The BBC has learned that a national network of cameras watching over Britain's roads will be in place within months.
There are already thousands of Automatic Number Plate Recognition cameras that can read and log registration plates, but soon police forces in England, Wales and Scotland will be able to share the information in one central computer.
Officers say it is a useful crime-fighting tool but critics say the network is secretive and unregulated.
Richard Bilton reports.
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Who's Watching You
The three part series Who's Watching You begins on Monday 25 May, 2009 at 2100 BST on BBC Two.