Protesters angered by proposals to increase university tuition fees brought violence and chaos to the streets once again last night.
Tens of thousands of students were joined by lecturers and parents during a national day of action against the controversial changes.
Westminster bore the brunt of lawlessness a fortnight after the Millbank riot as two police officers and 11 people were injured.
At least 15 protesters were arrested for offences including violent disorder, theft and criminal damage as barriers were thrown and fires lit in the street.
The clashes centred around a stranded police van that was ransacked and looted a short distance from the entrance to Downing Street.
Police were forced to “kettle” hundreds of protesters for around four hours a short distance from the Houses of Parliament.
The tactic was widely criticised after around 5,000 people were penned in outside the Bank of England during the G20 protests last year.
Thousands also joined protest marches in Manchester, Liverpool and Brighton as pupils walked out of school in Winchester, Cambridge, Leeds and London.
The protests were dubbed Day X, with parents, teachers and trade unionists invited to join students at rallies organised by the Education Activist Network and Youth Fight For Jobs.