The system uses roadside cameras that take a snapshot of every plate that passes and feed the data to a regional hub.

This information is then passed to the central data centre and can be accessed by authorised police officers via a web browser.

"It will revolutionise policing," said John Dean, national co-ordinator of the ANPR system. "Our aim is to deny criminals the use of the roads."

The cameras can track 3,600 individual licence plates per hour and, since the size and shape of the lettering is usually standardised, the accuracy of the data is 99.8 per cent, according to the system's builder Anite Group.

The system has already been used in trials and provided valuable intelligence on the movement of the car carrying the explosives used in the 7 July bombings, and finding the suspected killers of WPC Beshenivsky in November last year.

However, human rights organisation Liberty has raised a number of privacy concerns.

"If this is used to target individuals to try and match a plate to a profile that's fine. But if we're talking about mass surveillance of everyone this could be worrying," said a spokeswoman.

"Bear in mind that the Driver & Vehicle Licensing Agency is still under investigation for selling customer records to private companies."

The new data centre can handle 50 million data requests a day, and has been tested up to 100 million. In contrast the BBC website on 7 July crashed after receiving 26 million hits.

The ANPR system was first trialled in Docklands as part of the Ring of Steel (or ring of plastic as it became known) installed after the Baltic Exchange bombing by the IRA.

Anite Group is now looking to start a system to link the UK's CCTV cameras to provide a similar service for facial recognition.

"Such a system could not be used to track individuals personally, as that's the wrong data set," said Lee Hendricks, managing director for secure information solutions at Anite.

"What it can do is reduce the load on human analysts studying footage of crimes. It could cut the need to view two million faces down to around 150, hugely increasing the speed with which criminals can be identified."

The company is now looking to start a trial of such a system, either within a specific area such as Docklands, or at Paddington Station or the new Wembley Stadium.