December 9, 2010 -- Updated 2006 GMT (0406 HKT) The royal car sits outside the London Palladium following the attack. STORY HIGHLIGHTS London (CNN) -- Protesters enraged by a Parliament vote to triple university tuition rates attacked a car carrying Prince Charles and Camilla, Duchess of York, Thursday night. The demonstrators broke a window and tossed paint on the car, however neither royal family member appeared to have been injured in the attack. The attack followed a vote in the House of Commons to approve a plan to raise the existing cap on tuition rates charged by universities from £3,000 to £9,000. In U.S. dollars, that's a nearly $10,000 increase -- from roughly $4,700 to $14,000. Lawmakers approved the plan in a 323-302 vote. The measure awaits approval by the House of Lords and a signature by the queen before it can become law. The vote capped hours of debate inside Parliament and an all-day protest by thousands of demonstrators outside who say the plan will price many students out of a university education. Supporters say the tuition cap hike is needed to cut the government's massive deficit. In recent weeks, the proposal has spawned multiple public protests, set off tremors within the nation's coalition government and prompted a back-seat revolt among some Liberal Democrats in Parliament. Liberal Democrats are lesser partners in a coalition government ruled by Conservatives. The London protest started out peacefully Thursday, but grew more tense with the winding down of debate in the House of Commons. By late afternoon, police on horseback attempted to push back throngs of protesters moving on Parliament. UK students protest tuition hike UK students plan 'Day X' protests Police injured in UK student protests Students reacted by throwing sticks and setting off fireworks. After the vote, riot police were called out to quell disturbances in Trafalgar Square, including the setting afire of a Christmas tree. Before the fire was set, a demonstrator was seen climbing the tree. Authorities said nine police officers and 22 demonstrators were injured in the scuffles. One officer was hospitalized after falling from his horse, another suffered a serious neck injury after being knocked unconscious, the Metropolitan Police said. No details were given on the other seven officers. The police service announced the arrest of 15 protesters on charges ranging from assauliing a police officer to drunk and disorderly conduct. Protest organizers had urged demonstrators to show restraint. Earlier this month, police arrested a total of 153 people following another protest at Trafalgar Square during which students damaged a police van, set small fires and spray painted and smashed government building windows. One final-year student, standing in front of police lines outside Parliamen on Thursday, told CNN he was there out of solidarity with students who may be priced out of a place at university. "We're all here because we're passionate about this. We feel betrayed," he said. Prior to vote, another protester screamed, "Nick Clegg ... you're a sellout! You have betrayed us!" The protester was referring to the British deputy prime minister and Liberal Democratic Party architect of the coalition government. The government is headed by Prime Minister David Cameron, a conservative. Clegg supports the tuition increase plan. At least a dozen other party members, including deputy party leader Simon Hughes, said they oppose it. Supporters say the tuition cap hike is needed to help pay down the government's massive debt. They argue the increase is not mandatory, that universities would not be bound to charge university students the full £9,000. Under the new plan, students wouldn't have to start paying off their school loans until they begin earning at least £21,000, about $32,600, a year. Students currently must start paying off their loans once they reach a £15,000 (roughly $23,300) threshold.