Tens of thousands of students have protested against plans by the British government to raise university tuition fees, smashing windows and lighting fires in London, the capital.
Wednesday's protest near the houses of parliament was the largest street demonstration in the country since the government announced tough austerity measures to curb public deficit.
Some students attempted to force their way into the party headquarters of David Cameron, the prime minister, forcing the building to be evacuated.
Several dozen protesters managed to get into the lobby of the building, while outside police faced off
an angry crowd.
"We are destroying the building just like they are destroying our chances of affording higher education," said Corin Parkin, 20, a student at London's City University.
Student leaders, who said about 50,000 people had marched through central London, condemned the violence as "despicable".
The police reported that 14 people had been injured, including seven officers.
Jonah Hull, Al Jazeera's correspondent in London, said: "Fifty-thousand people were on this march, and we were with the march at the beginning, and it was a peaceful march, and there's no question about that.
"This was not a march full of groups hell bent on causing violence in the city of London.
"However, within their numbers, as is very often the case of course, there are these groups that infiltrate, namely the anarchists ... I've certainly seen anarchists' flags."
Wednesday's rally was held to protest against the decision by the coalition Conservative and Liberal Democrat government to raise the cost of studying by up to $14,000 a year.
"I am here because it is important that students stand up and shout about what is going on," Anna Tennant-Siren, a student at the University of Ulster, told the AP news agency.
"Politicians don't seem to care. They should be taking money from people who earn seven-figure salaries, not from students who don't have any money."
The move to raise fees has also sparked anger as it contradicts a pre-election promise made by the Liberal Democrats, who had said they would abolish fees.
Protest leaders have said they would attempt to use recall powers to oust politicians who break campaign promises on the issue.
The National Union of Students said it would try to recall legislators from the Liberal Democrats who vote in favour of the increase.
"We will not tolerate the previous generation passing on its debts to the next, nor will we pick up the bill to access a college and university education that was funded for them," Aaron Porter, president of the union, said.
The previous Labour government introduced the first fees for students soon after it was elected in 1997.
Scotland abolished tuition fees in 2000, and in the rest of Britain the cost is capped at about $4,800 a year.
The coalition government plans to triple that and cut funding to universities as it strives to slash $128bn from public expenditure over the next four years.