Guido was outside CCHQ on Millbank late yesterday afternoon to see the action for himself, the fires were burning, a couple of thousand demonstrators were there, the outnumbered police were struggling to regain control.

The crowd was mainly made up of middle-class students with a couple of hundred of youths clearly up for trouble, masked and tooled up. Many of the protagonists were wearing official NUS hi-vis tunics and had loud-hailers, they were not calling on students to disperse or refrain from violence, they were in the thick of it. Officially the NUS is condemning the violence to the media, but that line was not taken on the ground. NUS activists were revelling in the moment. Look at the video evidence and you can see many of the rioters are in official NUS garb.

We’ll hear the speeches from the NUS leaders and others deploring the violence, but the reality was that most of the NUS student members found this all thoroughly exciting. The air was rich with the smell of weed and adrenaline, the 2,000 or so protestors outside 30 Millbank cheered the most aggressive protestors and booed the police resisting them.

The NUS marketed this march as a “Demo-lition” and thousands of their members took them at their word by attempting to demolish the Tory HQ. Worse than the demolition of property was the threat to life – yobs who smashed their way on to the roof tossed from the top of the office block a fire extinguisher – which narrowly missed the police targeted below.

If that had hit a policeman or protester below their life would have been extinguished.

The NUS leadership deliberately chose to march students past CCHQ to rally nearby outside the Tate. Why?

Demonstrations of this size usually rally at Trafalgar Square or in Jubilee Gardens on the Southbank. Before yesterday the NUS leader Aaron Porter was telling students they needed to be not just on “the streets of London” but “inside the rooms where the deals will be made”. The protesters took him at his word and managed to get inside the governing party’s headquarters, the buck stops with Porter and he should accept ultimate responsibility for inciting this riot. His members could have killed a copper or one of their own yesterday…

UPDATE: Both Dizzy and Tory Bear think Aaron Porter is in trouble. LBC dip an oar in too.