Government confirms major updates to Biodiversity Net Gain (BNG) framework

The Government has published a significant package of updates to the operation of Biodiversity Net Gain (BNG), building on the first two years of its implementation across the planning system.

 

Since becoming mandatory, BNG has begun to reshape how development and nature are considered together, with early evidence suggesting it could prevent the loss of between 6,000 and 10,000 hectares of habitat each year, while also encouraging earlier, more nature‑led design decisions. The Government has emphasised that these changes help provide certainty, reduce late‑stage redesign and support the delivery of housing and infrastructure.

 

The latest announcements are intended to strengthen and streamline BNG, responding directly to feedback from local authorities, developers, ecologists and infrastructure providers.

BNG to apply to Nationally Significant Infrastructure Projects from November 2026

 

One of the most notable changes is confirmation that BNG will apply to Nationally Significant Infrastructure Projects (NSIPs) – including major transport, energy and water schemes – from November 2026.

 

The introduction date has been adjusted to give promoters sufficient time to incorporate BNG into scheme design and delivery, supporting a smooth transition from voluntary to mandatory provision. The Government has confirmed that supporting secondary legislation and final gain statements will be brought forward shortly to provide clarity and certainty.

 

Importantly, a streamlined BNG framework will apply to NSIPs. This will:

 

• focus only on habitats affected by development (rather than entire sites);
• simplify requirements where habitat impacts are temporary; and
• allow retained, enhanced or newly created on‑site habitats to count towards BNG.

 

Once mandatory, NSIP promoters will also be able to use the full range of delivery options, including registered off‑site biodiversity gains and statutory credits where appropriate. Further guidance is expected to clarify how BNG should be applied in the NSIP context.

 

Targeted changes to support SME and minor development

 

The Government has also confirmed a suite of targeted changes aimed at improving proportionality and flexibility for smaller developments, recognising the role SME developers play in housing delivery and local growth.

 

Subject to parliamentary scheduling, by July 2026 the Government expects to:

 

• introduce a new 0.2 hectare area‑based exemption;
• remove the existing self‑ and custom‑build exemption;
• exempt temporary planning permissions of up to five years; and
• amend the biodiversity gain hierarchy for minor development so that off‑site gains are treated on an equal footing with on‑site provision.

 

Later in 2026, further exemptions are expected for:

 

• development whose primary purpose is to conserve or enhance biodiversity; and
• schemes that enhance parks, playing fields and public gardens.

 

Updates to the statutory biodiversity metric

 

Changes are also planned to the statutory biodiversity metric, including:

 

• revised assessment of spatial risk using Local Nature Recovery Strategy areas only;
• improved identification and assessment of urban habitats, including Open Mosaic Habitat;
• introduction of proxy habitats where OMH units are unavailable;
• potential changes to watercourse assessment; and
• a move from Excel‑based tools to a fully digital, integrated metric service, improving accessibility for small developers.

 

The Government anticipates that the use of the de minimis exemption will reduce significantly once the new area‑based exemption is in place.

 

Guidance, transitional arrangements and next steps

 

Updated guidance, planning application forms and gain plan templates will be issued to reflect legislative changes. Transitional arrangements will also be set out to explain how applications submitted during phased implementation should be handled.

 

Until the changes take effect, the current BNG requirements remain fully in force, and developers should continue to follow existing legislation and planning practice guidance.

 

Consultation on residential brownfield development

 

Alongside these announcements, the Government has launched a new consultation exploring a targeted BNG exemption for residential brownfield development, supporting a “brownfield first” approach to housing delivery.

 

The consultation seeks views on:

 

• how residential brownfield development should be defined;
• possible size thresholds; and
• how any exemption could avoid negative environmental impacts.

The consultation closes at 23:59 on 10 June 2026.

 

What this means for planning and development

 

Collectively, these updates represent a maturing of the BNG framework, balancing ambitious biodiversity outcomes with greater clarity and proportionality across different types of development. While the changes are significant, the Government has emphasised that once embedded they should provide greater certainty, supporting delivery while keeping nature at the heart of placemaking.

 

At DHA Planning, we continue to advise clients on navigating BNG requirements across planning applications, Local Plan promotion and major infrastructure schemes. If you would like to discuss how these changes may affect your projects, please do get in touch with our team.