Let us start from the very obvious beginning and it is this: there was going to be considerable street violence yesterday and that was completely inevitable. In more than 20 years of watching domestic and international rioting, I think I have picked up a thing or two about reading these events.

Yesterday was markedly different from previous marches which I have been on concerning student fees. Even outside London University,  forming up, there were at least 200 youths at or near the front of the march already masked up.

The police too were much more in-your-face. At this stage still hard baseball caps on the heads, but riot helmets already hooked up to their belts.

Then, the march stopped almost as soon as it began. There were a series of short speeches from student union leaders and an  RMT union official. Over half an hour or so these speakers invited protesters to “bring down the government” and ” bring this country to a halt” and there were a number of references to what was felt to be over-aggressive policing.

The crowd, by the end of all this, was absolutely itching to get going and set off at a fast walking pace. That’s significant. There was urgency. Urgency to get to Parliament Square. Everywhere you stood you heard mobile phone and actual conversations setting out the prime need not to get caught in the inevitable police kettling operation. To break out. To keep the police on the run. I heard several conversations even late mrning saying that the thing to do was get up to the West End and hit the appropriate targets – Topshop was mentioned several times on Oxford Street.

I reported much of this by early afternoon. If I knew all this, surely the police did?

Within half a mile of marching we filmed the first police officer being dragged into the gutter, injured by protesters. Already hundreds were peeling off to run up any handy side street and keep the police on the hop – just as they had done on the previous march as soon as it reached the Aldwych area. So by Trafalgar Square sub-marches were pouring into the area from several different directions and the police were shouting at each other and running around to try and slow the march down and get some kind of handle on where people were going and why.

Of course the majority of marchers followed the agreed route up to Parliament Square and here is where everything broke down.

First, nobody had the slightest intention of continuing off the square, up Whitehall, to have a peaceful rally on the Embankment. Student stewards tried to ask people. There was no chance. As openly planned from the off, Parliament was to be the focus and that was that.

How anybody on the police or organisers’ side thought things would be different simply beggars belief. On the day of the vote the target was going to be Parliament, Parliament and Parliament.

So, could the police hold the line? No. As crowds poured in along the northern flank of the square, the plice lines failed. Hundreds broke through police line in the north-western corner where Great George Street meets the square. Within minutes the demo had possession of Parliament Square itself, for the first time since the British people were banned from it some years ago. And they sensed, this was a major achievement.

To get there, a degree of violence was essential, you cannot break through police lines without it. The police responded with batons. Deomstrators then threw any thing they could at the lines of riot police.

But now, instead of having the protest cordoned into one northern flank of the sqaure, the police had lost control of the square itself.

Now protesters could and did attack riot lines all along the eastern edge of the square in front of Parliament itself. They did so at the northeatern junction of the sqaure with Whitehall. And they did so along Broad Sanctuary alongside Westminster Abbey.

Because the police lost control of Parliament Square they now faced concerted violence on not one but at least five flash points. Not only that, for several hours no tight kettling operation was put in place.

This meant that protesters could sense where the kettle would be – Parliament Square – and had ample time and opportunity to escape, regroup and head up to the West End to make good on promises to attack the likes of Topshop.

That they got to the Royal car is currently being reported with general British media hysteria. In fact there is no security issue here except one blatant mistake.

It was obvious that groups of protesters were roaming the West End and had been for some time. All that had to happen was for Charles and Camilla to be told to have a quiet night in and forget the Palladium – unless of course they were keen to see what was afoot and insisted on making the journey. Not entirely impossible, but seemingly discounted in the currrent absurd hysteria surrounding a rather minor moment of violence an a day of rather widespread confrontation.