Students had travelled to London from universities across Britain for what was meant to be a peaceful demonstration. — Photo by AFP

LONDON: University students smashed their way into British Prime Minister David Cameron's party headquarters on Wednesday during a chaotic protest against the government's plans to triple tuition fees.

Thousands of demonstrators besieged 30 Millbank, running riot through the 1960s office building near parliament, which houses the Conservative Party.

Vastly outnumbered, police were powerless to stop the protesters smashing their way through the entire three-sided glass frontage, storming in and wrecking the lobby.

Running amok, several activists reached the roof of the six-storey riverside block and hurled a fire extinguisher at police below as students crammed into the courtyard, torching a bonfire of placards and surging forward.

One woman police officer was seen being led away from the scene with blood on her face.

Fourteen people were injured, including seven police officers, a police spokesman said. Thirty-two people were arrested for offences including criminal damage and trespass.

Students were marching through London in protest at the university tuition fee proposals Conservatives-Liberal Democrat coalition government, which came to power in May.

Police put the number of demonstrators at 20,000, while organisers said it was nearer to 50,000.

Facing suggestions that officers had lost control of the situation, London's police chief Paul Stephenson promised a full investigation.

“This level of violence was totally unexpected, we need to ask ourselves why,” the Scotland Yard commissioner said.

“The scenes that we have seen both inside and outside Millbank are wholly unacceptable, disgraceful behaviour.

“It's an embarrassment for London and for us.”

Aaron Porter, president of the National Union of Students, called the violence “despicable”.

“Proud of the 50,000 students who have come to protest peacefully. Shame on those who are here to cause trouble,” he said online in a Twitter message.

When riot police finally regained control of the building and forcing students back, the scale of the devastation inside was clear.

The lobby was covered in shattered glass, debris and placard sticks, with the desks ransacked, ceiling air vents ripped down and offensive graffiti spray-painted on the marble walls.

A student from Buckinghamshire New University, who declined to be named, told AFP as he ran from the building with the shell of a television monitor: “It's like a raid in there.”

“The Conservatives are asking for it.”

The 20-year-old said the police had “marched us past here and expected nothing to happen”.

The move to increase tuition fees directly contradicts a pre-election promise made by the Liberal Democrat party of Deputy Prime Minister Nick Clegg, the junior coalition partners.

Students had travelled to London from universities across Britain for what was meant to be a peaceful demonstration.

Protesters waved placards saying: “Stop education cuts” and “9K?! No way!”, referring to the 9,000-pound (14,500-dollar, 10,500-euro) maximum level of the annual fees.

Dylan, 16, from Sussex in southern England, emerged from the foyer wreckage with souvenirs including some 30 Millbank ring-binders, a computer mouse and an “escorted visitor” security pass around his neck.

“It was crazy, quite frightening. I'm upset, angry and worried about whether I'll be able to go to university. It's scary to think I might not be able to afford to go,” he told AFP.

“Ten pounds is a lot of money to me, let alone 9,000 pounds.”

One demonstrator, Bernard Goyber, a 19-year-old reading history at a London university, said: “Students haven't been consulted about the rise in fees at all and universities are being savaged by the cuts.”

“Fifty per cent of students can't get jobs, most students won't be able to pay this back anyway.”

The issue of tuition fees had earlier dominated the weekly prime minister's questions session in parliament, with Clegg answering in the absence of Cameron, who is on a visit to China and the G20 summit in South Korea.

The British police's handling of riots has been under scrutiny since the protests surrounding the April 2009 G20 summit in London.

Police used the kettling tactic, where demonstrations are corralled in one area, and one man walking through the protest zone died shortly after being knocked down by one officer.