Budget 2026 will hold back major changes to Building Regulations for the remainder of this Parliament and exempt residential brownfield developments of up to 1.5 hectares in England from Biodiversity Net Gain requirements.
The Budget published by HM Treasury also requires local planning authorities to digitise and publish key planning documents as open data by the end of 2027. MHCLG's PlanAssist planning tool is due to be made available to all councils in England by the same deadline, subject to further testing.
The measures form part of the wider construction and housing package examined in LCM's construction analysis of Budget 2026, which also covers the £1.5bn Social and Affordable Homes Programme uplift, infrastructure investment, data centres, skills and the OBR's reduced housing-supply forecast.
Construction and regeneration at Greenwich Peninsula, London. Budget 2026 includes changes to Biodiversity Net Gain requirements for qualifying residential brownfield sites in England. Photo: London Construction Magazine.
Major Building Regulations changes put on hold
The Government says it will make no major changes to Building Regulations for the remainder of this Parliament. Building-safety reforms are excluded from that commitment, including work required to implement recommendations from the Grenfell Tower Inquiry.
Smaller amendments are still possible. The Budget says the Government will continue considering changes where existing requirements could be made more proportionate to support development, so the commitment is a pause in major reform rather than a complete freeze on every regulatory amendment.
For higher-risk buildings, the existing Building Safety Regulator approval regime continues. Gateway 2 remains the building-control approval stage that must be cleared before regulated higher-risk building work can begin; the Budget does not remove that statutory hard stop.
LCM's Gateway 2 Approval Index separately tracks approval rates, live applications, determination periods and project starts across the higher-risk building regime.
Brownfield housing sites gain BNG exemption
Residential brownfield developments on sites of up to 1.5 hectares in England are to be exempted from Biodiversity Net Gain requirements. The Government says the change is intended to reduce development costs and support its brownfield-first housing policy.
The implementation date has not yet been set. The Government will publish its full response to the consultation and an impact assessment before confirming when the exemption takes effect.
The change is confined to qualifying residential brownfield sites. Biodiversity Net Gain is moving in the opposite direction for some major infrastructure: it becomes mandatory for Nationally Significant Infrastructure Projects from November 2026.
That produces two different regulatory tracks from the same Budget. Smaller qualifying brownfield housing schemes will lose the BNG requirement once the exemption is implemented, while nationally significant infrastructure projects will enter mandatory BNG from November.
Planning documents must become open data
The Budget also sets an end-2027 deadline for local planning authorities in England to digitise and publish key planning documents as open data. The requirement is intended to support wider adoption of digital and AI-assisted planning systems.
For developers and consultants, greater standardisation could change how planning records are searched and monitored across different authorities. Planning applications, supporting documents and decisions are currently presented through a wide range of council systems and document formats; a more structured open-data layer would make automated project tracking easier if the final technical standard is applied consistently.
MHCLG also intends to make PlanAssist available to every English council by the end of 2027, subject to further testing. The Budget describes the tool as part of the Government's programme to increase the use of AI in planning administration.
Housing delivery remains the test
The regulatory changes arrive alongside a £1.5bn increase in Social and Affordable Homes Programme funding and the new £4.7bn Your First Home scheme. The OBR has nevertheless reduced its cumulative forecast for net additions to the housing stock by 190,000 homes compared with its March forecast.
Its assessment identifies regulation alongside borrowing costs, construction costs and weak demand as factors affecting housing delivery. The Budget's response now combines additional housing funding with fewer major Building Regulations changes, the proposed brownfield BNG exemption and a push to digitise planning records.
The next formal step for the brownfield measure is publication of the Government's consultation response and impact assessment, which will set the implementation timetable for the 1.5-hectare exemption.
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