ANPR stands for Automatic Number Plate Recognition. The UK has a network of ANPR cameras which can be found on most motorways and main roads, as well as at ports, petrol stations, and in a few cases entirely surrounding the centre of some cities or towns - a so-called 'ring of steel'.

I say a 'network' because although some ANPR cameras are stand-alone, most are connected to the National ANPR Data Centre in Hendon - conveniently close to the Police National Computer, which is also located there.

Incidentally, the majority of ANPR cameras which do not currently transmit numberplate data to the police are owned by Trafficmaster, and used to monitor traffic congestion. In the late 90s Denny worked for a company which made in-car navigation systems, and he knows from meetings with Trafficmaster that even then the police were trying to get access to the data from Trafficmaster's cameras. The company has always been resistant, allegedly for the reason that they don't want people hating and vandalising their cameras! In fact, they even deliberately designed their second-generation cameras not to read a full numberplate (they only read and store the central four characters), to reduce their potential usefulness to the police. It's quite an achievement that Trafficmaster have managed to hold out this long.

Even without Trafficmaster's cameras, the police have over ten thousand ANPR cameras providing numberplate information to them. Each day they store over 15 million readings in that central database, where they are retained for between 2 and 5 years. Some of the cameras also take photos of the driver and passengers in the vehicle - these are generally stored for shorter timeframes centrally, although local forces may still choose to store them for several years.

In June last year, the National ANPR Data Centre was storing 7.6 billion records. By March this year that had risen to over 11 billion records - an increase of 3 and a half billion records in 9 months, or about 5 billion per year - and accelerating.

Unregulated and undemocratic

All of this has taken place without any significant democratic process. ANPR has never been debated in Parliament or been subject to public consultation, and at present there is no legislation empowering the police to use it for blanket surveillance. In the opinions of some, including Privacy International and the Information Commissioner, this may render the current approach unlawful.

In 2006 the Surveillance Commissioner ordered a statutory framework regulating ANPR. In 2010, when this still had not taken place, the Home Secretary Theresa May said the system urgently needed statutory regulation.

Our current government has pledged to regulate CCTV and ANPR more closely, with measures being introduced in chapter 1 of their Protection of Freedoms Bill, due to come into force next year. However, there are concerns about the usefulness of the Bill in successfully regulating the use of ANPR - for example, it's limited to police/local authority use and doesn't cover private or government use; several principles in the Bill appear to be self-contradictory with no process described for resolving these conflicts; the proposed Statutory Code of Practice potentially conflicts with the Information Commissioner's code, again with no mechanism to resolve conflict; and the Surveillance Camera Commissioner's code carries no penalty if breached, rendering it effectively toothless.

Rings of steel

The first ANPR 'ring of steel' was put in place in London in the early 90s, in response to the ongoing IRA bombings at that time. It was part of a larger ring of steel which included road narrowings and closures (mostly using concrete blocks, rather than steel) and 'guard huts' where police could stop and inspect cars and their drivers on their way in and out of the area. The area in question was the financial district AKA the square mile - the rest of Londoners, of course, could take their chances with the bombs.

Nowadays the Met Police also have real-time access to the ANPR cameras used to run London's congestion charge zone, which gives them coverage of a wider area.

Other city centres which have been fully circled with ANPR include Manchester and Birmingham. Birmingham was in the news last year for a massive increase in their CCTV and ANPR network, called Project Champion. This was sold to councillors as a crime prevention, safety in your community initiative, but turned out to be funded out of the anti-terrorism budget - which is quite shocking when you realise that the scheme formed mini rings of steel around two Muslim neighbourhoods. 169 cameras were installed including 40 covert cameras hidden in trees and walls, in order to track residents entering or leaving the area.

Worse, councillors including Salma Yaqoob, a Respect candidate active in Muslim rights, challenged police before the initiative on the grounds that the scheme would unfairly target Muslim residents. West Midlands police dismissed their concerns and refused to reveal the source of the project's funding. Police also told councillors that the cameras would not be installed without "a full consultation and assessment process" which never in fact took place.

Once this had been exposed, the cameras were mostly decommissioned and are now likely to be repurposed down here to London in time for the 2012 Olympics. (Brilliant, cheers for that.)

The Olympics are being used to justify increased spending on ANPR, as part of the official police ANPR strategy for 2012. In fact six additional ANPR camera sites, a mixture of fixed and mobile, are already in place and operational in ... well, not Stratford bizarrely, but as far afield as Dorset and South Yorkshire as part of this strategy. That's ten months early - and it would be perfectly consistent with police behaviour so far if these extra sites just happened to stay in place after the games as well.

Data-sharing and data-mining

Police are currently receiving 15 million records a day from the ANPR camera network. The system is designed to handle up to 50 million a day, so obviously they've still got some ambitions to expand the scale of the network. Those billions of records they're holding enable them to do all kinds of revealing data-mining. The example they like to give is that if a numberplate appears in two different parts of the country with an impossibly short time gap between them, then they know there's a car running around with a cloned numberplate (or, presumably, that one of their cameras is a bit screwy, but obviously technology is perfect, so I'm sure that couldn't possibly happen).

An example they may not care to give is that officers from Forward Intelligence Teams will record the numberplates of any vehicles they see in the vicinity of a political protest and consider 'interesting' (say, has 'stop the war' stickers in the window or similar), and mark these as 'vehicles of interest'. Bear in mind that police spokespeople claim that ANPR data won't be accessed unless the vehicle registration is linked to "crime, disorder or an unsafe vehicle".

One instance of this sort of 'extracurricular' data mining was the case of John Catt, an 84 year old pensioner, who with his daughter Linda was stopped and searched last year under Section 44 of the Terrorism Act. Police performed this search because a marker had been placed against their vehicle in the police database as a result of them being near an EDO anti-war demo in Brighton, which was triggered when their vehicle was photographed by an ANPR camera. They hadn't been involved in any criminal activity, merely parked near to (and correctly suspected to be involved with) a peaceful political demonstration.

This represents a pretty broad definition of "disorder" - and it's used to justify any future records of that numberplate being held for the full 5 years instead of 2, subsequent stops and searches and other harassment.

There have also been some concerns relating to misuse of the data held on these government databases for corporate purposes. In 2009 the parts of the DVLA database linking registration plates to vehicle makes and models was sold to Castrol, who used that data plus their own ANPR cameras and large roadside screens to produce tailor-made adverts telling people driving past which type of Castrol oil would best suit their car's engine. There is a specific rule in place against use of the database for marketing purposes, but it didn't seem to stop anyone involved from sharing and using the data in this way regardless.

ANPR is big business. Increasingly sophisticated camera and data analysis equipment is the next growth product to take off in the UK, and is already starting to be the biggest potential earner for installation companies. Camera providers represent a large economy with a vested interest in maintaining a market for this burgeoning industry - and there's plenty of scope for the industry to deliver hype and misinformation to increase the demand for their products, as well as buying data and using it for commercial purposes.

On the bright side, the data they're buying might not be that much use to them anyway. A 2004 national report put the accuracy of the DVLA lookups at only 40% due to errors in the vehicle and driver databases. By the end of 2009 this had improved to 88% accuracy in the vehicle licensing database and 74% in the driver database, but that's still up to 1 in 4 inaccurate lookups.

Freedom of information

The police are a bit cagey about revealing the locations of their shiny new toys, despite the fact that for the most part they're bloody great cameras by the side of the road which are visually conspicuous to anyone doing a little research on the ground. Anyone who wants to know where the cameras are - criminal or otherwise - can therefore easily avoid them unless it's part of an actual ring of steel. Meanwhile, hidden camera locations are relying on the Security through Obscurity method - not very sustainable.

Last year the Guardian's 'government computing' section put in a Freedom of Information request to discover the location of cameras being installed in Devon and Cornwall for an article about ANPR, but the police there said "no". So, the Guardian appealed to the Information Commissioner's Office, who considered the matter for a year and a day (not being poetical, that's how long it took them to make a decision), before deciding that the police were within their rights to say no. The Guardian appealed that decision to the First Tier Tribunal for Information Rights, who overturned the ICO decision, saying neither the ICO nor the police had paid sufficient attention the public interest angle of reporting on this sort of large-scale surveillance network. They ordered the police to reveal the camera locations within the next 35 days.

That was a few months ago. You will be shocked and amazed to hear that the police are appealing against that decision, and so the camera locations have still not been disclosed.

One way for the police to get around the problem of revealing camera locations is to use mobile cameras instead. Shropshire, for instance, have just completed a trial of car-mounted ANPR cameras with GPS installed.

Mobile cameras have also been used in the past by Kent police. Significantly, they used them when local councils refused to give Kent police permission to install fixed cameras to monitor the roads leading to Kingsnorth prior to the Climate Camp there.

The police operation around that Climate Camp was subsequently heavily criticised for excessive use of surveillance, stop and search, and other disruptive tactics including the playing of loud music to cause sleep deprivation among those attending the event - usually a tactic associated with battlefields and prisoner of war camps. The police have been successfully taken to court by several protestors as a result of their tactics, and the way lies open for thousands of further cases based on this success.

Proportionality and justification

In Hertfordshire, Royston is now being treated to its very own ring of steel. Entirely coincidentally, the Chief Constable of Hertfordshire Constabulary was the ACPO national lead on ANPR until quite recently. (ACPO is the Association of Chief Police Officers, a for-profit company set up to represent the interets of senior police officers to all levels of government.)

Hertfordshire police claim that being on the borders of Hertfordshire and Cambridgeshire makes Royston a place of some considerable strategic importance for this kind of mass surveillance. Given the huge problem with illegal border-crossings between middle-England counties, one wonders why they haven't also set up barbed-wire fences and regular patrols with dogs and machine guns, but I'm sure they'll get around to it soon and then we can all sleep safely at night once more.

Quite aside from concerns about proportionality, all this is very expensive, and arguably does not offer good value for money. Police forces claim that ANPR systems save them personnel expenses, and weigh the cost of the technology against the funds recovered through crime investigations. Councils can also earn money via penalty fees and charges (for e.g. illegal parking or not wearing seatbelts) which are then also set against the cost of the systems by way of justification.

However it is hard to weigh the social cost of ANPR in terms of the threat it represents to privacy and freedom, against the social value in terms of the number of crimes solved - at least in part because clear numbers on the latter is hard to obtain.

One of the things that we've noticed a lot in reporting of policing lately is that police will use 'softer' stats when they're trying to hype of their less credible policies. So for instance, they'll talk about how many people they arrested at a protest rather than how many they charged, and in fact neither number is a particularly hard stat - how many are convicted is the really relevant number, but you rarely hear that reported.

With ANPR this seems to have gone even further, and you'll frequently see police spokespeople talking about how many 'hits' the cameras get, with no reference to the accuracy, relevance or usefulness of these hits, or how many of them lead to a successful prosecution. Getting lots of hits is great if you're running a website, but it's pretty poor justification for a nationwide surveillance network.

With many local communities actively clubbing together to request new ANPR installations in attempts to reduce crime, we need to wake up and perceive the threat to our privacy and freedom of movement which the growing use of this technology represents. On a national level, and in what appears to be deliberate strategy, UK police are not just using these cameras to control speeding or badly parked cars, but political targets too.