Spatial Development Strategies: the new strategic layer of planning in England
Spatial Development Strategies (SDSs) are coming as a core part of the planning framework.
These strategies will shape how cities, regions and sub-regions grow over the next generation. They will influence housing, infrastructure, energy systems, transport investment and environmental protection at a scale far beyond individual local authorities.
For planners, infrastructure providers, and city leaders, SDSs represent both a challenge and an opportunity: a chance to coordinate long-term spatial decisions to create the foundations for sustainable growth but hinging on data and coordination challenges that go far beyond the scale of current plan-making.
What are Spatial Development Strategies?
A Spatial Development Strategy is a high-level spatial plan covering a large area — typically a city region or group of authorities — and looking at least 20 years ahead.
SDSs will:
- Set the long-term spatial framework for growth
- Coordinate housing distribution across local authorities
- Identify strategic infrastructure needs
- Support economic development
- Set out the spatial strategy to improve and enhance the environment and climate resilience
Importantly, SDSs do not allocate individual sites for development. That role remains with local plans. Instead, they establish the strategic context within which those local plans must operate.
Once adopted, an SDS becomes part of the statutory development plan, meaning local plans must be in general conformity with it.
In essence, SDSs answer the big spatial questions:
- Where should growth happen across a region?
- What infrastructure is required to support it?
- How can development contribute to net zero, nature recovery and economic growth?
When are SDSs coming?
The return of strategic planning has been enabled through the Planning and Infrastructure Act, which places a duty on strategic authorities to prepare an SDS. The Government has set out a clear ambition for universal coverage of SDSs by the end of 2029 which means work on preparing SDSs will need start as soon as possible.
Key milestones currently expected include:
2026
- Secondary legislation expected to commence SDS duties
- Strategic Planning Boards created where multiple authorities need to collaborate
2026–2028
- Evidence gathering and early strategy preparation
By 2029
- Government ambition for national SDS coverage across England.
In many areas, the geography of SDSs will align with combined authorities and devolution deals, reflecting functional economic areas and travel-to-work regions.
For places without mayoral authorities, strategic planning boards may be created to bring councils together to produce a shared strategy.
The return of cross-boundary planning
One of the key motivations for SDSs is to solve a persistent problem in the planning system: planning across administrative boundaries.
Housing markets, labour markets, transport networks and energy systems rarely align neatly with local authority boundaries. SDSs enable planning at the scale at which these systems actually operate. Strategic planning at this level can help align transport and land use planning, coordinate strategic infrastructure investment, more adequately address environmental systems such as river catchments and ecological networks. In practice, this means SDSs will often cover large city regions or multi-authority geographies, reflecting real economic and spatial relationships rather than administrative boundaries.
| The Coordination Challenge: SDSs will need to articulate a shared spatial vision for a region, coordinating and aligning the views across multiple stakeholders. With many SDS regions being newly formed, a shared vision and the mechanisms for collaboration may not yet exist. Coordination will require extensive engagement at multiple levels spanning political leadership and key development stakeholders alongside local communities and businesses. Visioning exercises, scenario modelling and spatial storytelling will be critical tools in developing a shared narrative and SDSs that are both technically robust and publicly supported. While SDSs create new boundaries in some cases, wider collaboration will also be critical to ensure infrastructure plans integrate with the strategic national context. |
Digital by default: the role of data and digital planning
One of the most significant changes in how SDSs are developed will be the embedding of digital approaches throughout the process.
The traditional planning process relies heavily on static reports and PDFs. SDSs create an opportunity to move toward digital planning infrastructure, where evidence, engagement and outputs are dynamic and accessible.
Key digital elements are likely to include:
Digital baselines
SDSs will require a comprehensive digital evidence base combining multiple datasets, including:
- population and housing demand
- land availability
- transport connectivity
- energy infrastructure
- economic activity and performance
- employment, skills and health outcomes
- environmental constraints
- climate risk
- nature networks
A digital baseline allows planners to explore spatial patterns and identify strategic opportunities for growth.
Figure 1: Example from CPCA State of the Region Digital Baseline Dashboard, by City Science / Cadence
Figure 2: Example CPCA State of the Region Digital Baseline Dashboard, by City Science / Cadence
Digital engagement
Engagement will be essential — but the scale of SDS geographies makes traditional consultation methods insufficient.
Digital tools can enable:
- interactive mapping
- scenario visualisation
- public feedback linked to places
- continuous engagement throughout plan preparation
This supports a more transparent and participatory planning process.
Digital plans and outputs
Ultimately, SDSs should not exist solely as documents.
Instead, the strategy can become a digital spatial platform that:
- integrates evidence and policy
- visualises growth scenarios
- connects infrastructure planning
- provides a live reference point for local plans and investment decisions
This digital shift aligns with wider government ambitions to modernise the planning system and unlock better decision-making.
| The Digital Challenge: For many organisations, the digital aspects of SDSs will be daunting. Organisations coming together for the first time may find they have different levels of digital maturity, use different datasets, have different levels of capacity, different processes and different systems. The current state of digital planning may further complicate coordination and collaboration. Procurement and contractual challenges may make it difficult to achieve alignment through their existing systems alone. Alongside fast-changing expectations and best-practice it will be essential for SDS regions to identify digital partners who can help them navigate this complexity to achieve their digital ambitions. |
Key technical pillars of SDSs
To be credible and effective, SDSs will require strong evidence across several core technical areas including:
Transport
Transport will be central to SDS development. Strategic spatial plans will need to be grounded in a robust understanding of existing access to jobs and services, future spatial distribution and travel demand scenarios, the network capacity impacts of growth and potential intervention opportunities including active travel, new mobility technologies, and wider trends such as electrification. Robust long-term transport modelling and forecasting will be critical to support development locations are selected to maximise sustainability, identify growth corridors and no regret options, and prioritise investment.
| The Transport Modelling and Appraisal Challenge: SDS regions will need to collectively review their transport evidence base. In cases where organisations are coming together for the first time, aligning transport models quickly and cost-effectively will be a key challenge as these often have different data vintages and systems that complicate consolidation. More automated approaches, or alternative robust forecasting methods may be needed to deliver the evidence within the required timeframes. |
Carbon and energy
As regions continue to pursue net-zero targets, and the energy system continues to electrify, SDSs will increasingly need to align spatial growth with energy infrastructure planning. This will include, close collaboration with RESPs / DNOs with regards to electricity network capacity planning, spatial planning for renewable energy, heat networks and other energy infrastructure, a clear understanding of regional opportunities such as industrial decarbonisation and new energy markets. Linking spatial planning with Local Area Energy Plans and infrastructure delivery pipelines will be key to ensuring that development supports decarbonisation rather than locking in future retrofit costs.
| The Carbon and Energy Challenge: Many combined authorities have already gone through the process of developing Local Area Energy Plans to bring their strategic energy evidence up to a consistent standard. However, where SDS boundaries are changing or new groupings brought together, unification of the energy evidence is unlikely to have taken place. RESPs and Heat Network Zoning are also relatively new considerations, so updates to LAEPs to align to RESP plans and more strongly solidify Heat Network Zones are likely to be recommended in all cases. Broader regional integration will likely be needed, depending on how planning boundaries intersect. Opportunities for other technologies (such as BESS, FLOW, CCS, DACCS, SAF etc.) may also be relevant for particular geographies and may be under-developed within their current plans. For those authorities with LAEPs, stronger pipeline clarity and infrastructure investment certainty will help identify how energy infrastructure bids should be prioritised in the context of other infrastructure decisions. SDSs also present an opportunity to further strengthen and standardise local policies to support sustainable development. |
Nature recovery and climate resilience
SDSs provide an opportunity to plan for nature at a landscape scale, aligning with an integrating Local Nature Recovery Strategies to ensure ecological networks, habitat restoration, green infrastructure and biodiversity are clearly coordinated across boundaries. Given the 20-year time horizon, climate resilience considerations will be essential – strategic development will in fact depend on robust understanding of flood risk, water scarcity and coastal change. Over a 20-year time frame, housing policies and infrastructure planning more broadly may benefit from greater consideration of overheating risks and potential impacts. Understanding how nature recovery and climate resilience can work together to manage water, reduce heating risks and promote natural solutions will be essential for ensuring plans are joined up and not developed in silos.
| The Nature and Climate Resilience Challenge: For many authorities, embedding climate resilience planning may be relatively new with best practice still maturing in the UK. But with the latest data showing the effects of climate change accelerating, it will be essential to consider climatic threats within long-term plans. There are clear areas of overlap between nature and climate resilience, but it will also be essential to robustly consider the spatial trade-offs to ensure nature recovery and resilience are appropriately prioritised within long term plans. Robust frameworks to assess land-use trade-offs will be essential to ensuring nature recovery and climatic resilience measures are not de-prioritised or just included as a bolt-on consideration. |
Where City Science and Cadence can help
Preparing an SDS is a complex, multi-disciplinary exercise that requires new capabilities in digital planning, systems modelling and spatial analysis. City Science and Cadence together provide a powerful combination of capabilities to support this work.
City Science
City Science brings deep expertise in sustainable growth, net zero and robust capacity and infrastructure forecasting necessary to underpin spatial planning. Our key capabilities include: Strategic transport modelling and planning, Energy system planning, including Local Area Energy Plans, heat networks and infrastructure delivery pipelines, Climate resilience analysis, Scenario modelling and spatial analytics, Place-making, visioning and long-term spatial strategy development. Together, these capabilities support evidence-based decision-making and enable regions to test the implications of different growth scenarios across key service and infrastructure provision.
Cadence
Cadence is our award-winning GIS software that helps authorities create Digital Local Plans and SDSs, covering Digital baselines, cross-boundary evidence bases, digital engagement tools and digital outputs to publish the plan. As a cloud-native platform, Cadence can work with any legacy architecture making it easy and cost-effective to implement best-practice digital approaches from the start, and is a proven enabler of cross-authority working with Combined Authorities and Joint Spatial Plans. With over 7,000 pre-curated planning datasets (including industry-leading transport, energy and climate data) alongside specialist templates, Cadence enables you to curate robust, cross-boundary evidence bases quickly, essential for the SDS timelines.
The opportunity ahead
Spatial Development Strategies mark a major shift in the English planning system. Cities and regions will again have the tools to plan growth at the scale it actually happens — aligning housing, infrastructure, energy and nature across whole geographies. If done well, SDSs should create clearer long-term visions for places, unlock coordinated infrastructure investment, accelerate housing delivery, embed net-zero transitions and strengthen nature recovery. But success will depend on new approaches — particularly digital planning, integrated infrastructure modelling and meaningful engagement.
This is where the right combination of data, modelling and spatial thinking can turn a strategy into a powerful framework for shaping the future of places.
Contact Us Today for a Free SDS Consultation:
Our experts would be happy to talk you through our latest thinking on SDSs, our digital tools designed to help simplify them and discuss your ambitions and objectives. If you would like to confidentially discuss your SDS readiness and plans, please reach out today at info@cityscience.com.