In an uncanny parallel of the Northern Ireland referendum campaign that immediately preceded this weekend's debate on Rule 21, these have been seven days when the Yes camp has finally woken up to the need to go public and forcefully argue the case in favour of deletion of the controversial rule from the GAA's offical rulebook.

In the period since the GAA president, Joe McDonagh, suggested the removal of the rule, which prohibits members of the British army and the RUC from joining the GAA, at the association's annual congress last April, it has been the strident No voices which have taken central stage. But now some of the human stories and the harsh realities behind the stark wording of the rule are starting to emerge, just as the GAA faces up to the crucial vote later today.

Sean McNulty chose this week to tell his story. Born in the heart of football country in the GAA stronghold of Co Down, his was an upbringing steeped in Gaelic football.

"I went to a Catholic school," he says, "and was brought up with football. I then moved into the Burren club sides at underage level, under 11, under 14, that sort of thing, and from there into the reserve and senior teams for my club. Then there was the all-Ireland."

The all-Ireland arrived on September 25th, 1977, when Sean played at right corner back on the Down side that beat Meath by eight points to win the all-Ireland minor football title. For an ambitious young footballer life doesn't get much better.

That team proved to be the launch pad for Down's sustained success at senior level in the 1990s, and among Sean's team mates that day were Paddy O'Rourke and Ambrose Rogers, who later won full all-Ireland honours with Down in 1991.

But by then Sean McNulty had been barred from playing Gaelic football or hurling for over nine years following his decision to join the RUC.

"I played my last game the week before I left home," he says. "We had just won promotion. But I was very clear about it. I knew what would happen. But that doesn't mean I haven't always regretted it."

Joining the RUC was a clear-cut career decision for McNulty, but the implications of exile from the GAA became clear only over time. "I never got the chance to play in that all-Ireland final in 1991. What a dream that would have been," he says. "Looking back, I don't think I was really prepared for the shock or for the gap it left when I joined the force. Nothing ever really replaced it."

Constable McNulty, as he then was, worked first in Derry, but any illusions he had that he could remain immersed in the GAA were soon dispelled. "I gave up a lot of good friends and left a lot of good people. I was in Derry for a long time, but there was no opportunity to go and watch a match because we were reminded all the time about our personal security."

Rule 21 was redrawn in 1985 at a special congress of the GAA to correct a perceived anomaly where members of the Royal Air Force were outside its scope and it remained a fixture of GAA life, with hardly a murmur of opposition, throughout some of the darkest days of the Troubles.

To large sections of the nationalist, and by extension the GAA, communities, the RUC remained an unacceptable force. But now that is being addressed by provisions within the Belfast Agreement, and Joe McDonagh has decided to grasp the GAA's most troublesome nettle.

It was Sean McNulty's home county, Down, that first mooted the prospect of change, and he feels the environment is now right for deletion. "Times are changing. I can now go and watch a match without any problems. It would be a good thing for the game if it goes and I hope it does go."

With all nine Ulster counties looking likely to oppose deletion, or even suspension of Rule 21, there would appear to be an implacable mood on the ground against any change to the status quo. But that unanimity ignores the dissenting voices that have been drowned out in the clamour to present a united Ulster front.

Sean McNulty is encouraged by the ripples of support for the removal of the prohibition on the security forces and looks to the future.

"I do think if this rule does eventually go there will be an RUC team. Already there are quite a few people phoning me saying, `Let's get a team together'. The army played a game at Ballykinlar a few years ago, and there's no reason why in time we couldn't play them. In time it will come."

The past history of the GAA suggests that even if change doesn't come today at Dublin's Burlington Hotel, some certainties and a few of the more entrenched positions will have been chipped away by a public airing of the issue. The ground may then have been laid for deletion of Rule 21 at a later date.

Sean McNulty, however, remains doggedly optimistic and hopes a return to the games he was forced to leave behind may not be too far away.

"For me it would be a chance to turn the clock back 16 years. I'm doing a lot of running now and the weight's coming off. They say once you've got it you never lose it. In time people will get used to the idea.

"It's just going to take a few of us with a lot of guts. We know that if we go back to play we're going to be the target for a lot of abuse on the pitch. But there's no reason now why we shouldn't be allowed to go back and play."

Footnote: Because of the continuing threat to his life, Sean McNulty felt unable to be photographed for this article