Alarm over shopping radio tags

Supermarkets have already brought everything under the sun under one roof, and along the way been accused of denuding the High Street of butcher, baker and candlestick-maker.

Now they are introducing a new technology that some say threatens a fundamental invasion of our privacy.

We are all familiar with barcodes, those product fingerprints that save cashiers the bother of keying in the code number of everything we buy. Now, meet their replacement: the RFID tag, or radio frequency ID tag.