In Strasbourg, an assistant referee is hit by a firecracker during a French first division match. In Milan, a Molotov cocktail is thrown at the coach carrying the players of Internazionale. In the Argentine province of Isidro Casanova, a 17-year-old boy is killed during rioting between the supporters of two neighbouring second division clubs. In Nicosia, players' dressing-rooms are besieged and a stadium is severely damaged after a referee ends a derby half a minute before the end of the indicated stoppage-time.

In the Netherlands, Den Bosch supporters riot for three days and nights after the cancellation of a match following the shooting of a fan by police. In Rio de Janeiro, the climactic match of the Brazilian championship has to be replayed after 60 people are injured in a fracas sparked off when two spectators - fans of the same team - start fighting. In Oslo, meanwhile, the Nobel committee announces that the game of football has been nominated for this year's Peace Prize. French referees, who threatened a national strike this week unless their federation takes action, and Italian players, who held up the kick-off of their pre-Christmas matches by 15 minutes to protest against the rising tide of violence, might not be impressed by the gesture.

In England, too, aggro seems to be back in fashion. A few weeks ago several hundred fans of Manchester United and Leeds United, en route to matches at Bradford and Maine Road respectively, met in Rochdale for a Saturday morning head-to-head. Pitched battles in the centres of Sheffield and Burnley have followed recent derbies. On the internet, gangs associated with Queens Park Rangers and Arsenal exchanged taunts about last weekend's fighting in the streets around Loftus Road.

These events appear to contradict the image that football is trying hard to create. After several decades spent skulking in society's shadows, the game seemed to emerge during the 1990s into a world of light and joy and festivity. If Nick Hornby's Fever Pitch provided the prologue to this new football culture, then its defining event was surely the party on the Champs-Elysees on a summer night in 1998, when more than a million citizens of France celebrated the winning of the World Cup. When English fans rioted in Marseille during that tournament and again in Charleroi two years later, their misbehaviour was dismissed as a mere echo of the past.

But the catalogue of recent events suggests that football's social makeover may have been less than entirely successful. The new image may, in fact, be no closer to the truth than the old vision of uninterrupted mayhem which made it a pariah sport in the 1980s.

"Only God, if he exists, would know what the present rate of football hooliganism is," Professor Eric Dunning said this week. "What we can say for certain is that in the last two years the reporting of hooliganism in the media has increased."

Dunning's work at the University of Leicester's Centre for Research into Sport and Society made him one of the world's foremost experts on the sociology of football-related violence, which he refuses to see in terms of the conventional definition - a single phenomenon caused by a mixture of the effects of drunkenness, unemployment, violence on the field of play, and the permissive society.

His analysis tends towards a view, expressed in a recent article in the European Journal on Criminal Policy and Research, that football hooliganism is "basically about masculinity, territorial struggle and excitement . . . fighting is a central source of meaning, status or `reputation' and pleasurable emotional arousal".

"Football is the world's most popular spectator sport," Professor Dunning continued, "so I don't think it's surprising that it should be the vehicle for what you might call the pathologies or the fault-lines of organised societies, which might include racial, tribal or sectarian differences."

In England, that fault-line is generally the one running between two neighbouring clubs. "The hard core of English hooligans, like the Chelsea Headhunters, have an interest in getting publicity for what they're doing, either for the National Front or simply for themselves," he said. "But there are people whom we've come to call football hooligans who just like a punch-up."

After watching the England fans rioting in Charleroi during Euro 2000 on his hotel TV, the Italian player Angelo di Livio asked a reasonable question: "How is it possible that such an advanced nation can't shake off this plague?" But this season Di Livio's own nation has been the epicentre of football-related violence.