|Series of events planned in the second stage of protests across UK [Jacqueline Head, Al Jazeera]
Students and school pupils have staged protests across the United Kingdom against government plans to raise university tuition fees, two weeks after a demonstration in central London turned violent.
At least 29 people were arrested as thousands of campaigners took to the streets in London, many holding anti-government placards and chanting "no ifs, no buts, no education cuts".
"There is a very heavy police presence - tens of vans, horses, motorbikes and scores of officers," Al Jazeera's Jacqueline Head, reporting from the scene of the demonstrations in London, said.
"In front of them is a very loud crowd shouting their opposition to the tuition fee hike.
"Protesters are burning placards sending up a huge cloud of black smoke. Riot police and horses have been sent in."
TV footage showed a police vehicle surrounded by a crowd of protesters, some of them hitting it with bars and sticks, while others had climbed on top of it. Small groups of protesters were also seen hurling placards at officers
Lib Dem focus
The protests were planned after the Conservative-Liberal Democrat coalition government proposed to almost triple tuition charges to up to $14,500 a year.
Two weeks ago, protesters stormed the Conservative Party headquarters in London. It was the first major demonstration directly linked to the $130bn spending cuts announced by the government last month.
Al Jazeera's Head said that the police appeared to have a strategy to contain Wednesday's protest, after the violence at the previous demonstration.
"They've moved in and 'kettled' the protesters about 200 metres from the Houses of Parliament. Its proving effective right now. No one is getting in or out."
Line of police formed barriers across streets in Whitehall and prevented the protesters from marching to their intended target, the headquarters of the Liberal Democrat party.
"The majority are acting peacefully and we are working to keep the protest as peaceful as possible," police said.
However, two police officers were injured in the protests, one with a broken arm and the other was knocked unconscious, police said.
The head of the London police force had earlier acknowleged that they had not been prepared for trouble during the last protest, but this time senior officers say that they are ready for any eventuality.
Violence 'not acceptable'
David Cameron, the prime minister, described the violence two weeks ago as unacceptable and his spokesman said that he was "looking forward to a peaceful protest" on Wednesday.
Students and campaigners have been outraged by the plans for university funding.
Their anger is particularly directed at Liberal Democrat politicians, as they all signed a pledge during this year's election campaign to vote against any rise in fees.
Nick Clegg, the Liberal Democrat leader, has defended the plans in a speech saying that the policy was the best available in the circumstances.
"I make just one request of those planning to protest: examine our proposals before taking to the streets. Listen and look before you march and shout," he said.
There were also demonstrations on Wednesday in university towns and cities elsewhere in the country, including Bristol, Liverpool, Sheffield and Leeds.
In Cambridge, hundreds of students scaled the fence outside Senate House, the building used for graduation ceremonies, and marched into the grounds of the 700-year-old King's College shouting and waving placards.