As I walked across Rome in a bid to locate the protest that would make headlines around the world on Saturday, I was stopped abruptly by a densely packed row of huge police vans blocking the main avenue in front of the Colosseum.

Hundreds of riot police with helmets, batons and tear-gas were ready for the slightest provocation and the mood was ominous as about 200,000 demonstrators were snaking down one of the city’s main thoroughfares, Via Cavour, in their direction.

Smoke could be seen spiralling from a couple of rooftops and colleagues sent me messages to say that shops and banks were coming under attack in the area.  It was early in the afternoon but the police would not let me through.

After walking for more than a kilometre, I found a break in police ranks and joined a largely peaceful crowd with signs including one with John Lennon’s famous lyrics: “You may say I’m a dreamer but I’m not the only one.”

Before this demonstration was brutally hijacked by a small number of hoodlums who wreaked havoc, it was an expression of solidarity for the Wall Street occupation and a protest against Prime Minister Silvio Berlusconi’s callous obsession with his own self-interest at a time of  real economic upheaval.

This was all about the broken dreams of ordinary people — from  the unemployed to the university graduates, who, irrespective of their education or talent, have little hope of finding a job in Italy without a  “raccomandazione” or personal connection.

Many of the demonstrators were like Claudia Pagnini, an 18-year-old high school student who carried a small sign with a plaintive cry: “What will my future be?”

She was among 50 young students who travelled for four hours by bus from Viareggio in Tuscany to protest against the government and its failure to resolve the economic crisis or offer policies for the future.

“We are here to protest against the government, the opposition doesn’t exist any more,” Pagnini told me. “Even if they don’t care, this is worth it because we have to demonstrate our opposition.”

Her 18-year-old friend, Lucrezia De Paulis agreed.  “Why are we the only ones who have to pay?” she said referring to the recent austerity measures passed by Parliament. “Berlusconi has exploited politics for his own ends. He no longer represents a democratic choice.”

This protest initially drew sympathy from the head of the Bank of Italy, Mario Draghi, but that move was completely overtaken later in the day by the worst violence that Rome has seen in decades.

At least 12 people were arrested and more than 130 people were injured as masked youths, reportedly linked to a loose alliance known as the Black bloc, went on a rampage brandishing sticks , hurling fire extinguishers at police and setting cars alight.

Some of the heaviest conflict took place next to the Basilica of St John Lateran, one of Rome’s four papal basilicas, and peaceful protesters were forced to seek refuge in nearby churches while shouting at the dissidents, “Shame on you, you have ruined everything!!”

On Sunday, city workers began cleaning up an estimated €1.6 million ($2.1 million) worth of damage, as stunned Romans asked how the hoodlums — who reportedly travelled from as far as Naples, Bari, and Syracuse — were allowed to strike their beloved capital.

Berlusconi was quick to condemn the violence and blamed the opposition for fuelling a “climate of civil war”, while Rome mayor Gianni Alemanno, once the youth leader of a neo-fascist party,  said the city would suffer from  “moral damage” for some time to come.

Late Sunday police said four young women and several minors were among those arrested over the attacks.

So where does that leave those young students who travelled for hours from all over the country to find their voice on the streets of the capital?

They still face little prospect of employment and ever higher taxes to pay the ballooning public debt they have inherited from their parents in a country desperately overdue for economic reform.

But worst of all, the country’s 75-year-old leader, who narrowly won a confidence vote in parliament on Friday, appears more concerned about safeguarding his future than theirs.