Automatic number plate recognition (ANPR) cameras photograph and read vehicle number plates and are already in operation. Local authorities and police have expanded the number of cameras and a national database for the images captured by the cameras will go live at the end of the year.
The Guardian newspaper obtained Home Office correspondence which says that data gathered by cameras and stored in the database will be kept for up to five years.
Privacy International has complained to the Information Commissioner's Office (ICO) about the retention of the information for that period.
The ICO is responsible for monitoring compliance with the Data Protection Act (DPA), which says that data should not be stored for longer than necessary to fulfil the purposes for which it was gathered.
"The ICO recognises that automatic number plate recognition can assist in the detection and prevention of crime, however it is important that where large amounts of personal information are collected and retained adequate safeguards are in place to protect individuals’ privacy," said an ICO statement.
"The principles of the Data Protection Act clearly state that personal information should only be stored for as long as is necessary," it said. "Any prolonged retention would need to be clearly justified based on continuing value not on the mere chance it may come in useful. We take all complaints seriously and will be contacting the relevant organisations to discuss proposed data retention periods.”
ANPR cameras are also used in London to track compliance with that city's congestion charges. Last year the Metropolitan Police were granted an exemption from the Data Protection Act by Home Secretary Jacqui Smith.
That exemption allowed camera operator Transport for London to pass on real-time data from the cameras to police and allowed police to use the data irrespective of DPA restrictions as long as the use was for the protection of national security.
In 2006 the Chief Surveillance Commissioner Sir Andrew Leggatt warned that ANPR cameras may qualify as covert surveillance and be illegal. He said in his annual report that unless the legal status of the surveillance carried out by the cameras was clarified prosecutions depending on ANPR evidence could fail.
"The unanimous view of the Commissioners is that the existing legislation is not apt to deal with the fundamental problems to which the deployment of ANPR cameras gives rise," he wrote in his report to the Prime Minister and to Scottish Ministers. "The Commissioners are of the view that legislation is likely to be required to establish a satisfactory framework to allow for the latest technological advances," he wrote.