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Travelling without satellite navigation has become unthinkable for many drivers, including the criminal fraternity, it would seem.
Police are finding them a valuable aid to implicating their owners in crimes, as forensics experts can extract information about a suspect's whereabouts from the devices.
Analysis of the satnavs has helped officers in Britain solve dozens of investigations into kidnappings, grooming of children, murder and terrorism.
Information about a suspect's whereabouts at particular times, their journeys and the addresses of associates can be discovered if they have been using a satnav. The units retain hundreds of records of past locations and routes in their internal memory.
With more than 30 million devices being used in the UK and in modern mobile phones, police expect the data to become an increasingly important forensic tool.