The government has opened a major consultation on the future of the English planning system, one that marks the most significant rewrite of the National Planning Policy Framework (NPPF) since its debut more than a decade ago. While the consultation spans wide-ranging planning reforms, one feature stands out for developers, planning authorities, ecologists, and communities alike: a targeted reshaping of Biodiversity Net Gain (BNG), including a landmark change exempting development sites below 0.2 hectares from BNG requirements.
This seemingly small numerical shift is poised to deliver substantial implications for SME developers, local planning authorities, and the broader trajectory of nature recovery. Below is a comprehensive review of the reforms, the rationale behind the 0.2-hectare change, and how the new rules aim to balance growth and environmental protection more effectively.
A More Rules-Based, Predictable Planning System
At the centre of the reform package is a commitment to rebuild planning into a clearer, more rules-based regime. By giving certainty to developers and councils about what types of development are acceptable and what requirements will apply, the government intends to reduce friction, shorten timelines, and promote confidence in investment.
The ambition is to support growth while ensuring that nature recovery becomes a routine, embedded part of development practice, not an obstacle to it. The overarching message is one of integration: environmental protection and housing delivery should reinforce, not undermine, one another.
BNG: Strong Performance Overall, but Disproportionate Pressure on Small Sites
Since becoming mandatory in 2024, Biodiversity Net Gain has reshaped the way development interacts with nature. Developers are increasingly consulting ecologists earlier in the process, revising layouts to minimise harm, and designing schemes to incorporate more habitat onsite.
Early data suggest that BNG is preventing habitat loss equivalent to 6,000–10,000 hectares per year in England, a land area roughly matching the entire city of Nottingham. This confirms the environmental rationale for BNG: it is a tangible, quantifiable mechanism for protecting and enhancing biodiversity at the national scale.
However, the implementation phase has exposed clear disparities. Large developments have adapted well, absorbing the costs and integrating design changes relatively efficiently. Smaller developments—particularly those on constrained or previously developed (brownfield) plots have faced greater challenges. For SME developers, the cost of surveys, metric calculations, and off-site unit purchases can disproportionately affect viability.
The government has acknowledged this through the consultation response and is now introducing targeted adjustments to remove unnecessary burdens without diluting the core environmental objectives of BNG.
The 0.2 Hectare Exemption: A Strategic Release Valve for SMEs
The most consequential change is the new exemption for developments on sites below 0.2 hectares, removing their obligation to deliver BNG.
This adjustment aims to:
- reduce cost pressures on SME housebuilders
- accelerate small-scale housing delivery
- relieve local planning authorities of thousands of minor BNG reviews
- preserve BNG’s effectiveness on the larger, higher-impact schemes where it delivers the most environmental value
For context, a 0.2-hectare plot is equivalent to 2,000 square metres sufficient for modest infill housing, small clusters of dwellings, or conversions with limited footprint expansion. These are precisely the types of schemes that the government sees as essential to meeting housing needs in rural villages, market towns, and urban infill locations.
The exemption also acts as a simplification mechanism. By removing BNG obligations from the most administratively cumbersome and least ecologically impactful developments, the system becomes more efficient for all stakeholders.
Brownfield Flexibility: A Further Exemption Under Review
The consultation will also explore whether an additional exemption should apply to brownfield residential sites up to 2.5 hectares, subject to safeguarding definitions and evidence. The idea is to strike a pragmatic balance: enable housing delivery on land with low existing ecological value while maintaining BNG’s protective force where it is most needed.
This reflects the government’s recognition that brownfield redevelopment often carries high remediation costs. Removing or simplifying BNG obligations could unlock stalled sites and support sustainable urban regeneration.
Improving Offsite BNG Delivery
The government plans to introduce further measures to make off-site BNG delivery easier, quicker and more cost-effective. These include streamlining registration processes, increasing transparency around unit supply, and potentially introducing additional market mechanisms.
It is hoped that these improvements will benefit all development types, not just those affected by the new exemptions. They also align with the emerging Nature Restoration Fund, which will channel contributions from developers into strategic, landscape-scale ecological projects.
Nature-Friendly Design as the New Norm
Beyond BNG, the consultation outlines a broader shift toward embedding nature into everyday development through simple, high-impact design measures. These include:
- mandatory nature-friendly building features such as swift bricks
- hedgehog highways and similar urban wildlife measures
- stronger protections for habitats of high environmental value, including chalk streams
- integration of Local Nature Recovery Strategies into planning decisions
Together, these provisions reinforce the concept that biodiversity gains should be cumulative, not isolated, and that small design choices can produce significant ecological benefits at scale.
Rural and Agricultural Growth: Supported, Not Constrained
A noteworthy dimension of the reforms is the renewed focus on rural productivity. Councils will be required to more proactively support essential agricultural infrastructure, including:
- on-farm reservoirs
- greenhouses and polytunnels
- farm shops and diversification facilities
The aim is to help farmers adapt, innovate and maintain economic resilience. Rural businesses more broadly will also benefit from a shift in planning culture, from resistance to supportive engagement.
Implementation Timeline and Next Steps
The government will publish a full consultation response and implementation timeline early next year. Secondary legislation will be required for some changes, including the 0.2-hectare exemption. Until that legislation is enacted, BNG requirements remain fully in force, and developers must continue following current guidance.
At present, there is no confirmed timetable for this process. Accordingly, existing arrangements will remain in effect until such time as the legislation is enacted.
A parallel consultation on applying BNG to nationally significant infrastructure projects (NSIPs) will launch ahead of implementation in May 2026.
Conclusion: A Calibrated Evolution of BNG
The planning reforms, and particularly the recalibration of BNG around the 0.2-hectare threshold, represent a deliberate evolution rather than a retreat. They address practical issues raised during implementation, maintain the UK’s leadership in biodiversity policy, and ensure that growth and nature recovery remain aligned rather than in conflict.
By focusing regulatory effort where it matters most, on large, high-impact, and strategically significant developments, the government aims to preserve BNG’s environmental integrity while reducing unnecessary burdens on small builders and rural economies.
These changes reinforce a singular principle: well-designed development and nature recovery can, and should, move forward together.
If you need any assistance with Biodiversity Net Gain (BNG), please contact us on 02920 650 331 or enquiries@acerecoogy.co.uk
