The mayhem in central London was as shocking as any in recent memory: protesters breaking down barriers and using them as weapons; windows smashed at the Treasury and the Supreme Court; a car carrying the heir to the throne attacked on Regent Street after straying into the path of roaming demonstrators.
And on the other side, police laying about them with truncheons; police horses charging the crowd, and a return of the hated "kettle", with protesters held for hours on Westminster Bridge. Even allowing for the selectivity of the camera, it is a minor miracle that more people were not seriously injured.
Granted, the Houses of Parliament remained secure. MPs were able to debate and vote on raising the cap on university tuition fees unhindered. If that was the central objective of the day's police operation, then, to that extent, it was achieved. The attendant damage – in all senses – however, was enormous, and it poses the same question that the last university-fee protests also raised. Is it really impossible for protesters to be able to exercise their right to be heard, while police meet their responsibility to keep public order – and do so without deploying the sort of deterrents, such as water cannon, that are used in many other countries?
We do not suggest this is easy. Provision for the tripling of university tuition fees raised impassioned opposition that went beyond today's students and their families. This tapped into a more general mood of public anger and anxiety about impending spending cuts. Clearly, too, there were groups of protesters on Thursday who were bent on provocation and violence.
But there was advance agreement between organisers and police that the march would take a particular route, on which police contingency plans were presumably predicated. The fact that this plan went awry so quickly, with protesters determined, and able, to reach Parliament Square, has to be accounted a major failure. Ditto the way even a small number of protesters were able to smash windows at nearby government buildings and run amok in the West End.
An operation involving almost 3,000 police officers – at corresponding cost to the public purse – was not capable of protecting highly symbolic public property. Nor is it sufficient to imply, as the Commissioner of the Metropolitan Police almost did yesterday, that protesters were pretty lucky that the Prince of Wales's armed security detail did not open fire. More truly alarming, from the perspective of the Prince's safety, was that his security detail seemed nowhere to be found.
The police will doubtless object that they are damned if they do and damned if they don't. The softer methods used against the first fees protest – in reaction, perhaps, to complaints about "kettling" at the 2009 G20 protest – culminated in the assault on Conservative Party headquarters. Policing of the second protest was tougher, but snow also reduced the numbers.
Protesters will be out again on Monday. The cause will be the abolition of education grants for older pupils from low-income families. The demonstrators are likely to be younger and even less cautious than those who spearheaded previous protests. The police will have to plan for a test at least as severe as the one they proved so unequal to this week.