Today’s announcement that PC Simon Harwood will face prosecution for the manslaughter of Ian Tomlinson at the G20 protests is welcome. I and many others will wish to see Ian Tomlinson’s family get justice for their father, step-father and husband. It is only right that there should be justice for Ian Tomlinson.

But Simon Harwood was not acting alone. He acted in a way that most people I know who have been on a protest would think is entirely characteristic of the Metropolitan Police’s Territorial Support Groups. It is also characteristic of the Metropolitan Police’s approach to policing protests. Before the G20 protests the response of senior commanders when asked about potential violence said that they were “up for it.” This is a well know vernacular term indicating they were keen for a fight. I remember very clearly saying to a colleague on the day of the G20 protest that if the police went on attacking protestors, sooner or later someone would be killed. And so, sadly, it was.

Satirist Newton Emerson once said that Ian Paisley’s approach to Northern Irish politics followed a three step process. First predict trouble. Second, cause trouble. And third say “I told you so.” This is seems to me to be exactly the approach the Metropolitan Police have taken to policing protests.

This process is aided by the dependence of the mainstream media on the police. The media rely on police for a very substantial part of the media coverage. It only takes a quick glance at the papers to see how important crime stories are to the media. This means that journalists are quick to accept the word of police press officers. And those press officers are often fed information that is intended to mislead the media when things go wrong.

The Metropolitan Police shot Jean Charles de Menezes dead in cold blood. Despite being Brazilian, they thought he was an Arab. But the media were told that de Menezes was behaving extremely erratically. They said he was wearing a heavy coat on a warm day and had jumped barriers when neither of these allegations was anything close to the truth. The media faithfully reprinted this and it was only later that the truth emerged.

At every protest there is a process of building expectation of trouble. Commanders brief the press on the threat of violence. They talk up the threat of trouble. On the day of the protest the police will use the agreed route to set up “kettles” for the protestors. Once in a kettle protestors are held for a number of hours, refused food and drink, or access to toilets. Those at the outer edges of the kettle are beaten with police truncheons. The result is a frustrated, battered crowd likely to retaliate to police aggression.

And this gives the police a convenient set of images – angry protestors hitting back at the police violence. By using their symbiotic relationship with the mainstream media the police it allows people to conclude that the police were forced to use violence to contain or subdue protestors.

The process of “kettling” is itself pretty futile. The police claim that it allows them to contain a protest. The effect is to ensure that protestors are nervous and skittish. They avoid agreed routes where police will hold them for hours at a time. The Day X student protests was marked by protestors frenetically running all over central London trying to avoid “kettles.” It’s clear to anyone that “kettling” is not a tactic that delivers better public order. Instead it makes it more difficult to police protests.

As a response to protestors avoiding “kettles” the police have sent groups of officers to roam the streets. Some like Simon Harwood behave in an aggressive and provocative manner. Harwood had already been thrown out of the police for violent behaviour but was let back in. This reflects how seriously the Metropolitan Police take violent behaviour amongst its officers.

In most circumstances they have gotten away with having violent officers, because until recently most people didn’t carry a video camera around with them. It was only because a member of the public had a phone with a video camera on it that there was an inquiry into Ian Tomlinson’s death. It was inevitable that at some point a member of the public would be seriously hurt by these squadrons of pumped up police, but unlike before there would be video evidence of what happened.

Why do they do this? It’s not really clear. It may be that they are under orders from the Home Office. It may be that they just like a fight. Or it may be that this is a strategy to prevent protest. Whatever the reason, it is important that Ian Tomlinson’s death marks a turning point in the policing of protests by the Metropolitan Police. Because if we go on as we have been his death won’t be the last at the hands of the police. This is not a rogue individual. It’s a systemic problem. The Home Office and the senior commanders in the Metropolitan Police must recognise this and ensure that police tactics and strategy change fundamentally.