4.—(1) If in relation to any area the Department or, in relation to the district of a council, that council is satisfied that it is expedient that development described in any Part, Class or paragraph in the Schedule, other than development within Part 16 should not be carried out unless permission is granted for it on an application, the Department or that council may, subject to paragraph (2) give a direction that the permission granted by Article 3 shall not apply to—
(a)all or any development of the Part, Class or paragraph in question in any particular area specified in the direction; or
(b)any particular development, falling within that Part, Class or paragraph, which is specified in the direction.
(2) Subject to paragraph (4), a direction by a council under this Article shall require the approval of the Department who may approve the direction with or without modifications.
(3) When a council submits a direction to the Department for approval, it shall also send—
(a)two additional copies together with a plan of the area in respect of which the direction applies, unless the direction includes such a plan; and
(b)a statement of its reasons for making the direction.
(4) The approval of the Department is not required in the case of a direction which does not affect the carrying out of such development by a statutory undertaker as is referred to in paragraph 6 and which relates only to either or both of the following—
(a)a listed building;
(b)development within the curtilage of a listed building.
(5) A direction under paragraph (1) shall not affect the carrying out of—
(a)development permitted by Part 12;
(b)development permitted by Class B of Part 23;
(c)development permitted by Part 31 and Part 32;
(d)any development in an emergency other than development permitted by Part 31; or
(e)any development mentioned in Part 18, unless the direction specifically so provides.
(6) A direction given or having effect as if given under this Article shall not, unless the direction so provides, affect the carrying out by statutory or other undertakers of the following descriptions of development—
(a)the maintenance of bridges, buildings and railway stations;
(b)the alteration and maintenance of railway track, and the provision and maintenance of track equipment, including signal boxes, signalling apparatus and other appliances and works required in connection with the movement of traffic by rail;
(c)the maintenance of docks, harbours, quays and wharves;
(d)the provision and maintenance of mechanical apparatus or appliances (including signalling equipment) required for the purposes of shipping or in connection with the embarking, disembarking, loading, discharging or transport of passengers, livestock or goods at a dock, quay, harbour, bank wharf or basin;
(e)any development required in connection with the improvement, maintenance or repair of watercourses or drainage works;
(f)the maintenance of buildings, runways, taxiways or aprons at an airport;
(g)the provision, alteration and maintenance of equipment, apparatus and works at an airport, required in connection with the movement of traffic by air (other than buildings, the construction, erection, reconstruction or alteration of which is permitted by Class A of Part 15).