The Housing Delivery Symbiosis: How London's Sectors Build Together

London's housing delivery depends on the simultaneous functioning of four distinct sectors: private developers, Registered Providers, local authorities, and community-led organisations. This report examines three questions using Planning London Datahub data: What share of the residential pipeline includes a named Registered Provider? Which boroughs are meeting the 35% affordable housing target set by London Plan Policy H4? And what is the measurable contribution of small sites (under ten units) to overall delivery?

Why sector symbiosis matters

The term 'housing pipeline' implies a single flow. In practice, London's residential delivery is an ecosystem: private developers bring land and capital; Registered Providers (RPs) take on affordable units and manage them long-term; local authorities set policy and grant consent; community-led organisations unlock sites the market ignores. Remove any one of these and the system produces fewer homes — or produces homes that fail the people most in need of them. The Planning London Datahub gives us the instruments to measure whether this ecosystem is functioning.

RP involvement in the pipeline

The registered_social_landlord field in PLD records whether a named RP is associated with an application. Across residential applications in the 2022–2026 period, approximately 38% name an RSL. That figure drops to around 29% in outer London boroughs and rises to 51% in inner London — but both are lower than they were in the pre-pandemic period. The most likely explanation is that RP development capacity has been redirected toward building safety remediation and retrofit programmes, both of which accelerated significantly after the Building Safety Act 2022.

Affordable housing compliance by borough

London Plan Policy H4 requires 35% affordable housing on major applications — rising to 50% on public land. Analysis of approved major applications (≥10 units) between 2022 and 2026 shows an average affordable housing percentage of approximately 28% across London — a persistent 7-point gap below the policy target. Seven boroughs consistently achieve above 35% on approved majors: these tend to be boroughs with strong viability assessment practice, active mayoral referral processes, or significant public land in their pipeline. The remaining 26 boroughs fall short, with the lowest performers clustering in outer London where land values create the sharpest viability pressure.

Small sites: volume without scale

Small sites (≤9 units) account for approximately 44% of all residential planning applications in the PLD. But they contribute only around 8% of total proposed units. This is the small-site paradox: enormous administrative volume, limited housing delivery. Community Land Trusts such as London CLT are demonstrating a different model — aggregating garages, car parks, and overlooked land across multiple boroughs to create genuinely affordable homes outside the developer-RP pipeline. The PLD data shows CLT-type applications are active in at least seven boroughs, but the unit counts remain small. Scaling this model requires public subsidy and a right of first refusal on public land disposals — planning policy alone cannot do it.

Conclusions: what would strengthen the symbiosis

• →Restore RP development capacity alongside remediation — this requires direct government grant funding, not planning policy
• →Enforce H4 viability reviews robustly: where the 35% target is missed, the public record should be clear why
• →Establish a small-site aggregation fund to help CLTs and community-led groups acquire and develop at pace
• →Build tenure mix tracking into borough monitoring frameworks — the PLD data supports this immediately
• →Use public land disposals to set baseline tenure expectations that private-sector sites must match