LONDON - Demonstrators scuffled with police in central London on Wednesday when thousands of students and school pupils protested across Britain against government plans to raise university tuition fees. Signs were thrown at officers and demonstrators attacked a police van as they massed near parliament in central London. Two weeks ago, protesters stormed a building that houses the Conservative Party headquarters in London during the first major demonstration directly linked to the 81 billion pound ($130 billion) spending cuts announced by the coalition last month. Police arrested almost 70 people over the disorder earlier this month which saw windows smashed, objects hurled at officers and an 18-year-old student pleaded guilty on Wednesday to throwing a fire extinguisher from the roof of the building. On Wednesday, young people staged walkouts at universities, schools and colleges in a national day of action at the coalition Conservative-Liberal Democrat government proposals to almost triple tuition charges to up to 9,000 pounds ($14,500) a year. There was a noticeably larger police presence on the capital's streets than two weeks ago when the head of the London police force admitted they had not been prepared for trouble. “Anyone who plans to take to the streets of London intent on disorder, violence and crime should understand that it won't be tolerated and they will be arrested,” said Commander Bob Broadbent, who is in charge of the police operation. Liberal democrats face fury Students have been outraged by the funding plans and are particularly angry with Liberal Democrat legislators, the junior coalition partners, as they all signed a pledge during this year's election campaign to vote against any rise in fees. “We feel we owe it to future generations below us to do something about this and be active about it,” said Jenny O'Leary, 20, one of the noisy protesters, waving placards and blowing whistles and horns in the capital. “Because the country's in debt we can't go to university and it's their fault we're in debt,” said 15-year-old Rosie Dean. “It's not our problem, it's the government's fault.” Protesters later plan to march on the Liberal Democrat party's headquarters and to rally outside Cameron's Downing Street office. Organisers said 20,000 young people were expected to take part nationwide. “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,” said Deputy Prime Minister and Liberal Democrat leader Nick Clegg in a speech on Tuesday night. However, that did not impress his opponents. “Students will take no lectures from Nick Clegg,” said Aaron Porter, president of the National Union of Students. “It does absolutely nothing for public trust in politics to have politicians breaking cast-iron promises they have made to voters.”