombing the Grand Hotel in Brighton in 1984.

Nor did it prevent her signing a historic deal with the Irish government a year later. She saw that accord, the Anglo-Irish Agreement of 1985, principally as an instrument for strengthening security.

But it also established a new context in which the Northern Ireland problem ceased to be regarded as an internal matter for Britain, and instead became an issue to be addressed by a new London-Dublin partnership.

This framework brought together two governments which had previously often seemed in competition. The relationship from then on had many difficult moments but overall there was agreement on a common goal, that of putting peace first and together making a stand against the IRA.

Her 1985 accord had a profound effect on the thought processes of the IRA, which until that point had asserted its violence was a classic anti-imperialist and anti-colonial campaign.

This stance became much more difficult to maintain when Thatcher, despite her famous emphasis on national sovereignty, agreed to give another government a formal role in Northern Ireland matters. She did so with many reservations, and afterwards wondered if she had done the right thing; but she did it.

Her emphasis on security was understandable, given that republicans killed 500 British soldiers during the conflict in their long-running but futile efforts to force Britain out of Northern Ireland.

The organisation operated not only in Belfast but also staged many attacks, and killed many people, in England. After her refusal to make concessions to protesting republicans during the 1981 hunger strike she became Irish republicanism's hate figure.

The Brighton bomb was designed as an act of personal revenge against her. It almost succeeded, for the explosion killed five people, some of whom died close to her room.

She recalled being led from the ruined building with the sensation of having cement, dust and grit in her teeth. Haunted by the idea of being left in the dark in the event of another attack, for months afterwards she kept a torch by her bedside when staying in a strange house.

The IRA reflected the personal element in the bombing when in a chilling statement it warned her: "Today we were unlucky but remember we only have to be lucky once. You will have to be lucky always."

She and many others initially regarded her stance during the hunger strike as a major defeat for the IRA. It was certainly not a victory for the strikers themselves: ten of them died.

But it turned out to deliver a highly significant advance for the republican movement, since a wave of sentiment against her allegedly inflexible position provided a rich political electoral harvest for Sinn Fein, the IRA's political wing.

She herself, who had denounced the hungerstrikers as convicted criminals, would later say that it was possible "to admire [their] courage… but not to sympathise with their murderous cause."

The Sinn Fein vote surged so dramatically that it alarmed Irish prime minister Garret FitzGerald, who feared violent republicanism "could get out of control, threaten the whole island… and attempt to destabilise the Republic."

Such anxieties were shared by senior British officials, principally cabinet secretary Robert Armstrong, who along with FitzGerald eventually persuaded her that a political initiative was urgently needed to stem the rise of Sinn Fein.

She never envisaged that the peace process would eventually lead to today's inclusive settlement in Belfast, which has put Martin McGuinness of Sinn Fein into government. But before leaving office in 1990, when MI5 reported to her that the IRA might be led to abandon the killings, she gave the go-ahead for extensive contacts with its leaders.

Her new Anglo-Irish approach led to highly productive relationships between subsequent prime minsters, John Major working closely with Albert Reynolds and, in particular, Tony Blair linking up with Bertie Ahern.

These partnerships eventually led to ceasefires by the IRA and other violent groupings, and in time to the IRA's departure from the scene.

The road to peace was long and tortuous, with some of Margaret Thatcher's actions producing utterly unintended consequences. But the Thatcher-FitzGerald accord of 1985 set new parameters which made many unprecedented things possible.