Last year, a German website offered what was effectively a “rent a mob” service. For a fee, you could hire young men and women to protest and rally for almost any cause of your choice.

Of course, in many countries, football has long had its own version of this. And while the game’s “rent a mob” doesn’t get paid in cash, it still exacts payment in the form of getting the chance to break things, set things on fire and clash with police. As an added benefit, the mob gets to do so behind the cover of a “cause”, allaying whatever conscientious objections that causing criminal damage might bring.

This year, when residents near Naples staged protests at the building of waste treatment sites near their homes, their ranks were swelled by some of Napoli’s ultras, its hardcore supporters, who, as if on cue, proceeded to engage the police in nightly running battles.

But these actions paled in comparison with what happened last week in Belgrade. When the Kosovo region of Serbia unilaterally declared independence and was soon recognised by a number of world powers, including the United States and the United Kingdom, it led to violent demonstrations.

While ethnic Serbs make up less than 15 per cent of the population in Kosovo, Serbia claims strong ties to the region, which is home to important sites in the Serbian Orthodox Church. Furthermore, they decried what they saw as a double standard: Kosovo can unilaterally declare independence with the blessing of Western powers, but other regions – from the Basque country to Quebec to the Kurds in Turkey – cannot.

One such rally spun out of control on Thursday night. The US Embassy in Belgrade was attacked, hundreds were injured and one protester was killed. Once again, on the front lines, were hardcore supporters of Partizan and Red Star, Belgrade’s biggest clubs.

These are the very same supporters who became infamous when the former Yugoslavia fell apart in the early 1990s. Back then, Zeljko Raznatovic, better known as Arkan, was one of the leaders of Red Star’s Delije ultras. Arkan also headed up a vicious paramilitary group, the Tigers, whose ranks were made up of hardcore fans of Partizan and Red Star, who put their rivalry aside in the name of Serbian nationalism.

The next generation of Red Star and Partizan hooligans (with a smattering of old-school types) led the charge on the US Embassy, bringing back memories of the horrific four years of war in the region that started 17 years ago. As well as drawing universal condemnation, the protests brought forth the old mantra that politics and sport “should not mix”. This notion may be a tempting idea, but it’s a silly one, too. Public figures have been drawn into political conflict ever since political debate entered the public arena. Whether it’s Sean Penn on Iraq or Oprah Winfrey on Barack Obama, whether it’s Vanessa Redgrave on Oscar night or John Lennon in his hotel bed, they have weighed in with their views.

And, for better or worse, it so happens that many of Serbia’s public figures (as is the case with neighbouring Croatia’s) are world-class athletes. Thus Dejan Bodiroga, the legendary basketball player, and Novak Djokovic, the tennis star, addressed the crowds at the rally. At a time when we chastise our sports stars for being interested in little more than money, sex and videogames, it’s actually quite refreshing that they have opinions.

Value judgments aside, Tommie Smith’s “black power” salute after winning the gold medal in the 200 metres at the 1968 Olympics in Mexico City was roundly condemned at the time (a suspension and death threats followed). Today he is remembered as a hero.

Bodiroga and Djokovic may see themselves in the same way. But what of the rioting Partizan and Red Star supporters? There the issue is more complex. When you riot most weeks, the mere fact that, in this particular week, you claim a reason to do so does not make you a hero or an idealist. It simply provides you with a convenient excuse. And it would have been smarter to riot without wearing your Partizan and Red Star colours.

For all their demonisation, many of these self-described hooligans are simply hyperactive twentysomething men who enjoy a fight. Nothing less, nothing more. The only thing that sets them apart from their counterparts in other nations – such as England – is that they band together under certain colours and symbols. But their ethos, a love of fighting and rioting, is no different. And that’s what makes them so prone to being manipulated.

All you have to do is give them a reason to fight and they’ll be on board.

Shoe doesn’t fit Juve

For years, referees in Serie A were accused of favouring Juventus, culminating in the 2006 Calciopoli influence-peddling scandal. Now the shoe seems to be on the other foot. On Saturday, Juventus were denied what appeared to be two clear-cut penalties against Reggina, while their opponents were awarded a highly dubious spot-kick in stoppage time. They lost 2-1 and even the normally understated Claudio Ranieri, their coach, said: “It’s just the tip of the iceberg.” Indeed, Juventus have been complaining about the officiating all season long.

Is it just a case of match officials making honest mistakes that happen to damage Juve? Are referees worried, given recent events, of being seen to favour them and therefore overcompensate by going in the opposite direction, which would mean that Juventus are still paying for their misdeeds? Or is there a widespread plot?

Conspiracy theorists are having a field day. And the sad thing is that, because of Calciopoli, there is a sense that you cannot rule anything out.

France strike it rich

If commercial agreements with kit sponsors are a bellwether of things to come, it may be time to put your eggs in France’s basket. Nike’s agreement with the French FA will provide Les Bleus with £32 million a year between 2011-18. It’s a deal that dwarfs all previous national team sponsorships and ends France’s 40-year relationship with adidas. With a gaggle of budding stars on the horizon, such as Karim Benzema, Hatem Ben Arfa and Samir Nasri, it may be money well spent.