SECRET police surveillance cameras in Devon and Cornwall read and stored 64 million vehicle number plates last year.

The staggering figures mark a near-1,000 per cent increase compared to 2007 and equate to 80 records a year for each of the 800,000 registered vehicles in the Westcountry.

Records – even for innocent motorists – are kept on a police database for a minimum of two years. Westcountry MPs complained that the network of fixed roadside cameras had been expanded “by stealth”.

Devon and Cornwall Police said the cameras were essential in the fight against crime – denying criminals the use of the roads and catching a range of offenders from drug dealers to uninsured drivers.

The force has refused to say how many automatic number plate recognition (ANPR) cameras it operates or where they are installed, for operational reasons. However, they are known to monitor the region’s main routes – the A30, A38 and M5 – as well as other strategic locations such as ports and airports. There are up to 60 ANPR systems nationally that operate through CCTV.

South East Cornwall MP Colin Breed said he was “astonished” by the latest figures and claimed that the ANPR system had been expanded “by stealth”.

“It is providing clear surveillance in what we fondly believe is a free country,” said the Lib-Dem MP. “While I understand why the police want to utilise this technology, I think they need to make their case to the public, if it is to be publicly accepted. People need to understand why they are under surveillance if they are to be reassured that it is for their benefit.”

A Freedom of Information Act request has shown that Devon and Cornwall Police captured 63.99 million images in 2008, the equivalent of two every second and a near 10-fold increase on the 6.7 million records created in 2007.

Hits on so-called “vehicles of interest” – ranging from those with no insurance to those linked to known criminals – rose from 157,500 in 2007 to 1.16 million last year.

Geoffrey Cox, Conservative MP for Torridge and West Devon, said the cameras were part of an “invisible network of surveillance” that had been constructed over the past 10 years.

“It is a surveillance state in which people are being monitored and observed morning, noon and night,” he said.  “It is a Big Brother state which assumes and suspects that everyone, at any time, might commit an offence, and so gathers evidence against you in advance.”

Mr Cox said there needed to be a public debate about police use of the cameras. He added: “It is an unsettling symptom of something that has grown up without people’s recognition, understanding and assent.”

Nationally, 26 out of 43 forces were able to supply comparable data. It revealed that 1.82 billion numbers plates were read and stored last year. The combined figure for all forces is like to be in excess of 2.5 billion.

Figures released showed there were 758 million records created in 2007. There are only 34 million registered vehicles in the UK.

The highest number of records were created by the Metropolitan Police with 342.8 million, followed by West Midlands Police with 267.6 million. Avon and Somerset logged 21.6 million registrations last year and Dorset 16.6 million.

Isabella Sankey, policy director at Liberty, said: “ANPR allows the tracking of car users’ movements. We have no problem with it being used to locate vehicles whose owners the police firmly suspect of having committed a driving offence, but it shouldn’t be used as a tool of mass surveillance.”

Devon and Cornwall Police Deputy Chief Constable Tony Melville said the force had decided to invest in ANPR technology three years ago after evidence from pilot projects elsewhere in the country. He stressed that the necessary safeguards were in place to manage the information and that the technology was delivering results.

“In an area like Devon and Cornwall, criminals need to move around to commit their crime, whether that’s stealing property or dealing drugs. Denying them free access to our road system, being able, on an intelligence-led basis, to know, where they are, is an invaluable asset for us.”

Mr Melville said he believed that the cameras were resulting in more arrests, more property being recovered and more drugs being seized.

In 2008/09, the cameras were directly responsible for recovering more than 30 stolen vehicles, along with offenders, and  seizure of more than £80,000 cash. So far this year, they had been helped detect on average 15 crimes a month.

Mr Melville added that since its introduction, more than 2,000 vehicles had been seized from uninsured drivers. “Every one of those vehicles had the potential to injure someone for life.”

He believed that the public knew about ANPR and that information was compared against databases.

He hoped the public would understand that the force did not want information about its ANPR tactics to be widely known because of the risk of jeopardising its effectiveness. On that basis, he was “not overly concerned that there hasn’t been a wide-ranging debate about tactics”.

Mr Melville went on: “Yes, this is compiling details of vehicles that are using the roads and their number plates. However, we only access that information if it is relevant to a crime.

“For most people going about their everyday business, it is not something that they need to be concerned about. We don’t go and look at data to see what people are doing unless there’s a justifiable case for doing so.

“I recognise that people may feel uncomfortable about CCTV and shops where they have cameras behind the counters filming customers. You can’t use the Internet now without companies collating information on your shopping preferences and the sites you have looked at.

“ANPR is much more discerning than some of the other things that we have in society at the moment,” he added.