But are they also, as the Met Commissioner noted, a harbinger of something else: namely, a return to a late 1960s, Continental-style protest, which will encourage other groups - from Tube drivers to Tamils - to use sit-ins, strikes and ultimately street-based violence as a political tool.
The NUS rejects that their tactics are associated with violence, knowing it will turn the majority of English people against them. Blame is heaped on small groups of agitators. Anthony Barnett argues that unlike in the 1960s, "the relationship to violence is also much better, as shown by the spontaneous revulsion of the demonstrators against throwing the fire extinguisher at Millbank."
I'm not so sure. I see a festival-type atmosphere degenerate amid agitation. After a few hous of tension, things become more permissive: it is seen as legitimate to vandalise private property, terrorise citizens and attack the police.
It is, of course, hard to imagine today's student protesters going on to form a Rote Armee Fraktion, as their delusional predecessors did. But at the same time I have not seen the kind of "revulsion" over violence others see. Sunny Hundal over on Liberal Conspiracy seems more representative when he minimises the violence: "So let’s stop self-flagellating about the absolutely tiny minority of protesters who threw a few things yesterday. There are bigger issues and policies that the coalition should be apologising for."
You would have to be deaf not to hear an echo from the left-wing terrorists of the past. Today's protesters also harbour some of the illiberal instincts of their forbears - their self-righteous indignation over the Liberal Democrats is spilling into a feeling that the democratically-elected Coalition government is illegitimate. And that is exactly the sentiment which in the Germany of the late 1960s led from Rudi Dutschke's rhetoric to a more violent set of actions.