CIVITY NGE Blog

From February 2024, mandatory Biodiversity Net Gain (BNG) became a legal requirement for most planning applications under the Environment Act 2021. While the general rule is that all major developments must deliver at least a 10% net gain in biodiversity, there are defined exemptions and carve-outs that may apply in certain cases. Understanding whether your development site is exempt is critical for developers, planners, and landowners navigating the evolving landscape of biodiversity net gain regulations. This article outlines a structured checklist based on the latest BNG legislation, statutory guidance, and planning practice guidance, enabling you to determine whether your site is likely to qualify for an exemption from BNG requirements. 1. Does Your Development Fall into a Statutory Exempt Category? BNG applies to most planning permissions granted under the Town and Country Planning Act 1990, but specific exemptions are set out in regulation and clarified by DEFRA’s guidance. Check if your proposal meets any of the following criteria: Householder development: Applications made by householders, including extensions, conservatories, loft conversions, and similar works to an existing dwelling. These are defined under article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015. Permitted development: Developments granted planning permission by a development order (such as certain agricultural buildings or changes of use) without the need for a formal application. Development solely to enhance biodiversity: If the proposed development is carried out mainly to fulfil the BNG requirement for another development (i.e., the creation of a biodiversity gain site), it is exempt. High-speed rail transport network: Exemptions apply to works forming part of or ancillary to the network defined in the High Speed Rail (Preparation) Act 2013. Urgent Crown development: These are exempt under provisions of the Environment Act 2021. Irreplaceable habitats: Sites containing irreplaceable habitats (e.g., ancient woodland, lowland fens) are treated differently. BNG is not required, but these habitats trigger their own mitigation obligations under the biodiversity gain hierarchy. If your scheme matches any of these, it may be exempt from BNG. However, careful interpretation of the biodiversity net gain regulations and supporting planning guidance is still needed. 2. Is the Site Below the De Minimis Threshold? A de minimis exemption applies where the development site: Impacts less than 25 square metres (5m x 5m) of on-site non-priority habitat, and Impacts less than 5 metres of linear habitat (such as a hedgerow), and Does not impact any priority habitat. A habitat is ‘impacted’ if the development decreases its biodiversity value. Sites that meet this threshold are exempt but must still provide sufficient evidence, such as a habitat survey, to demonstrate compliance. 3. Was Planning Permission Granted Before the Relevant Date? BNG only applies to planning permissions granted after 12 February 2024 for major developments and after 2 April 2024 for small sites. Therefore, you may be exempt from BNG if: Your planning application was submitted and approved before the relevant cut-off date; A phased development or outline permission was granted with reserved matters before the deadline; The development is authorised under a local development order or neighbourhood development order adopted before BNG came into force. This includes variations to existing permissions that remain under transitional arrangements. In these cases, biodiversity gain plans and statutory biodiversity metric calculations are not required. 4. Is Your Project a Custom or Self-Build? Small-scale self-build and custom housebuilding developments may qualify for BNG relief. According to the regulations and DEFRA guidance, such sites are exempt if they: Consist of no more than 9 dwellings; Are on a site of no more than 0.5 hectares; Consist exclusively of dwellings that meet the legal definition of self-build or custom housebuilding under section 1(A1) of the Self-build and Custom Housebuilding Act 2015. Where these conditions are satisfied, developers are not required to submit a biodiversity gain plan or demonstrate uplift using the biodiversity metric. 5. Does the Site Support Existing High-Value Habitats? While not an exemption, the presence of irreplaceable habitat or onsite priority habitat affects how BNG rules are applied. Developments impacting such features: Follow the mitigation hierarchy, avoiding harm where possible; Demonstrate significant enhancement or compensation where unavoidable; Consult with the local planning authority or relevant oversight body. These habitats are not covered by the statutory biodiversity metric in the same way as other habitats, and bespoke ecological input will be required. 6. Are You Delivering BNG On Another Site You Own? Some developers seek to deliver their own BNG offsite on land they own or control. This does not exempt you from BNG rules, but additional requirements apply: You must register the land as a biodiversity gain site with Natural England. Submit a legally binding agreement (via Section 106 or Conservation Covenant); Prepare a compliant biodiversity gain plan showing how you meet the biodiversity gain objective. Note: Civity does not support developer-led offsite habitat banks. We only supply pre-registered BNG units from landowner sites through our landbank. 7. Are You Only Enhancing Biodiversity Without Other Development? If your project’s sole purpose is to enhance the natural environment, for example, through habitat creation, restoration, or biodiversity enhancements, and it does not include any infrastructure or buildings, it may be exempt from mandatory BNG. However: Planning authorities may still require submission of clear site plans. You may need to provide details of post-development management and funding , Ongoing management obligations may still apply via legal agreements. This exemption is not always straightforward and depends on your proposed site plans and planning context. 8. Does the Site Comprise Only Hardstanding or Low-Value Habitat? Developments on previously developed land, such as existing car parks, yards or buildings, can have low or zero pre-development biodiversity value. While this doesn’t automatically exempt the development, it may: Reduce your required uplift target under the biodiversity gain condition; Simplify your biodiversity gain plan and metric assessment. In some cases, sites with zero pre-development onsite habitat may have lower obligations but will still need to use the statutory biodiversity metric to confirm the baseline. A Practical Exemption Checklist Use the following to assess if your site may be exempt from BNG: Is the proposal: A householder development? Permitted development? Solely for biodiversity enhancements? Covered by a development order? Part of the high-speed rail network? An urgent Crown development? Does the site: Impact less than 25 m² of non-priority habitat? Affect under 5m of linear habitat? Contain priority habitat or irreplaceable habitat? Has planning permission already been granted before? 12 February 2024 (major development)? 2 April 2024 (small sites)? Is it a: Self-build or custom-build development of 9 or fewer dwellings? On less than 0.5 ha? Are you planning to: Enhance biodiversity only (with no buildings)? Develop a site of low pre-development biodiversity? Offset on land you already own? Answering ‘yes’ to any of the above may indicate exemption from BNG, but always check the latest further guidance from DEFRA and your local planning authority. At Civity… We assist with the relevant sections of the biodiversity gain plan and provide the associated legal mechanisms (e.g., Section 106 or Conservation Covenant) to meet the biodiversity gain objective via offsetting onto our habitat banks. We do not calculate the pre-development or post-development value of the development site; that remains the responsibility of your ecologist. Nor do we support DIY offsite delivery projects. Our role is to provide ready-to-use biodiversity units that comply with all BNG rules. Looking Ahead As biodiversity net gain becomes embedded into the UK planning system, understanding exemptions is just as important as understanding obligations. By using the checklist above, you can identify whether your development site qualifies for an exemption, and if not, you’ll be better prepared to meet the requirements through a transparent, compliant approach. For developers seeking offsite units or landowners interested in registering a site, Civity provides trusted, expert support aligned with the latest BNG regulations and national planning policy.

Under the Environment Act, developers must achieve biodiversity net gain (BNG) on all qualifying development projects. This means delivering a 10% net gain in biodiversity value compared to the site’s baseline, using the statutory biodiversity metric or small sites metric. This blog outlines practical biodiversity net gain examples: how developers are meeting the 10% requirement. Whether through on-site habitat improvements, off-site biodiversity units, or, in rare cases, statutory biodiversity credits, we explain how developers are aligning with the biodiversity net gain regulations and how Civity helps navigate the process. Understanding the 10% Net Gain Requirement To deliver biodiversity net gain, developers must: Assess the baseline biodiversity units using the statutory biodiversity metric tool or the small sites metric. Compare pre-development biodiversity value with the proposed post-development value (after habitat creation, enhancement, or retention). Achieve a minimum 10% uplift in units via a legally secured biodiversity gain plan. Off-site biodiversity gains must be secured through a legal agreement—either a Section 106 agreement with the Local Planning Authority or a Conservation Covenant with a Responsible Body. On-site gains do not require registration but may still require a legal agreement and must be delivered and maintained in line with the approved Biodiversity Gain Plan and local planning conditions. Ensure a minimum of 30 years of land management and monitoring to preserve those gains.   This process applies to the majority of full planning permissions granted after February 2024, including minor developments and small sites. Example 1: On-Site Habitat Creation and Enhancement Description Some development sites are well-suited to achieve BNG entirely on site, especially where space, context, and habitat baseline allow. This is often the case for low-density housing schemes or brownfield sites with low existing biodiversity. How Developers Achieve On-Site Gains Enhance existing features such modified grassland, ponds, or on-site linear habitats such as hedgerows Integrate tree planting, wildflower meadows, green infrastructure, and SuDS. Apply the mitigation hierarchy to retain irreplaceable or sensitive habitats and build around them. Outcome 100% of the gain is delivered on the developer’s own land within the red line boundary. No need to source off-site compensation (i.e. biodiversity units)  Full alignment with the biodiversity gain hierarchy, maximising the natural environment benefits at the site itself. A legal agreement may still be needed to secure on-site gains. Good Practice Tip Achieve on-site gains early by integrating biodiversity into design from the outset. Developers should coordinate ecological advice, drainage strategies and access public realm design to enhance the on-site habitat network. Example 2: Combining On-Site and Off-Site Biodiversity Gains Description Where space is limited or development intensity is high, it’s not always possible to meet the full 10% on site. In these cases, developers often blend on-site biodiversity gains with off-site BNG purchases from third-party providers. How Developers Balance the Requirement Deliver as much as possible on site, such as enhancing on-site habitats, creating small wildflower areas, planting trees and hedgerows or restoring existing biodiversity assets. Source the remaining units via off-site biodiversity gains from a registered gain site on the biodiversity gain site register. Outcome A proportion of the gain is delivered on site, with the remaining delivered through purchase of off-site biodiversity units.  The developer meets their mandatory biodiversity net gain obligation without compromising build density or viability. The off-site component aligns with wider national (ideally local) conservation efforts. Good Practice Tip Work with a specialist like Civity to secure units from registered gain sites. We ensure the off-site delivery is legitimate, auditable, and aligned with the developer’s biodiversity metric and gain plan. Example 3: Using Statutory Biodiversity Credits (Last Resort) Description In exceptional cases, developers may be unable to meet BNG on or off site. This may occur where there are no suitable off-site BNG suppliers. Statutory Credit Purchase: Requirements and Evidence Before purchasing statutory biodiversity credits from the government, developers must first demonstrate that on-site and off-site options have been fully explored and are not deliverable. This includes: A clear explanation of why delivering the full 10% Biodiversity Net Gain (BNG) requirement is not feasible within the boundary of the development site. Evidence that alternative off-site solutions have been sought and are unavailable.   To meet this requirement, the Biodiversity Gain Plan must include proof that the developer has approached at least three separate off-site unit providers – this may include habitat banks, specialist brokers, or national trading platforms. Acceptable forms of evidence might include: Emails or letters showing engagement with unit providers. Screenshots from trading platforms demonstrating no matching units. Downloaded reports or search logs confirming no availability of required habitat types and locations.   Only once all reasonable efforts to secure on-site and off-site units have been documented can a developer proceed to purchase statutory biodiversity credits from Natural England to address any outstanding shortfall. The use of statutory credits must be clearly recorded in the Biodiversity Gain Plan and will be subject to review and approval by the Local Planning Authority. Outcome Statutory credits are used to reach the 10% uplift. Typically more expensive than other options and subject to scrutiny. Acceptable only if consistent with biodiversity net gain legislation and subject to the biodiversity gain condition in the planning permission. Good Practice Tip Statutory credits should only be used once off-site compensation and on-site enhancement options are proven infeasible. Planning authorities will require documentation to justify this route. Supporting Developers to Achieve Biodiversity Net Gain At Civity, we help developers meet their biodiversity net gain requirements in a compliant and efficient way. We: Review the submitted biodiversity metric calculations. Quote for the correct number and types of units – providing our most cost-effective option.  Help quantify and allocate off-site biodiversity units from our registered habitat banks. Assist in completing the biodiversity net gain plan, including referencing relevant local planning authority, site location, unit breakdowns and legal agreements. We work consultatively with your ecologist, planning consultant and legal advisor to ensure seamless integration of BNG into your wider development proposals. Delivering BNG in Practice These biodiversity net gain examples of how developers are meeting the 10% requirement demonstrate that BNG is achievable across a wide range of development sites. Key takeaways: Create biodiversity on site wherever possible Source off-site biodiversity units responsibly.  Only purchase biodiversity credits where no other option is feasible. Align with BNG on-site best practices and your relevant local planning authority’s expectations. With the right technical input, legal oversight and delivery support, developers can consistently achieve biodiversity net gain. To explore how Civity can support your planning application, secure off-site units, or assist with  your biodiversity net gain plan, please get in touch.

Registration of a gain site on the Biodiversity Gain Site Register is a critical step under the mandatory Biodiversity Net Gain (BNG) framework. Whether you are a landowner seeking to create a site that can generate biodiversity units or a developer analysing the availability of off‑site biodiversity units, understanding the process, including costs, required forms and common pitfalls, is essential. Civity supports landowners navigating this regime, aligned with the statutory requirements and best practice. Why register a site? Registering land on the Biodiversity Gain Site Register enables a land parcel to become eligible to deliver units that a development subject to BNG can use. Specifically: A development site must deliver a minimum 10% net gain in biodiversity value compared with the pre-development biodiversity value (using the statutory biodiversity metric tool). Where on-site habitat enhancements cannot deliver sufficient biodiversity units to meet the 10% net gain requirement, developers must rely on off-site gains. These units must be sourced from a biodiversity gain site that is both legally secured (via a Section 106 agreement or Conservation Covenant) and formally registered on Natural England’s Biodiversity Gain Site Register. The register supports transparency in the biodiversity gain market by recording where habitat creation or enhancement will occur, ensuring units are not double counted. Once a gain site is registered, the landowner may sell biodiversity units, and the developer may use them to meet their biodiversity net gain requirements. At Civity we advise both sides, landowners on the registration process and developers on sourcing units from registered sites, while ensuring alignment with the biodiversity gain plan and associated obligations. Key prerequisites: What you must have before applying Before submitting your application to register a gain site, you must ensure the following are in place: Proof of land ownership (title deeds or valid lease/authorisation) for the land you propose to register. A map setting out the boundary of the site.  A legal agreement securing the site for at least 30 years, either a Section 106 (with the relevant local planning authority) or a conservation covenant with a responsible body. A completed calculation using the statutory biodiversity metric (or metric tool) showing existing habitat (pre‑development biodiversity value) and proposed habitat (post‑development biodiversity) for the gain site. A Habitat Management and Monitoring Plan (HMMP) covering the management and monitoring of the habitat for the long‑term (30 years at least). A local land‑charge search certificate (so the legal agreement is registered). Application process, forms & costs Forms and submission There is a dedicated application form for registering a gain site and a separate (or combined) form if you are also allocating off‑site biodiversity units from your gain site to a development. The form requires details of the applicant (landowner or agent), the site (grid reference, hectares or length for linear habitats), the legal agreement, habitat information per metric row (creation or enhancement), and the development details if allocation to a development is sought. Supporting documentation must be submitted when requested (within a specified period), and you must pay the registration fee within 28 days of the request. Costs The registration fee for a gain site under the current guidance is £639. Additional costs you should budget for (not fees to the government but necessary costs) include: Ecological surveys and metric tool calculation (pre‑development and projected post‑development values) Legal fees for drafting the legal agreement (Section 106 or conservation covenant) Preparation of the HMMP and associated monitoring plan Land‑charge search and mapping costs Long‑term habitat management and monitoring (30‑year horizon) Ongoing costs for brokering units and allocating on the register Post‑submission Once you submit the application and payment, you will be notified within six weeks whether your application is accepted or if further information is required. If accepted, you will receive a unique gain site reference number, and your site will appear on the public register. At Civity: How we support you We provide tailored support for both landowners and developers in respect of the Biodiversity Gain Site Register and related BNG obligations. For landowners: We provide a free desk‑based assessment, support preparation of the metric calculation, liaise on the legal agreement (Section 106 / conservation covenant), develop the HMMP, and submit the registration documentation on your behalf. We work alongside the landowner throughout the entirety of the scheme as their monitoring ecologist. Civity also broker and pool the unit sales. For developers: We provide off-site biodiversity units from already registered sites, verify the metric calculations and allocation, and assist in completing the biodiversity gain plan.This ensures the process is efficient, aligned with regulation and free from surprise delays or pitfalls. Conclusion Registering a biodiversity gain site is a non‑optional component of the BNG framework for off‑site units. The process includes the legal securing of land, metric calculation, HMMP preparation, form submission and payment of the fee. Landowners who register sites open the opportunity to sell biodiversity units, while developers gain access to compliant units and support for their biodiversity net gain plan. By understanding the costs, forms and common pitfalls, you are far better equipped to proceed with confidence. If you are considering registering a site, or if you are a developer seeking to allocate or purchase units, we recommend contacting our team at Civity for an initial consultation and next-step outline.