One of the worst atrocities came when the IRA's 1987 Enniskillen bomb killed 11 civilians on Remembrance Sunday. Amid public revulsion, Gerry Adams said the attack undermined the "legitimate" use of physical force.

But the security forces were also hitting the IRA hard, killing an eight-strong unit who attacked a police station in 1987 and another trio on Gibraltar in 1988. These events triggered more violence - but they did not stop the republican movement's continuing political changes.

Its strategists increasingly wanted to politically engage opponents. Sinn Fein first attempted this with a 1987 paper setting out guarantees for unionists who accepted a united Ireland.

British officials dismissed the proposals as no more sophisticated than the IRA's 1972 London demands. But they did indicate that there was a seed of a debate within the movement over how republican ideology could accomodate the rights of unionists.