4. The lines dividing landward areas from seaward areas in the vicinity of the Pentland Firth and the Orkney Islands are—
(a)a straight line drawn from the map reference point ND 310753, being a point situated on the low water line on or adjacent to the feature known as St John’s Point, to the map reference point ND 289809;
(b)from the map reference point ND 289809, a line running clockwise parallel with, and three nautical miles seaward of, the baselines from which the breadth of the territorial sea adjacent to the Orkney Islands is measured to the map reference point ND 459711; and
(c)from the map reference point ND 459711, a straight line to the map reference point ND 407734, being a point situated on the low water line on or adjacent to the feature known as Duncansby Head.