Having granted The Mail on Sunday a sneak preview of its electronic tagging system for monitoring criminals doing their time at home, GEC’s Marconi Electronic Devices Ltd has been deluged by follow-up calls from journalists of all denominations, and has imposed a news embargo while two official releases are rushed through: at the moment little more is known than that the electronic tags come in two varieties – an ankle device which emits radio signals picked up within a certain radius by a receiver, or a wrist tag which is slotted into a receiver attached to a telephone, to answer random check up calls generated by a central computer.
