Police believe that crowds of students protesting about tuition fees last week were infiltrated by "organised groups of hardcore activists and street gangs bent on violence", Home Secretary Theresa May has said.

Mrs May said that police had already received a good public response to the publication of photos of suspected ringleaders and she expected significant numbers of arrests.

Some 35 people were arrested on Thursday as the demonstration against the tripling in university tuition fees descended into scenes of violence across central London, including an attack on a car containing the Prince of Wales and Duchess of Cornwall.

Following speculation that Camilla was struck by a stick pushed through the window of the royal couple's car, Mrs May confirmed that "there was some contact made".

Earlier Charlie Gilmour, the son of Pink Floyd frontman David, was released on bail after being arrested by Scotland Yard on suspicion of violent disorder and attempted criminal damage of the Union flag on the Cenotaph during the protests.

The Home Secretary called on student leaders unequivocally to condemn the "appalling" scenes of violence, and told the House of Commons: "This Government is determined to protect the right to peaceful protest, but violence is unacceptable and the perpetrators of that violence must be brought to justice."

While some students had behaved "disgracefully", it was clear that many of those committing acts of violence were "organised thugs", she told MPs.

More than 30 police officers were injured last Thursday as protesters hurled bottles, stones, paint, golf balls, snooker balls and flares and used metal crush barriers as weapons, said Mrs May.