BR shall complete its programme of equipping major signal boxes with direct lines to the appropriate electrical control and equipping other signal boxes with priority emergency dialling systems. Those direct lines and emergency dialling systems shall be logged and tested daily. The purpose of this programme shall be to ensure that: (i) the signalman is able to take full responsibility for ensuring that the area surrounding the accident site is electrically isolated; (ii) the action is confirmed to the signalman, the emergency services, and the BR officials at site; and (iii) the boundaries of isolation are similarly confirmed.