The Secretary of State may designate as a class buildings each of which consists of or includes one or more dwellings if it appears to him that—
A dwelling which is, or is included in, a building in a class so designated is referred to in this Part as a "defective dwelling"; and in this Part, in relation to such a dwelling—
A designation shall describe the qualifying defect and specify—
A designation may make different provision in relation to England and Wales; subject to that, a designated class shall not be described by reference to the area in which the buildings concerned are situated.
Notice of a designation shall be published in the London Gazette.
Any question arising as to whether a building is or was at any time in a class designated under this section shall be determined by the Secretary of State.