Stephen Kirk, the best amateur boxer in these islands, used to say, "getting up in the morning for a run is the hardest bit. When the alarm goes off at five all I want to do is turn over again." That was the closest the world light-heavyweight bronze medallist ever came to moaning or complaining and, in a boxing culture sometimes characterised by ego and macho bravado, his modesty was as rare a thing as a broad smile of contentment across the features of Brian Mullins.

Last week, Kirk should have been completing his preparations for the Commonwealth Games later this month in Kuala Lumpur with the glint of gold in his sights. After that, he had a plan of sorts. The professional sharks had been biting at his door for a few years now and he had more or less made up his mind to rise to their money-dripping bait. Modern amateurs have tended to struggle in recent years with the transition to the paid ranks but Kirk's clubbing left hand and aggressive style augured well for a bright professional future.

But that is all changed and the dreams of gold and future riches are now just so much dust slipping through Stephen Kirk's fingers. Last Thursday started off like any other day - some light training, a team meeting at a Belfast hotel and then the familiar routine of the mandatory pre-Games medical. Kirk has travelled back and forward across the boxing world and is a seasoned veteran of the routines and rituals of the game.

So when some concern was expressed after his brain scan, he had a fairly strong indication that there were serious problems. Anxious to protect the health of the fighters and to avoid the merest semblance of negative publicity, boxing now acts quickly and decisively on even the hint of any scan abnormalities and Kirk had 24 hours to wait for the inevitable. On Friday evening it was confirmed by Dick McColgan, the Commonwealth Games chef de mission, that Stephen Kirk had been withdrawn from the team on medical grounds.

A boxer for over 15 years, Kirk's career was over in an instant.

"I'm just devastated, it hasn't sunk in yet," said Kirk. "At times I still keep thinking that I'll be boxing again but I know that won't happen. I was ready to turn pro. I had my mind made up but now it won't be happening."

And the sporting world here will be a poorer place without him because Kirk was that most unusual of things here, a sportsman for whom barriers of any kind meant nothing at all. Life was uncomplicated and for Kirk it was about boxing and very little else.

That vision coloured everything he did. Living on the Woodstock Road in east Belfast and working as a mechanic in the shipyards of Harland and Woolf, Stephen is from a resolutely Protestant working class background. But yet, he had no problems about boxing for Irish titles (he won three in his career) and representing Ireland with distinction at last year's world championships in Budapest.

That career path has clear echoes of Wayne McCullough's journey through the unpaid ranks. The former world champion is from a very similar background to Kirk - Belfast's predominantly Protestant Highfield Estate - and he too plied his amateur trade in the green vest of Ireland, most memorably with a silver medal at the Barcelona Olympics in 1992. The incongruity of McCullough returning to Dublin Airport on that tumultuous homecoming night to a backdrop of omnipresent Tricolours wasn't lost on anybody here, not least on Highfield Estate, but was met with a certain degree of equanimity.

For it is one of the shibboleths of Northern sport that boxing is different.

"Different" doesn't just mean "mixed" in the way that say soccer, rugby or cricket are, at least on paper, "mixed". Boxing's distinguishing characteristic is its true, uncompromising "integration" and that, in the North's political Doublespeak, is something completely different.

The territories of Belfast's boxing clubs are very clearly marked from the Catholic New Lodge to the Protestant Shankill but they are places devoid of the old tribalism, bitterness or sectarianism. And when the pick of those boxers come together for a major championship or an international match they are genuinely integrated occasions.

Earlier this year at the Ulster finals (which, incidentally, Stephen Kirk missed because of a mixture of injury and fatigue) a contingent of Dungiven gaelic footballers which included Kieran McKeever and Joe Brolly arrived in force at the Dockers' Club in Belfast to support their team-mate Paul McCloskey who had boxed his way into a final.

In any other social situation the prospect of Derry gaelic footballers sitting side by side with east Belfast boxing fans would be almost unthinkable but a tremendously atmospheric night passed without even the hint of rancour. And, of course, the fact that McCloskey was a most impressive winner helped the Dungiven party to swing.

Professional fight nights at the Ulster Hall or the Kings Hall are similarly mixed occasions. They pour in from all over the city, from the working men's clubs on the Falls and the Shankill and, for one night only, sit side by side. It all has very little to do with politics and it would be naive to suggest that it's evidence of some great sporting ecumenical movement. But it happens, and in the context of the strait-jacketed way so many people here live their lives, that is something to celebrate.

With his uncomplicated dedication to his art, Stephen Kirk played his part in local boxing's prevailing atmosphere of positivity. A comprehensive winner at the Commonwealth Games warm-up tournament in South Africa two years ago, he was a banker for a gold medal in Malaysia.

Instead, he has to walk away from it all with only a front-room of trophies and medals to show for a childhood, adolescence and young adulthood given to the sport of boxing. It puts whingeing footballers complaining about unacceptable £20,000 bonuses into their proper perspective.

Because today, tomorrow, next week and for the winter months to come Stephen Kirk will not be able to grumble about dragging himself out of bed for those punishing early morning runs. He will not have to worry about juggling a full time job in the shipyards and the pressures of preparing for international competition. Disputes and disagreements about grants for training funds and travel to international competitions will pass him by. And that is the saddest thing of all.