According to their annual report, our police are currently experimenting with Automatic number plate recognition (ANPR) technology. For those who don't know, this is basically hooking OCR up to a camera to automatically read car licence plates. The data - including time, location, and of course the car registration details - is either used to locate a vehicle in real-time, or databased for later mining.

Even at a small scale, this presents obvious privacy concerns. The police are parking these cameras by the side of the road, and recording the details of every vehicle that goes past. According to their ANPR manual [PDF], they keep it for at least six months. Even at the trial level, there are strong questions about the proportionality of this (the police ar ebasically databasing people's movements, regardless of guilt or innocence and without any probably cause, simply in the hope that it will prove useful later). And those concerns grow stronger with every camera added. In the UK, where this technology is widely used and cameras are placed at all strategic intersections, police can basically track you everywhere you go in a car - and they do, for everyone, all the time. Its basically an automated Big Brother for cars.

So you'd think that with such strong privacy issues, the police would have consulted the Privacy Commissioner on the deployment an use of this technology, right? Wrong:

A police spokesman said the force did not intend to consult the Privacy Commission because it had its own legal experts to ensure the manual was consistent with privacy law and other legal requirements.

Those "legal experts" would be the ones who advised that it was fine to trespass on private property to place hidden cameras in the Urewera trial, or to just take everything not nailed down and give it to the FBI in the DotCom case. But quite apart from the poor quality of their advice, they're hardly experts in privacy law, and will inevitably see things through a police lens of "nothing to hide, nothing to fear". And that's just not acceptable in a democracy.

But we can't say the police are absolutely blind to the privacy concerns around this technology:

The draft manual for covering the cameras lists examples of improper use, including tracking people where there was no suspected unlawful activity. It gave the example of an officer seeing someone they want to meet socially and noting their licence plate so they can check the database for that person's movements and then try and bump into them.

I'm sure that advice will be a great condolence when police officers abuse these databases in exactly that manner.

This technology will allow police to track everyone everywhere they go. And that is fundamentally incompatible with our nature as a free and democratic society. We should not allow the police to implement it by stealth without a proper public debate.