4. The area of water below high water springs enclosed by a line starting from a point on the west shore of the Mull of Kintyre at 55°45'N 5°35'W; then west to a point on the east coast of Islay at 55°45'N 6°03'W; then south, west and north along the shore of Islay to a point on the west coast of Islay at 55°40.1'N 6°30'W; then south to 55°30'N 6°30'W; then east to a point on the west shore of the Mull of Kintyre at 55°30'N 5°40.3'W; then north along the shore to the start point.