More than 30 people were arrested after a big demonstration against education cuts and increased tuition fees ended in the occupation of the ruling Conservative Party's headquarters.
Windows were smashed, fire extinguishers were set off, and graffiti daubed on the walls of 30 Millbank in London.
Police were overwhelmed by the crowd outside the building.
The march had been organised by the National Union of Students (NUS) and the University and Colleges Union (UCU).
Sally Hunt, general secretary of UCU, told various papers: "The actions of a minority should not distract from today's message. The overwhelming majority of staff and students on the march came here to to send a clear and peaceful message to the politicians. The actions of a minority, out of 50,000 people, is regrettable."
On Tuesday evening in comments on The Workers United John Tymon called for the occupation of public buildings. Twelve hours later it was happening! Where next?
Maybe other Conservative offices around the UK could be occupied. Or the roads outside them blocked by protestors.