Civil liberties group Big Brother Watch says introducing dozens of new police cameras across Merseyside has the potential to “seriously undermine your privacy.”
Merseyside Police’s new Matrix Serious Organised Crime unit is expanding its use of Automatic Number Plate Recognition (ANPR) technology by setting up 50 new camera sites across the county.
Nick Pickles, director of Big Brother Watch, said: “ANPR cameras can track every journey every single vehicle makes, every hour of the day.
“It has the potential to build up a picture of your whole life and seriously undermine your privacy.
“Merseyside Police should be explaining clearly and transparently how they intend to use this technology, what data they will be collecting and how long they will be storing it.”
Mr Pickles added: “The only sure way to protect people’s privacy is to not collect data.
“If the police are only checking against a known list of suspect vehicles that is proportionate, but it is not right for them to be logging every car’s movements and storing that data for a prolonged period of time.”
In a statement announcing the new cameras yesterday, Chief Superintendent Mark Harrision said: "I am sure the public will see this as a good thing and I would like to assure law-abiding people that they have nothing to fear from these cameras.
"They do not monitor speed, they simply check the number plate against a database.
"It is the criminals using our road networks to carry out crime that should really be worried."
The ANPR system works by automatically reading the registration of every vehicle that passes through it.
The registration is then checked against a range of databases, including the Police National Computer, Driver and Vehicle Licensing Agency and local police intelligence systems.
Officers can then instantly tell if the vehicle is of interest to police - for instance if it has being stolen or been used in a recent crime - and then take necessary action.
Police stopped 541 vehicles across Merseyside on Wednesday following an ANPR operation, with 20 drivers arrested for a range of offences.