Commentary on Sections Development Section 133 – Meaning of “development”
355.Section 133 sets out the meaning of “development” for the purposes of the Act. Everything that is “development” for the purposes of the Town and Country Planning Act 1990 (“the TCPA”) is development for the purposes of the Act, subject to subsections (2) to (4).
356.Section 55(1) of the TCPA defines “development” as “the carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land”, subject to further clarifications in that section.
357.Subsection (2) of section 133 provides that “material change in the use” (which is a term used in the definition of “development” in section 55(1) of the TCPA) includes:
	the conversion in fuel of a generating station to it being fuelled by crude liquid petroleum, a petroleum product or natural gas;
	an increase in the permitted use of an airport (whether permitted by planning permission under the TCPA or an infrastructure consent order made under the Act).
358.Subsection (3) provides that specific works are to be treated as development to the extent that they would not otherwise be development under the TCPA.
359.Development under the TCPA relates to development of land within the areas of planning authorities and not development in the sea outside the boundaries of their areas. Subsection (4) provides that development under the Act includes operations and changes of use in the sea and other areas covered with waters. The extent to which development in the sea is covered in relation to a Significant Infrastructure Project depends on whether the definition of the Significant Infrastructure Project covers development in the “Welsh marine area”. The “Welsh marine area” is defined in section 143.