BRITISH police have warned that months of public disorder lie ahead for London as looming austerity measures and student demonstrations appear also to be attracting groups intent on violence - from street gangs to anarchist organisations.

The streets of the capital erupted once again on Thursday as students, infuriated by rising university tuition fees, lit fires, turned on police vans and defaced monuments. The protest culminated in a mob attacking a Rolls-Royce bearing Prince Charles and his wife, Camilla. A window was smashed and paint thrown at the vehicle as the couple made their way to a central-London theatre for the annual Royal Variety Performance.

Quite a performance: Protesters jump off a burning park bench during the riots. Credit:Reuters

A witness at the scene described the royal vehicle turning up Regent Street and heading into a crowd of protesters massed across the street, some of them smashing shop windows and setting fires. ''I thought it was mad of them to head up Regent Street, because there were thousands of protesters at the top of the street, and the car was heading straight into them,'' the man told the BBC.

It was the third round of demonstrations in London in a month and left 10 police officers and 43 protesters injured and led to 26 arrests. Prince Charles and Camilla were shaken but unhurt.