BY A strange coincidence, on the eve of the last Old Firm match of the season, more than one person last week asked: ''Where is the man who has played in more Glasgow derbies than anyone of the modern era?'' Well, the answer is Houston, Renfrewshire, where he is happily sitting tight raising a small army of children.

Paul McStay is now up to five offspring, and there's a sixth on the way. Prior to last week, the last time I had seen him was in November 1999 when the people-carrier he was navigating had children and streamers hanging from every window as it pulled into Hampden Park for the first of Scotland's Euro 2000 play-offs against England. ''It's virtually a full-time job being a father,'' he says with a smile. ''Maybe I should get into management after all and make my escape.''

McStay seemed fit and burgeoning with good health when we met. Displaying the same erect, upright bearing with which he patrolled Celtic's midfield for 14 seasons, it was hard to believe he has been out of football for four years. In an age of foreign sophistication littering our fields, though, it isn't forgotten that, beside Kenny Dalglish and Charlie Nicholas, he is a member of the three most naturally gifted footballers reared by Celtic in the last three decades.

At the age of 32, injury put paid to the remainder of McStay's career in 1997. This was a sad loss but, in career terms, it stopped short of being cruel; with medals for three championships, four Scottish Cups, and one League Cup, his plunder hadn't been bad. ''Looking back on it now, having been with a club as big as Celtic, it maybe should have been more,'' he says. ''But, on top of my 76 Scotland caps, I don't think I can complain.''

There remains a dignity about McStay today which was a trademark of his career. On the park, this bashful man almost appeared embarrassed by his wealth of talent, while, off it, he seemed to loathe the fame and celebrity that came with being an Old Firm player. Even today, four years on, he says he is still a little uncomfortable with the attention. ''I was asked for my autograph the other day,'' he says. ''I said to the kid: 'why me?' ''

His sense of modesty and natural disinclination to make a noise hasn't just put off those who have tried to make him a news-paper columnist, offers which he declined. He has also refused to make much of what insiders knew to be an acrimonious split from Celtic before an injured ankle finally forced him to retire completely in 1997.

In those last months of his career as Celtic's captain and probably their best player, there was tension behind the scenes between McStay and Fergus McCann. McStay had agreed in principle, due to his wear and tear, to be used sparingly the following season, before McCann abruptly told him his basic pay would take a swingeing cut. It was an unsavoury episode that left the club's longest-serving player facing a 60% reduction in salary, without any bonuses, and reduced to putting out feelers via friends to any clubs that might employ him.

Around Parkhead today, some still view this incident as one of the stains on McCann's tenure at the club. McStay says he subsequently received an apology from Celtic for his treatment. ''Things are great for Celtic today and I've never had any wish to pass comment on what happened,'' he says. ''But none of it was pleasant.''

There will be a full house at Ibrox tomorrow when Rangers face Celtic. McStay holds the distinction both of playing in a record 66 Old Firm games, as well as being a member of the last Celtic side to win at this ground in August 1994. The years since, he says, have witnessed enormous changes, both in the game and in his own life. None, though, is as dramatic as suddenly having the applause and the spotlight switched off.

''When my ankle injury struck me in the 1996/97 season I knew I had a decision to make,'' he says. ''I'd had three operations on the ankle since 1995 but loose fragments were causing build-ups of fluid and pain. I could still play but, basically, my bones were rubbing together and there was a danger of osteoarthritis. When the surgeon gave me this information, I knew I was endangering my future health and that I had to face reality. I had to get a grip of my life and say, 'you can't go on like this'. It was a hard decision but it was the correct one.

''The hardest part came later in not being involved the following season. It was painful going to Parkhead as a fan and looking out on my former team-mates.

''They won the League Cup against Dundee United at Ibrox that November and I found it tough not being involved. Even today, I can't help looking at someone like Gary McAllister at Liverpool and thinking it could still be me. But I told myself to get a grip, to get on with life, and it's been fine.''

In the time since, McStay has tested himself at a number of pursuits. He has coached some Scotland youth teams under the auspices of the SFA. He did some work for Tony Higgins of the Scottish PFA, visiting clubs and speaking to young players and encouraging them to look to the future. In a private business, he has even dabbled in a property venture. The one thing he has resisted so far is re-entering football as a coach or manager.

''I've had a few offers,'' he says. ''Two specific ones I can think of which I'm glad I turned down. Managing or coaching may or may not come, but, since retiring, I've tried to enrich my mind with things I never got the chance to do while I was playing. In football, as you know, it's just football, football, football. But I enjoyed coaching the youngsters. We all have a different attitude on how football should be played but if young kids learn anything from something you've said, that's a bit special.''

On the subject of the game's future, in fact, McStay provides chimes of optimism. He is the first former footballer of genuine repute I have met who bristles with hope for the game in this country. ''I've seen quite a few youth games out there and there's some real talent about,'' he says. ''I mean, young Scottish kids who have technique and skill and a real ability with the ball.

''In fact, some of them have much more than I had at their age. The question, of course, is whether they will keep the right attitude, and whether the infrastructure is right. But there's hope for us, definitely.''

This from one who, as a young lad in Larkhall, nurtured his own skills which were to so richly bless Celtic. ''As a kid, I loved football, but it wasn't just play, it was always practice,'' he says.

The McStay-Celtic connection is preserved to this day. His brother, Willie, is a coach at the club. His father, John, also does some youth scouting. It is a family connection that seems to go back years, and which McStay is keen to preserve in his visits to Parkhead as a supporter.

Martin O'Neill presumably wouldn't mind having the McStay of his prime as a deep-lying orchestrator for his midfield. It was irresistible, too, to ask McStay what he thought of the current Celtic.

''I think they're amazing; I think the job Martin O'Neill has done is remarkable,'' he says. ''After last season, to be honest, it would have been good just to get the club back on the straight and narrow.

''But then the League Cup came and the title began to linger and the Scottish Cup awaits. It looks like it could be one for the history books.''

Despite better times, Celtic are overdue an Ibrox victory.

If they win tomorrow, their former captain wouldn't mind relinquishing the honour of being among the last to so do.

THE OLD FIRM RECORD

Paul McStay played in a total of 66 Old Firm games during the 1980s and 90s, and was on the winning side 23 times. Of the remainder, 17 were draws and 26 were won by Rangers.

He scored on his Old Firm debut in a 3-2 win at Celtic Park on October 30, 1982 and also in his first game at Ibrox, on January 1, 1983 in a 2-1 victory. In between, he helped Celtic to victory in the League Cup final at Hampden on December 4, 1982. He was to play in eight Old Firm matches before tasting defeat, a 1-0 loss at Ibrox on April 21, 1984.

He was again on target at Ibrox on March 20, 1988 in a 2-1 win which all but clinched the club's centenary season title. He captained the team and scored in the 2-0 league win on August 28, 1994, the last time a Celtic team won at the home of their great rivals.