Policy and legislative context 

Policy HO4: Land for strategic site development of the National Planning Policy Framework 2026 sets out the need for local and strategic plans to identify suitable locations for large scale development that can be supported by infrastructure and facilities, will be sustainable, address environmental opportunities and constraints set out in Local Nature Recovery Strategies. Policy HO4 (2) provides a high level framework for setting expectations for the quality of places, making an assessment of build out rates, and requiring a mix of tenures to meet the needs of different groups. As under the previous NPPF, it also includes the TCPA’s Garden City Principles as an example of placemaking principles that may be relevant to strategic sites.

Policy HO13: Build out of residential and strategic sites, relates to development management for these strategic sites, stating the need for developments to have a reasonable prospect of delivery at application stage. It urges Local Planning Authorities to consider the timing of development and whether this could be controlled through planning conditions where appropriate. Policy HO13 (3) also introduces a new set of considerations intended to create flexibility for large-multiphased outline planning permissions. It states that the consenting framework for a strategic site, should “Set out the parameters and requirements for the design, infrastructure and other features of the development (including the quantity and type of affordable housing to be provided)”. However, it requires this to be tailored to the scale of development, i.e. proportionate, and also urges the need to “be flexible enough to respond positively to changing circumstances as phases are brought forward, including changes to housing need, infrastructure requirements, viability and design”.

The Government stated in the December 2025 consultation document that Policy HO13 “reflects concerns that the current system demands excessive detail and certainty for large scale, multi-phase schemes up-front, which can make the delivery of these schemes challenging.” In its August 2026 consultation response, Government stated that its aim is to “clarify the balance between securing key requirements up-front and allowing appropriate flexibility as phases come forward. The policy makes clear that consenting frameworks should establish parameters for matters including design, infrastructure and affordable housing, while ensuring that the level of detail is proportionate to the scale and phasing of development.” The policy also includes a new requirement to ensure that development proposals which would be inconsistent with emerging plans for large scale development can be resisted, to better safeguard these development opportunities, in line with Policy DM4 (2) on prematurity, which sets out clear criteria for prematurity for sites at the strategic scale.

The current government’s draft New Towns programme is limited to supporting a small number of places to deliver growth at a scale over and above 10,000 homes. Whilst not reflective of government policy, the New Towns taskforce identified that “This is more than the private sector is currently bringing to the market independently and will facilitate a new system-wide approach to building large settlements”. Even so, government stated in its initial response that “We are determined to get spades in the ground on at least three new towns in this Parliament and the government is prepared to progress work on a far larger range of locations if it proves possible.”

And further to this, that “”Our ambition is that new towns will act as exemplars for integrated planning and funding, setting a model for future large-scale development that will change the way that housing is delivered in this country, beyond the programme itself.” The New Towns Taskforce have stated that of the 100+ sites submitted to the New Towns Programme for consideration, many represented highly credible large-scale developments, many of which may come forward in spite of not being selected for this programme, including via future government support. The Draft New Towns programme confirms that there remains “strong potential to deliver housing in places that are not taken forward as new towns”, particularly the six shortlisted reasonable alternative sites.  

Spatial Development Strategies (SDSs) are new subregional development frameworks which Strategic Authorities are required to prepare for their areas as set out in the Planning and Infrastructure Act 2025. Government continues to clarify the legislative and policy framework for subregional spatial development strategies against the backdrop of ongoing local government reorganisation but aims to have these produced by 2029. However, SDSs cannot themselves allocate sites for development – only outline the opportunities and designate broad areas of search that could be considered for new communities. While they can begin to establish some of the evidence base around housing need, they will not be able to provide the detailed viability or deliverability evidence, or to consider the environmental or other impacts of schemes in the way that local plans can.

NPPF Policy PM1: Spatial Development Strategies states that SDSs should identify “broad locations for growth and regeneration, including new settlements, major urban extensions, major cross boundary development and other key locations with the potential for significant new homes”. It also makes clear that broad locations should extend over any strategic sites already in adopted Local Plans, meaning that SDSs must at least consider the potential for further growth at major development sites, particularly over the mandatory 25 year plan period they must cover. The glossary defines such sites as typically being those above 1,500 homes across multiple phases.

NPPF Policy PM2: Local Plans however, states that local plans only required to cover a 10 year plan making period as a minimum, far shorter than most strategic site trajectories, and previous references to a 30 year plan period where strategic sites are involved have been removed. This appears to emphasize the role of SDSs in identifying appropriate locations for strategic sites, whilst still enabling Local Plans to identify these in their own right. Further guidance will also be published to further support authorities operating across the two tiers, including on the relationship between broad locations identified in SDSs and subsequent site allocations in local plans. However, there appears to be some tension between the longer time horizons required of SDSs and their strategic nature, which will span beyond typical viability considerations, and the shorter minimum time horizons now required of local plans.

Government has also stated its ambition to further devolve powers around housing, planning, transport and funding in all areas, including some currently held by Homes England, to align with those held by the Mayor of London. Mayoral authorities, once fully established, will have the power to designate Mayoral Development Corporations which could then prepare a local plan specific to a site, thereby designating it for development, or take forward existing consents for delivery as has been done at Ebbsfleet. See Case Study 1 for more details. 

New Town Development Corporations, Mayoral Development Corporations and Urban Development Corporations were historically different models created with different powers and for different purposes. Recent changes to legislation under the Levelling up and Regeneration Act and Planning and Infrastructure Act however have created a more level playing field between the five types of development corporations that can be established by the Secretary of State and Mayors, although Levelling up and Regeneration Act Section 172 which enables locally initiated and led development corporations has yet to commence. All development corporations must now also have regard to sustainable development and climate change mitigation and adaptation. The government has stated that its objective in amending legislation was to create a clearer, more flexible and robust framework for the operation of Development Corporations, reflecting the emerging thinking of the New Towns Taskforce. 

For further detail about the different types of development corporations, including a downloadable resource comparing different types, see the Development Corporations page in this guide. 

In some circumstances, compulsory purchase can be a key delivery tool to unlock large housing schemes with public sector intervention to support land assembly.  Land assembly involves a delivery vehicle or master developer taking on the risk of combining multiple land holdings into a single plot to enable a road, health centre, school or other vital part of a scheme to be delivered. This is particularly the case where land ownership is fragmented or in existing use, has ransom strips or other title defects, and where lengthy negotiations on acquisition prevent the timely and coordinated delivery of transport or social infrastructure, for example. Local delivery vehicles may utilise compulsory purchase in different ways, but can often negotiate with landowners without resorting to formal measures, with the powers acting only as a backstop for these negotiations. 

The Planning and Infrastructure Act 2025 builds on reforms introduced through the Levelling Up and Regeneration Act 2023, which amended compulsory purchase powers for both development corporations and local authorities. These changes allow acquiring authorities, in certain circumstances, to disregard ‘hope value’ associated with potential future development where land is being acquired for public infrastructure and facilities such as healthcare, education and affordable housing. Under the amended regime, certain prescribed bodies may apply for a section 14A direction to do so under the Land Compensation Act when submitting a compulsory purchase order (CPO) for confirmation.

Responsibility for granting these directions now falls within the remit of Planning Inspectors, which should, in principle, make the process more accessible to authorities. A robust funding, viability and planning case will still be required to demonstrate scheme delivery and the public interest case. New conditional CPOs could also further streamline the process, allowing CPOs to be approved in principle subject to specific requirements, such as securing final funding or obtaining planning permissions. These orders remain inactive until conditions are officially met and discharged, and could help to hold land at or closer to existing use value while schemes are progressed than is currently the case. 

Although these revised approaches have yet to be tested through the courts, the clear policy intention is to streamline CPO processes where delivery is in the public interest and where landowners are not collaborating. Government has stated its aim to ‘improve the CPO process and land compensation rules to enable more effective land assembly through public sector-led schemes’ to “speed-up and lower the costs of the delivery of housing, infrastructure, amenity and transport benefits in the public interest.” By reducing the value attributed to land required for public infrastructure on major sites, the reforms aim to support more sustainable and effective placemaking outcomes and speed up the delivery of schemes – if even to suppress land values through the threat of compulsory purchase more than its actual use.