The details of thousands of journeys made by motorists every day are being stored for up to two years by police.
Motorists are being watched and tracked by dozens of cameras, which record the vehicles’ number plates as they travel through Portsmouth.
Hampshire Constabulary is building up a vast database of round-the-clock information on the comings and goings of visitors and residents from the data recorded by automatic number plate recognition (ANPR) cameras.
The information is passed on to police by Portsmouth City Council — one of a few local authorities across the country with the ability to manage and read ANPR data on its large network of 15,000 cameras.
The number of CCTV cameras works out at one for every 12 people who live in the city — although a city council source said only 170 cameras are actually placed in public areas like Guildhall Square.
Police argue the ANPR cameras — designed to read car number plates to see whether vehicles are insured, have an MOT certificate or road tax — are essential for catching criminals and terrorists.
However civil liberty campaigners are concerned that all trips, no matter how mundane, are being recorded and stored for two years.
Isabella Sankey, director of policy for civil liberties group Liberty, said: ‘The road to massive scale real-time surveillance is paved with good intentions.
‘We have no problem with ANPR being used to locate vehicles whose owners the police firmly suspect of having committed an offence but it shouldn’t be used as a tool of mass surveillance.’
Hampshire Constabulary, like all police forces, see the cameras as an essential part of their surveillance of more serious criminals.
Spokesman Tim Feltham said: ‘Automatic Number Plate Recognition is an extremely useful police tool which can be used to reduce crime, detect offences and combat terrorist activity.
‘Hampshire Constabulary uses the system in a lawful and proportionate way and in line with national policies on the storage and retention of data.’
Ray Stead, the CCTV manager for Portsmouth City Council, said: ‘ANPR is linked to our cameras but it is a transparent system, which means we do not do anything with the information.
‘It is all sent back to the police. We do not do anything with it and we do not see it.’
HOME SECRETARY’S CLIMBDOWN
Just this week, Home secretary Jacqui Smith climbed down on government plans for giant database tracking all e-mails, phone calls and internet activity, saying a central store of electronic data was an ‘extreme’ solution and would have undermined privacy.
Instead, records of every electronic connection made by Britons will be held by private companies at a cost of around £2bn.
Internet and telephone firms will be asked to collect and store vast amounts of information on who we are speaking to, what websites we are visiting and who we are exchanging e-mails with.
Communications data — which excludes the content of messages and calls — will be held for at least a year so it can be accessed by government agencies such as the police, security services and other bodies.