A radio frequency identification (RFID) system and more particularly a tag comprising a transponder forming parts of such a system. The tag preferably includes a substrate; a transponder mounted on the substrate; the transponder comprising electronic circuitry and an antenna connected to the circuitry; a sense element on the substrate which is sensitive to damage to the substrate and which is connected to a sense input of the circuitry; the antenna comprising a metal layer and the sense element a layer of conductive ink.