Football can be childish at the best of times, but never so childish as when it elects to pose the original, prize-winning playground question: who started it?

Back in the real world, we know the answer rarely matters much. We also know, thanks to certain of our distinguished statesmen, that all conflicts contain the potential for escalation. If we have any sense, we also realise that complacency is the enemy of everyone's security. History is always repeated.

Did football truly kick out racism? Only in some places, some of the time. Is hooliganism a thing of the past? After last week, only an idiot would cling to that forlorn hope.

It doesn't matter whether Manchester United fans were provoked or Roma's support insulted. It won't do - and will in fact make matters worse - to talk of Lille as an "ambush", or suggest that policing in Pamplona somehow explains the all-purpose bigots who stain the name of Rangers.

Clive Allen, the Spurs reserve coach, is perfectly entitled, for one, to believe that the behaviour of the Seville police was "disgusting" last Thursday. If a disabled Tottenham fan was in fact clubbed there can be no excuses, just as there can be no excuses for the amateurish brutality of the Rome carabinieri when confronted with a few Manchester United casuals.

But if you say that, what have you said? That cops in Manchester had best tool up for an influx of Roma ultras? That a presumption of guilt is at work, these days, where travelling British fans are concerned? That our sporting ambassadors are therefore unblemished innocents? Be serious, instead, and pay attention to the real problem.

Real trouble is brewing within the European game. Racism has become commonplace, once more, in certain countries. An Italian policeman has died. In France, clubs have been condemned to play behind closed doors. In Spain, politics, sport and violence have mingled. Parts of eastern Europe and Turkey are so grisly they are barely worth contemplating. Who wants another Heysel? The question is not rhetorical.

Home Secretary John Reid is a populist of the old school. His interventions are rarely accidental. It is part of his job description, nevertheless, to ensure the safety of British citizens. More to the point, when he voices doubts about the quality of policing in France, Italy and elsewhere we are entitled to believe he is acting on information received. Then again, anyone who saw the pictures from Rome could arrive at their own conclusions without the benefit of "intelligence".

Young, scared, badly-trained officers should not be involved in crowd control. As Rangers pleaded last weekend, the practice of selling tickets to all-comers on match days needs to be investigated as a matter of urgency. Then - though let's try to avoid pomposity - the psychology of football tribalism requires some serious work.

Who ever believed that the nutters simply went away? One lot simply grew a little too old for brawling. That doesn't count as a solution if, as always happens, psychosis is transmitted across the generations. Violence in football is cyclical and it may be that another phase is upon us.

Consider Manchester United's troubles in Rome. This is not a club with a tradition of hooliganism. Yet as one of my colleagues observed last week, Celtic somehow managed to take thousands of supporters to Italy without a hint of trouble. Manchester - having issued an ill-advised and possibly provocative "warning" to its fans - found itself in a war-zone. It takes two to ruck.

We know how some of this works. One spot of bother inspires "retaliation". Fans thousands of miles apart become "enemies". Violence becomes "traditional". The police over-react; someone dies; and the cycle continues. It's called giving the customers, the sane ones at least, the last thing they want.

In Scotland, we know a bit about this. It was our honour, once, to be known as the thick man of Europe. If Scottish fans were present trouble was all but guaranteed. Yet somehow the Tartan Army got a grip. Perversely, almost comically, they decided to be "the best fans in the world". The last time I saw Scotland play England at Hampden it was the visiting support who were itching for bother. And nothing much happened.

I grant you this doesn't count as a sure-fire answer to all woes. I'm fairly sure I know how Old Firm fans would have responded to the policing favoured last week in Rome and Seville. Even the Tartan Army does not meet my definition of cuddly. And it only takes a few dozen, for things to kick off. The point is that mayhem is not inevitable.

Equally you cannot legislate for those strange generational shifts. I would happily argue that Britain's police, granted some bitter experiences, are more sophisticated than many of their European counterparts when it comes to handling psycho casuals. I'd even accept that those rotten plastic seats we nostalgics hate have made British grounds calmer, safer places. But are there fruitcakes just around the corner? Always.

The stakes are higher, these days, than in the 1970s and 1980s. Football, as the cliché-mongers remind us, is a part, a big part, of the global entertainment industry. What would another Heysel do for its image? We saw the reaction in Italy recently to the murder of one policeman. Some say the authorities there did not go far enough. But if sport becomes a magnet for fascist killers, how far is far enough?

These are not cheerful thoughts for a holiday weekend. To complete the mood, nevertheless, I would add this: never imagine that the 21st century British fan is immune to the old diseases. And if there is another tragedy, home or abroad, the sport will be in deep, perhaps permanent, trouble.