As you may know, we're big fans of CCTV in the UK. At the last count there was around 6 million CCTV cameras in the UK, or about one for every ten people living here. Most of these cameras are passive: they don't actually do anything, except for constantly recording to a tape or hard drive.

The big exception is the UK's nationwide automatic number plate recognition (ANPR) system. Here, in addition to storing the data on hard drives, number plates are actively interrogated and matched against a database of missing vehicles and wanted people.

The UK's police and intelligence agencies probably have their own networks that can provide real-time matching, and perhaps also access to other private and public CCTV networks, but that information is obviously hard to come by. Most recently, though, the Metropolitan Police asked for access to Transport for London's ANPR network so that it can carry out real-time facial recognition on all motorists entering London.

Which brings us neatly onto today's interesting bit of news. Facewatch is a system that lets retailers, publicans, and restaurateurs easily share private CCTV footage with the police and other Facewatch users. In theory, Facewatch lets you easily report shoplifters to the police, and to share the faces of generally unpleasant clients/drunks/etc with other Facewatch users. The BBC reports that Facewatch is currently used at around 10,000 premises. The Facewatch website is full of positive testimonials from shop owners and police forces alike; it does seem to work as intended.

Now, however, Facewatch has been updated so that it can be integrated with real-time face recognition systems, such as NEC's NeoFace. Where previously a member of staff had to keep an eye out for people on the crowdsourced Facewatch watch list, now the system can automatically tell you if someone on the watch list has just entered the premises. A member of staff can then keep an eye on that person, or ask them politely (or not) to leave.

Pre-crime

In the film Minority Report, people are rounded up by the Precrime police agency before they actually commit the crime. In the movie this pre-crime information is provided by "pre-cognition" savants floating in a goopy nutrient bath (pictured top) who can apparently see the future.

Replace those gibbering pre-cog mutants with Facewatch, and you pretty much have the same thing: a system that automatically tars people with a criminal brush, irrespective of dozens of important variables.

Facewatch lets you share "subjects of interest" with other Facewatch users even if they haven't been convicted. If you look at the shop owner in a funny way, or ask for the service charge to be removed from your bill, you might find yourself added to the "subject of interest" list.

Or what if you have been convicted, but have since come out of the criminal justice system a reformed person? Or what if you were convicted of some completely unrelated crime, but still find yourself stalked by a security guard every time you visit Tesco? Or what if you ended up on the watch list because you walked past a McDonald's during a democratic protest against the government or police, and then find yourself ushered out of every shop, restaurant, and pub you visit henceforth?

Pre-crime is potentially an awesome idea with the right safeguards, but to put that kind of power in the hands of private citizens and without significant oversight and code review is quite insane and open to egregious abuse.

The creator of Facewatch, Simon Gordon, told the BBC that the effectiveness of face recognition systems is increasing, while the price of such systems is falling rapidly. "Probably by the end of next year, it will be almost like having a mobile phone," he said. Jolly good.