Although it was never officially admitted, gardai did detect suspicious activity and arrested a number of suspected IRA men in Monaghan on the morning the IRA bombed the Remembrance Day ceremony in Enniskillen.

Three Co Tyrone men on the run from the RUC and living in Monaghan were stopped in a car in Monaghan hours before the explosion.

The woman believed to be the leader of the South Fermanagh Brigade of the IRA was also understood to have arrived in Monaghan that morning. Gardai regarded the activity as suspicious but thought little more of it until later in the morning when the reports of the Enniskillen bombing arrived.

The men detained in the car and a number of others were questioned and forensic tests taken but no evidence of any kind was found to connect them with the bombing, according to officers.

However, intelligence reports later indicated that it was almost certain that the eight IRA suspects whose movements were detected in Monaghan that morning were involved in the bombing.

Gardai and RUC believe the bombing operation was led by the woman, and that she was in the group that had driven west from Enniskillen after they had finished planting the bomb in the building owned by the Catholic Church beside the Cenotaph at around 10.43 a.m. on Remembrance Sunday.

The woman, although still only in her 20s, was known as an extremely hard-line figure who had risen rapidly through the local IRA ranks. She was said by officers to have engaged in the torture of at least one IRA man suspected of passing information to gardai in Monaghan.

Importantly, she and the man believed to have been her co-leader of the bombing operation were close to the IRA's chief-of-staff, a Co Tyrone man living in a north Monaghan village.

Intelligence appraisals of the Remembrance Sunday bombing put it in the context of a decadeand-a-half of assassinations of Protestant security forces members along the Border by the IRA's Border brigades. In the late 1980s IRA tactics had grown to include coordinated "spectaculars", such as double or treble bomb attacks in different locations.

At the same time as the Enniskillen bomb was detonated, the west Fermanagh IRA was unsuccessfully trying to detonate at second 400 lb landmine at the site of the Remembrance Day ceremony in the village of Tullyhomond, just across the Border from Pettigo in Co Donegal. This event was attended by more than 100 members of the Boys and Girls Brigade, the Protestant equivalents of the Catholic scouts and girl guides.

If this bomb had exploded it would have caused even worse carnage than the one at Enniskillen. Forensic examination of the device showed that it was wrongly wired. It was never ascertained if this was done intentionally or accidentally by the west Fermanagh bombers, who must have been aware of the likely outcome of their bomb.

The Tullyhomond bomb was connected to a command wire running across the Border into Donegal. However, the Enniskillen bomb was detonated by a timer. This meant that the Enniskillen bombers knew they would have no sight of the likely target and could only surmise what the impact of the bomb would be.

A report in The Irish Times about a week after the Enniskillen bombing, that the device was detonated by a timer, was denied privately to other journalists by a senior Sinn Fein figure who acted as an unofficial IRA source to the media. However, British army ordnance officers were able to reconstruct part of the timer, a device commonly used in IRA bombs.

In its only official comment about the bombing, the IRA said it had been a "mistake". However, the organisation badly misjudged both the scale of the likely carnage and the international impact.

The event drew international opprobrium down on the IRA and the visit to the injured by Diana, Princess of Wales, and Prince Charles drew international media attention to the event. Privately, republican sources admitted that it had virtually reversed the positive international image the organisation had built up at the time of the hungerstrikes.

The Sinn Fein president, Mr Gerry Adams, made the first of a series of apologies for IRA actions and within two years was promoting his "unarmed strategy" policy and secretly opening contacts with the then Fianna Fail government about building a peace process.

Despite setbacks, Mr Adams's policy has largely proved successful. The former chief-of-staff who allowed the Enniskillen bomb recently resigned from the IRA in protest at the peace process. The woman who led the bombing team is in the US, where it is understood she is raising a young family.