Televisions, DVD players and computers could be fitted with microchips identifying their location and their normal proximity to each other, automatically alerting police if they change unexpectedly, according to a scientist on Wednesday.

"We haven't yet proved the technology will do it, but we are confident it will," Professor Nigel Linge from Britain's Center for Networking Telecommunications Research told reporters.

He said a police-monitored pilot project testing the hybrid wireless and mobile phone technology should be up and running within six months in the northern English city of Manchester.

The technology could probably locate a tagged machine down to the nearest meter, he added.

Speaking at the annual meeting of the British Association for the Advancement of Science, Linge said there were even talks about installing global positioning technology in cars that could regulate speed remotely.

"If you are in a 30 miles an hour zone, the system would automatically prevent the car going over that speed," he said.

Linge said he was well aware of the potential implication for civil liberties of the intrusive potential of the new technology, but at present he was focusing only on the technical aspects.