59.Section 39 imposes a statutory duty on persons and bodies responsible for preparing RSSs and LDDs in England, and the Wales Spatial Plan and local development plans in Wales. It applies therefore to RPBs and local planning authorities in England and local planning authorities in Wales. It also applies where necessary to the Secretary of State in England and the National Assembly for Wales.
60.In exercising those functions, the persons or bodies concerned must do so with the objective of contributing to the achievement of sustainable development. The persons or bodies therefore need to consider how the policies and plans set out in those documents will contribute to this objective. In doing so, they must have regard to policies and guidance on sustainable development issued by the Secretary of State or the National Assembly of Wales.