UK Police have been granted the right to continue to keep secret the locations of controversial automatic number plate recognition (ANPR) cameras, after winning a freedom of information tribunal - even as they admit that criminals know the whereabouts of some of the spycams.
However, as reported by the Guardian, which has been campaigning for the police to disclose the information for the past three years, there are glitches in the ANPR system that uses thousands of fixed and mobile cameras to track motorists' movements in England and Wales.
According to the newspaper, police now store records on the whereabouts of 16 million vehicles.
But the police chief in charge of the new network, which according to police helps them snare low-rent criminals and high-profile terrorists, has confessed that there remains "large gaps in coverage in various parts of the country".
A central database held in Hendon, north London, holds more than 7 billion records from images transmitted to that location since ANPR was first set up in 2006, the Guardian reported.
As of July 2010, the Home Office said that the same database held more records than today's figure - standing back then at some 7.6 billion individual files. Which presumably means that the information isn't retained for all time.
John Dean, who heads up the ANPR system for The Association of Chief Police Officers (ACPO), told the Graun that there were weaknesses in how the information was gathered.
"This network of ANPR cameras has been established at local level to reflect the needs of local policing priorities. There has therefore been no national deployment plan, and this has resulted in significant gaps of coverage throughout the country," he said.
"The disclosure of the locations of existing ANPR cameras could therefore put some areas at greater risk, the criminals becoming aware of these gaps of coverage."
During the years that ANPR has been in operation, the police have claimed some 50,000 arrests.
But, during the tribunal, various cops talked of tactics employed by crims to evade detection from the spycams.
DS Neil Winterbourne, who is the Met's counter-terrorism specialist overseeing the ANPR system in London, said that "a particular driving style" could be tapped by those wishing to avoid capture by the police.
"I will not go into the conduct of such tactics herein, but it is true to say that a properly trained driver can adopt a particular driving style that will greatly reduce the chance of the vehicle being detected by ANPR," he said.
"These tactics are only effective in the short term, when in close proximity to a camera, and it would be impracticable for anyone to permanently drive around in such a fashion."*
Winterbourne also told the tribunal, according to the Guardian report, that there were various ways in which a number plate could be modified "to reduce the chances of detection by ANPR".
Upon human inspection of such vehicles, cops can normally spot when a legitimate number plate has been fiddled with. But clearly, the technology used in the ANPR system still retains a few "blind spots".
Other police witnesses at the tribunal noted that some of the spycams had been damaged by criminals to render them "inoperative".
The vast Hendon database, meanwhile, can be analysed by police for any purpose, whether they are tracking persons of interest or otherwise... ®
*It should be noted that an ANPR camera must normally be triggered in some fashion so as to snap imagery of a car during a narrow time window when it can capture the entire number plate at a decent resolution. Many systems, especially those on roads or motorways where there's no scope to fit an induction loop or beam barrier, are triggered by detectors which measure a vehicle's speed in a different "box" of road than the "box" in which it is then to be imaged, so that constant aggressive changes in speed could fool the trigger into activating the camera at the wrong moment. - Ed