At the end of section 3 (supplementary provisions in relation to the power to develop land) there shall be added the following subsection—

“(4)

For the purposes of this section (except in so far as it relates to powers conferred by section 2(1)(b) of this Act) and of section 2(1)(a) and (c) and (2) of this Act " local authority " means a district council, an islands council, a general planning authority or a district planning authority ; and for the purposes of section 2(1)(b) of this Act means a regional, islands or district council or a planning authority.”.