Nobody needs to preach to me about the complexity of bigotry. Sometimes explicit, sometimes subliminal, sometimes clouded by humour, trying precisely to trace a bigot is a vulnerable and dangerous task. There are some strands of

evidence, though, which can be presented without argument.

Let us suppose, in the case of prejudice against Catholics, that someone regularly and with great relish refers to someone else as ''a Fenian bastard''. Or suppose, with equal fervour, they enjoy singing about someone ''dying a Fenian bastard'' or of being ''up to our knees in Fenian blood''. Or consider even the plain, less adorned chant of ''dirty Fenian bastard''.

Now this is language, uttered without fear or inhibition, which can be taken as evidence of

bigotry.

This was Rangers chairman David Murray's major problem three days ago. Following comments made by the Celtic manager, Martin O'Neill, about bigotry at Ibrox last weekend, the irony was that it was Murray who was suddenly on the back foot. Murray was forced to come out and defend his club's supporters, yet he knew he had a difficulty. His problem was that, at Ibrox, hordes of Rangers supporters routinely shout and chant bigoted slogans.

''We should guard against broad generalisations [about] our fans,'' said Murray in response to O'Neill. But it was the subtext of this remark that was telling.

Murray knows, as everyone else knows, that the atmosphere of Ibrox on match days can be thick with bigotry.

Around almost every corner of this sensitive subject, you have to apply checks and balances. Rangers should not be tarred exclusively with the sectarian problem, because Celtic suffer from it as well. In this specific context, though, we are dealing with Rangers and Ibrox, precisely because of what Martin O'Neill said earlier this week. Moreover, at Rangers, by general consent, the sectarianism is worse than it is at Celtic.

The outcry over O'Neill's comments in Barcelona about the bigotry of many Rangers supporters has been extraordinary. Although he was goaded into making his remarks, what O'Neill said was the essence of truth and he deserves great credit for saying what he said. Last Tuesday evening, O'Neill claimed that there had been ''racial and sectarian abuse'' of his players at Ibrox when Rangers played Celtic last weekend, and that at times, it had reached ''an incredible crescendo''.

Speaking from a media perspective, I hardly know a reporter or an observer with any experience of Ibrox who would deny what O'Neill said. Personally, I have been going to Ibrox, man and boy, for 30 years and would certainly concur with O'Neill. Some among us might not like the fact. Others may prefer to keep quiet about it or even erase it from our consciousness. Others might even be embarrassed about it. But I'd like to find a convincing man or woman anywhere who would be willing to stick up their hand and say:

''Bigotry at Ibrox? Not true.''

What was mystifying was the remarkable controversy following O'Neill's comments, as if he had said something plainly preposterous or delusional in nature. Every sentient person I have spoken to about O'Neill's remarks has congratulated the Celtic manager for saying what most observers in Scotland have been stating for 50 years. Yet there is still an impression somewhere out there that O'Neill was in the wrong.

The fact is Rangers cannot crush their sectarian problem. Years ago, David Murray referred to the Rangers supporters as ''an embarrassment'' because of their bigoted chanting, yet try as Murray might, or try as Martin Bain, the club's director of football, might, they cannot erase the stain. These days at Ibrox on match days, the idiom of bigotry is as prevalent as ever.

In these debates, you cannot just indulge in unsubstantiated or time-worn hunches. Instead, you must present cold evidence born of experience. So from myriad

examples in my own experience, let me provide one concrete case from Ibrox and the Old Firm game last Saturday.

As it so happened, I gave up my usual seat in the press box to a Sunday newspaper journalist, whose immediate need for working space was more pressing than my own. Hence, I made my way to a different seat at Ibrox, with greater proximity to the Rangers supporters. It was an experience that reminded me again of how widespread and malignant bigotry at Ibrox is.

From too many mouths to count, people like O'Neill and Neil Lennon, the Celtic midfielder, both Catholics from Northern Ireland, were subjected to sustained

sectarian abuse throughout the match. It is worth actually citing these slogans. They ranged from ''Fenian c***'' to ''Fenian scumbag'' to - in the case of Lennon - ''away and f*** yersel, Lennon, ya Fenian bawbag''.

A Rangers supporter sitting close to me, and representing that great strand of decent Ibrox supporters who must be routinely embarrassed by all this, said to me jocularly at half-time: ''You'll note that we are among the discerning Rangers supporters up here.'' He was joking, but his sarcasm made the point. It was a rotten, ignorant, venom-filled atmosphere, which Martin O'Neill, three days later in Barcelona, would quite rightly describe as bigoted. Yes, it is a

subtle business actually ''defining'' a bigot. Yes, a 90-minute bigot on a Saturday afternoon doesn't

necessarily mean full-blown

bigotry in the rest of an otherwise decent citizen's life. Yes, inhibited people often bow to peer-pressure and join in such chanting when they'd rather not.

The very least you should be, though, is suspicious of such behaviour. In many cases there is simply no doubt about it. If the diagnosis of a real, genuine bigot proves too subtle to perform, then the only response can be the one I gave to the very likeable Donald Findlay, QC, when he denied being a bigot after resigning in disgrace as vice-chairman of Rangers.

''Donald, I don't know if you're a bigot or not,'' I told him. ''All I know is that you acted like one.''

For too many people in the

raucous atmosphere of Ibrox, the shouting and singing amount to prejudice. From my point of view, if innocents are otherwise tarred by such allegations, then I simply have to keep apologising to decent supporters who feel the rough edge of a critic's pen.

Just don't deny the unavoidable truth that here in 2004, an alarming number of Rangers supporters, as David Murray well knows, are bigots.

It is folly, not to say a cultural disservice to Scotland, to denounce O'Neill for what he said this week, and I say this as one who is only too aware of the futile and dramatic exaggeration of bigotry in our country. Five years ago, when the composer James MacMillan, in his famous outburst, claimed that such places as Scottish Television and BBC Scotland were ''jam-packed with bigots'', I regarded it as plainly absurd, a mis-use of language. But Martin O'Neill's comments this week carried a distinctive, more authentic tone. O'Neill knew what he was talking about and he hit the truth dead-on.

O'Neill, I believe, is the first Old Firm manager in 30 years to offer such a bold and unequivocal condemnation of the sectarian problem. For that fact alone he deserves credit, though it begs an old question from some of us: why is it that the managers of Rangers and Celtic, who find themselves at the very centre of this blight, should be so routinely silent about it?

Alex McLeish, the Rangers manager, is, to use the vernacular, a top bloke. Anyone, like me, who comes across McLeish will vouch not only for his milk of human kindness, but also his charm, thoughtfulness and strong humanity. Yet what I would give for McLeish one day to say: ''You know what? I love football, I love Rangers and I love the passion of our supporters. But bigotry is something I detest to my very core, and I wish those Rangers supporters who indulge in it would stop embarrassing themselves, our club and me.''

Those of us who inhabit the football world have a favourite cliche about all this. We say of

bigotry: ''It's not football's problem, it is society's problem.''

Well, yes, this is self-evidently true, and the medicine for it all surely lies in education. But football shouldn't be too dumb to speak up about the problem. Nor should we go mute when seeking to apportion blame in the endless, tip-toeing sensitivity about what attaches to Rangers and what to Celtic. Rangers, in particular, have a major problem with bigots, which I believe the club is trying to address. Martin O'Neill, meanwhile, deserves credit for having the courage to talk about it.