Civil liberties groups are up in arms after it was revealed that millions of car journeys monitored using number plate identification are to be stored on a national database for five years.
Automatic number plate recognition (ANPR) is already used to record some 10 million journeys a day, but this figure is set to rise to 50 million.
The information will be collated at a new National ANPR Data Centre in Hendon, north London, for use by police.
While the original period for which the data was planned to be held was two years, the Home Office has confirmed that it was now being kept for five years.
The disclosure came after a freedom of information request by The Guardian. The paper has also obtained an ANPR road policing strategy document advising officers to "fully and strategically exploit" the car data gathered.
Simon Davies, director of Privacy International, said the database gave police "extraordinary powers of surveillance" that were "unnecessary and disproportionate".
He added: "This is possibly one of the most valuable reserves of data imaginable."
Copyright © PA Business 2008