What is a Spatial Development Strategy?

In statute

Section 58 of the Planning and Infrastructure Act 2025 inserts new sections 12A to 12W into the Planning and Compulsory Purchase Act 2004.

Inserted section 12A(1) requires strategic planning authorities to prepare a document, conforming to section 12D, known as a spatial development strategy.

Inserted section 12D requires an SDS to include:

• a statement of the authority's policies, however expressed, for the development and use of land in the strategy area that are of strategic importance to that area
• a reasoned justification for those policies
• the period for which the SDS is to have effect

It may specify or describe strategically important infrastructure, and an amount or distribution of housing, including affordable housing. A matter can be of strategic importance even if it affects only part of the area.

It must be designed so that the use and development of land contribute to mitigating and adapting to climate change, and must take account of any relevant local nature recovery strategy under section 104 of the Environment Act 2021.

It must not:

• include anything that is not permitted or required by section 12D
• specify particular sites where development should take place
• be inconsistent with, or in substance repeat, any national development management policy

In national policy

Policy PM1 of the August 2026 NPPF says an SDS should set a positive vision for growth and change at a sub-regional scale. Its content should be genuinely strategic, leaving detail to other parts of the development plan.

PM1 lists nine things an SDS should do. In short: a growth strategy of at least 25 years, including housing apportionment; broad locations for growth and regeneration (including new settlements and major urban extensions); a spatial framework for economic growth; the general extent of Green Belt and where boundary changes may need to be considered in local plans; broad locations for nature and the historic environment; the type, extent and broad location of strategic infrastructure; maps and diagrams; delivery mechanisms; and monitoring, with work on a replacement started no later than seven years after adoption (or earlier in stated cases).

What government has said it is not

The February 2026 MHCLG paper is explicit:

SDSs are not big local plans. They cannot be site-specific or allocate/designate particular sites.

Site allocation stays with local plans. Those local plans will have to be in general conformity with the adopted SDS.

London

London has had an SDS for more than twenty years: the London Plan, prepared under the Greater London Authority Act 1999. That continues. The rest of England uses the 2025 Act once those provisions are commenced.