91(1)Where any works for the erection or alteration of a building had been begun but not completed before the appointed day, then if—
(a)immediately before that day those works could have been completed in conformity with the provisions of a planning scheme or of permission granted thereunder, or in accordance with permission granted by or under an interim development order; and
(b)where any permission was required under the Restriction of Ribbon Development Act 1935 for the carrying out of those works, that permission was granted,
planning permission shall be deemed to have been granted in respect of the completion of those works.
(2)The planning permission deemed to have been granted by virtue of this paragraph shall be deemed to have been so granted subject to any conditions applicable thereto under the scheme or the permission granted by or under the interim development order, as the case may be, and to any conditions imposed by the permission (if any) granted under the Restriction of Ribbon Development Act 1935 and shall include permission to use the building, when erected or altered—
(a)where the purpose for which it could be so used was prescribed by or under the planning scheme, or by the permission granted by or under the interim development order, as the case may be, for that purpose ;
(b)in any other case, for the purpose for which the building, or the building as altered, was designed.
(3)In relation to any such works as are mentioned in sub-paragraph (1) of this paragraph, being works in respect of which permission was granted after 21st July 1943, on an application in that behalf made under an interim development order, the provisions of this paragraph shall have effect in substitution for the provisions of paragraph 90 of this Schedule.