The control centre of a national network of roadside 'spy cameras' that will be able to track the movements of every motorist, around the clock, is to be located in Hendon.

The national operation will be overseen from an undisclosed location, which will be able to process as many as 50 million number plates a day by the end of 2006.

Using a system known as automatic number plate recognition (ANPR), similar to that being used for the congestion charge, the cameras will allow officers from intercept teams to crack down on uninsured drivers, road tax evaders and stolen cars, and it will eventually be used to assist with more serious crimes.

The hope is to see a national network of cameras installed at supermarkets and petrol stations where there are existing CCTV networks and at every 400 metres of motorway.

Investigating officers will eventually be able to access the information from computers at anytime, and from almost anywhere in the UK, although they will require clearance from senior managers.

John Dean, the Association of Police Officer's national ANPR co-ordinator, said: "The ANPR will be able to read data from cameras and can be accessed by 43 police centres in the UK.

"It will read the plate and check it against records.

"The system will tell the officers whether the car is stolen.

"It will also help us to undertake intelligence-led policing. If there's a rape scene, we can pinpoint the car and the registered driver caught in the area.

"It would help us investigate stolen vehicles, drugs, firearms, property, credit card theft and terrorism too. We can locate those with no MOT and no insurance most of the time they are involved in criminal activity."

The cameras are not only linked to the police national computer, but also to the Driver and Vehicle Licensing Agency database, which allows officers to identify vehicles that are not registered or taxed.

Details of any vehicle passing a camera will be stored in a database for at least two years even if the owner has not committed an offence.