Addressing reporters, Cameron defended the government's contentious move to triple tuition at UK universities and said protesters, not the police, should be blamed for last night's chaos on Parliament street and nearby areas and for attacking a car transporting Prince Charles and Camilla, the Duchess of Cornwall.
"I immediately rang the Prince of Wales," said Cameron, a reference to Prince Charles. "We need to learn the lesson of this incident," he said.
On Friday, police sifted through rubble strewn over London's Parliament square, searching for clues and culprits in Thursday night's protests, where students, enraged by the triple tuition hike, broke windows and ambushed the royal vehicle.
"It is not the fault of the police," said Cameron. "It was the fault of those who tried to smash that car."
A photo of the royal couple, dressed in evening wear, made headlines as it showed the startled expressions on their faces as they sat in their Rolls-Royce before exiting for a Royal Variety Performance.
The royal couple escaped unhurt. Police said the route had been cleared minutes before the royal couple was due to make their journey.
The high-profile incident came late in a day of violent protests that left at least 12 officers and 43 demonstrators hurt.
London's Metropolitan Police issued a statement Friday condemning the protests and alleged vandalism that took place Thursday night, claiming protesters intimidated Christmas shoppers and bystanders.
"This has nothing to do with peaceful protest," the statement said. "Students are involved in wanton vandalism including smashing windows in Oxford and Regent streets."
So far, 34 people have been arrested in connection with the protests, and more than 40 protesters have been hospitalized, police said.
The protests 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 a year. In U.S. dollars, that's a nearly $10,000 a year 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 ended hours of debate inside Parliament. Thousands of demonstrators outside said 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.