Planning Reform 2026: What It Means for Development

26 April 2026 · 5 min read · Planning & Development

The revised National Planning Policy Framework (NPPF), published in December 2024, is now biting. With 157 councils unable to demonstrate a five-year housing land supply and new penalties taking effect from July 2026, the planning landscape has shifted decisively in favour of development — particularly on marginal and previously undevelopable sites.

The Key Changes

Four reforms are reshaping planning decisions right now:

• Strengthened presumption in favour of sustainable development — the NPPF's "default yes" to development has been reinforced, with fewer matters able to override it. Councils without an up-to-date local plan are particularly exposed.
• Grey Belt development — previously undevelopable Green Belt land that fails to serve Green Belt purposes (poor-quality land, previously developed sites) can now be released for housing, subject to the "Golden Rules": 50% affordable housing, infrastructure improvements, and green space enhancements.
• Six-year housing land supply — from July 2026, councils operating under outdated local plans must demonstrate a six-year supply of deliverable housing sites rather than five. This significantly increases the pressure to approve applications.
• 20% decision-taking buffer — councils whose adopted housing requirement is at 80% or less of the standard method figure face an additional 20% buffer from 1 July 2026. This makes it substantially harder to refuse planning on land supply grounds.

The cumulative effect is clear: where councils can't demonstrate adequate housing land supply, the tilted balance in favour of approval is now heavier. For developers with sites in or adjacent to the Green Belt, the Grey Belt provisions open doors that were firmly shut 18 months ago.

What This Means for Land Values

Land that suddenly becomes developable sees an immediate value shift. Green Belt edge sites and previously developed land within the Grey Belt category are the most obvious winners. But the ripple effect extends further — councils under pressure to approve schemes are more receptive to conventional sites too, reducing planning risk across the board.

For viability appraisals, the key question is how much of the planning uplift is captured by Section 106 obligations, the Golden Rules' 50% affordable housing requirement, and the Community Infrastructure Levy. The answer varies significantly by authority and site classification.

The Golden Rules in Practice

Grey Belt development isn't a free-for-all. The Golden Rules impose substantive obligations that directly affect scheme viability:

• 50% affordable housing — significantly above typical local plan requirements (usually 25–40%). This is the biggest viability constraint on Grey Belt schemes.
• Infrastructure delivery — necessary physical and social infrastructure must be funded as part of the scheme. Schools, transport, and healthcare contributions can be substantial on larger sites.
• Green space improvements — a portion of the site (or contributions) must deliver measurable improvements to the remaining Green Belt.

The 50% affordable housing requirement is the critical viability test. On high-value land (London, South East), Grey Belt schemes may still stack up. On moderate-value sites, the affordable housing percentage may need viability negotiation — but the NPPF's strengthened presumption makes authorities less inclined to accept reduced affordable housing provision.

Impact on Construction Demand

The planning reforms feed directly into the construction cost picture. More sites gaining consent means more schemes entering the construction pipeline — and more demand for the same constrained labour and materials supply discussed in our cost inflation analysis.

The sectors most likely to see increased activity:

• Volume residential — the primary beneficiary. Volume housebuilders are already securing Grey Belt sites in the South East and North West.
• Affordable housing — housing associations and build-to-rent operators are natural partners for the 50% affordable requirement on Grey Belt schemes.
• Infrastructure — the sites need connecting. Road, drainage, and utilities work follows residential land release, typically within 12–24 months of consent.

Practical Steps Now

1. Audit your land portfolio — identify sites in or adjacent to the Green Belt that may now qualify for Grey Belt assessment. The criteria are specific: previously developed land, or land that makes a limited contribution to Green Belt purposes (openness, preventing sprawl, checking unrestricted expansion).
2. Stress-test viability with 50% affordable — don't assume standard affordable housing percentages. Run development appraisals at 50% affordable to identify which sites work and which need a different strategy (phased development, land partnership models).
3. Factor in the July 2026 cliff edge — councils facing the 20% buffer and six-year supply requirement from July will be under intense pressure to approve schemes. Applications submitted before this date benefit from a more favourable policy environment; those after may face capacity constraints in overwhelmed planning departments.
4. Engage early on infrastructure — the Golden Rules require infrastructure delivery, not just contributions. Pre-application discussions should include infrastructure scoping to avoid costly surprises at the planning obligation stage.
5. Review Section 106 templates — the strengthened presumption in favour of development narrows the scope for authorities to refuse on viability grounds. Ensure your viability assessments are robust, but also recognise that the negotiating dynamics have shifted.

Sources: NPPF (revised December 2024); MHCLG planning reform announcements (2025–2026); LexisNexis Green Belt and Grey Belt guidance (2026); Commons Library research briefing SN/SC/934 (2026); Urbanist Architecture 5YHLS analysis (June 2026); NorthEight market analysis. This article is for general guidance only and does not constitute planning or legal advice.