The strategic message for the market is clear. Capacity is judged to sit disproportionately in outer London, and the boroughs that have historically carried the heaviest numbers (notably Tower Hamlets, Newham and Barking & Dagenham) are being asked to do less than before. For landowners and promoters, the centre of gravity for large-scale opportunity is moving towards the outer ring.
Brownfield first, but not brownfield only
Brownfield land remains the priority, and City Hall expects around 90 per cent of delivery to come from previously developed land. But the Plan accepts that brownfield alone cannot meet London's long-term needs. It therefore introduces a greenfield (read, Green Belt) sub-target of around 56,100 homes over the period, concentrated in eight boroughs: Barking & Dagenham (1,140), Barnet (7,000), Croydon (5,600), Enfield (7,000), Harrow (3,150), Havering (12,060), Hillingdon (14,750) and Redbridge (5,400). Release itself remains a matter for boroughs through their local plans, guided by Policy PV7, which permits limited and selective Green Belt release only in sustainable, well-connected locations that deliver substantial affordable housing (a 50 per cent threshold on Green Belt land), biodiversity net gain and improved public access to green space. The 10 and 20 year key diagrams identify some potential areas of search, but these are currently symbols on a map without defined boundaries.
The scale of the affordable housing ambition sits alongside these numbers. On the GLA's own account, the 558,000 total is intended to include some 220,000 low-cost rented homes and 120,000 intermediate homes over the decade. That ambition would "need to be underpinned" by grant funding well beyond the current record £11.7 billion ten-year allocation, which is expected to fund only around 53,000 homes. The dependence on national funding is therefore not incidental to the Plan; it is central to whether even the reduced target is achievable.
The longer game to 2047, and its dependencies
The Plan seeks to increase its delivery beyond 2037, but it does not seek to make up the shortfall created in the first ten years of the plan. It aims to deliver 850,000 homes between 2037 and 2047, and instructs boroughs to plan proactively for that longer-term capacity. The mechanisms include safeguarding candidate future broad locations for growth, the managed release of industrial and Green Belt land, further phases of Opportunity Areas, and continued reliance on small sites. The Mayor commits to monitor delivery and increase targets as conditions improve.
Critically, much of the post-2037 capacity is contingent on major transport investment that is not yet funded. The Plan links the West London Orbital, a Bakerloo Line extension (ultimately to Hayes) and ‘metroisation’ of South Central rail lines to substantial additional housing capacity, on the order of tens of thousands of homes for each scheme. None of this sits within the Mayor's gift; it depends on decisions in Whitehall. The 20 year key diagram which identifies potential sites, including further Green Belt locations, should therefore be taken with a large pinch of salt. We can also expect further long running discussions over the approach that boroughs Local Plans (which will form a longer 15 year timeline) for the period to 2037 take place at their own Examinations.
What this means for you
For landowners and developers, the redistribution is the story. Outer London boroughs with rising targets and, in eight cases, an explicit Green Belt component are where strategic land and promotion activity is most likely to be rewarded, particularly around stations and well-connected corridors. Investors should weigh the delivery risk carefully: the 558,000 figure is itself conditional on grant, viability recovery and infrastructure, and the longer-term numbers are more conditional still. And all parties should watch the government's response closely, because intervention by the Secretary of State could reshape the numbers before the Plan is adopted. The consultation is open until 15 October 2026, and there is a clear commercial case for engaging with it where borough-level targets or Green Belt designations affect specific landholdings.
