So far, it is chuffed with the results, which have seen payphone attacks fall by two- thirds. Thirty attacks have been detected and five robbers arrested before they could leg it with their swag.
BT now plans a further trial with 500 call boxes. The alarms are the most recent in a steady stream of anti-theft measures BT has dabbled with. These have included warble alarms, flashing lights (not blue ones) and a loudspeaker that berates the robber for setting about the money box. BT did not react well to Bunhill's sugestion that it should attach all four measures to one call box and video the reaction of the unlucky villain. 'We are not Jeremy Beadle,' sniffed a spokesperson.