As combined mayoral authorities start to take shape across the South East over the next 1-2 years, the future of housing and planning looks set for a major reset.
The new Planning and Infrastructure Bill (2025) requires Mayoral Strategic Authorities to develop Spatial Development Strategies - ambitious, long-term blueprints for the built environment and meeting the needs of populations and growth plans. These will carry serious weight in decision-making and, in many areas, may supersede fragmented local plans.
For planners, developers and housing providers, this means fewer layers of sign-off, but also a new set of strategic levers in the hands of regional mayors.
Key tools on the table include:
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Mayoral Community Infrastructure Levy (CIL)
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Strategic referral powers for large or regionally significant developments
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Direction over affordable housing programmes
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Devolved Homes England funding
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Authority to issue Development Orders
Importantly, planning strategies will have to reflect broader economic, transport and environmental goals - pushing housing delivery firmly into a cross-sector, region-first model.
Sussex: boundary shifts and unmet need
In Sussex, where a mayor will be elected in 2026, local authorities have struggled to meet housing targets — particularly in constrained geographies such as Brighton & Hove. Local Government Reorganisation is running in parallel with devolution and will impact any future mayor's planning, with detailed options on new unitary councils due to be submitted by the end of this month.
One proposal from Brighton & Hove City Council is to extend the city boundary eastwards to include Peacehaven, Telscombe and Newhaven. The motivation is in no small part to do with unlocking land and flexibility to meet housing needs that the current footprint can’t accommodate.
If approved, these changes could:
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Widen the planning base to support Brighton’s unmet housing need
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Align housing growth with city-led transport and employment strategies
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Increase access to national investment through a unified mayoral plan
Critics argue this risks undermining local identities and democratic oversight around issues like planning, particularly in more rural or semi-urban areas being absorbed.
Surrey: too many cooks, not enough plans?
Surrey's track record on housing delivery is patchy, with many districts lacking up-to-date local plans. The move to fewer, larger authorities could help - but only if agreement is reached on the structure.
Two main models are proposed:
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Two unitaries: East and West Surrey
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Three unitaries: East, North and West — though this risks falling below the government’s population benchmarks
In a recent blog, the estate agent Savills notes that whichever model is chosen, the reduction in planning authorities could speed up site allocation, remove policy contradictions, and create a more coherent vision for growth.
Surrey’s mayor - expected to be elected in 2027 - will have a big job aligning green belt protections with housing need across one of the most expensive counties in the UK.
Kent: playing catch-up, but with ambition
Kent is further behind. While not part of the government’s fast-track programme, it is working on plans to form three large unitary authorities. This would radically simplify the current two-tier system - but also require agreement between Kent County Council, Medway and 12 district/borough councils.
Housing delivery in Kent is uneven. Growth corridors like Ebbsfleet and Ashford have national significance, while coastal towns continue to struggle. A future combined authority could provide the scale needed to plan infrastructure-led housing delivery - but timelines suggest real progress won’t start until at least 2028.
The bottom line
The plan is that the South East’s future housing strategy will no longer be a district-by-district puzzle.
Instead, a small number of strategic authorities - armed with planning powers and budgets - will set the tone for how, where and what gets built.
But does the speed come at a cost? What do you think?
Whether this leads to greater ambition or a new set of political and financial bottlenecks remains to be seen. But the opportunity is becoming clearer: align housing with transport, skills and sustainability, and the South East could finally move beyond crisis management and into something more strategic.
📎 Full Savills article
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