71.—(1) A planning authority may acquire, by agreement or compulsorily, any protected structure situated within its functional area if—

(a) it appears to the planning authority that it is necessary to do so for the protection of the structure, and

(b) in the case of a compulsory acquisition, the structure is not lawfully occupied as a dwelling house by any person other than a person employed as a caretaker.

(2) In this section and sections 72 to 77, a reference to a protected structure shall be construed to include a reference to any land which—

(a) forms part of the attendant ground of that structure, and

(b) is, in the planning authority’s opinion, necessary to secure the protection of that structure,

whether or not the land lies within the curtilage of the structure or is specified as a feature in the record of protected structures.