Biodiversity Net Gain (BNG) is a new legal requirement for most new developments in England.
At its heart, BNG is an approach to development and land management that ensures projects have a positive impact on biodiversity. The idea is that any development should not only avoid harm to nature but should also help restore and improve the natural environment, making it measurably better than before.
BNG was introduced via the Environment Act 2021 and became effective in February 2024. In order to get planning permission, developers will now have to submit:
Together, these documents evaluate the land's habitat value and outline a plan to increase biodiversity by at least 10% over 30 years.
This new approach aims to address biodiversity loss caused by human actions. It ensures new builds improve their biodiversity value or generate a biodiversity uplift.
Achieve Biodiversity Net Gain in three ways.
Developers, Local Planning Authorities, and Landowners/Homeowners are all included in the rollout. The Environment Act requires them to help the UK achieve the Biodiversity Net Gain goals.
As set out above, developers need to prove that their project will enhance biodiversity or achieve net gain. Development proposals must now include a completed metric sheet and habitat plan, along with a Biodiversity Gain Plan (or BGP for short).
There are three ways to prove and include biodiversity value in a development proposal:
Creating on-site environmental benefits that enhance the habitat value.
Examples of this may be:
enhancing on-site habitats under the terms of the biodiversity metric,
or creating new habitats that are appropriate for the site, such as building appropriate green infrastructure.
By doing this, developers will improve nature's quality, protect key habitats, add ecological features to new projects, and provide other environmental benefits! They will need to make sure that the on-site habitat enhancements are appropriate and sustainable for the next 30 years and should take steps to ensure that the enhancements are delivered.
Using approved and registered off-site biodiversity units.
If it is not possible to secure the necessary on-site gains, then off-site units can be allocated to the site. These can either be units:
In either case, the Local Planning Authority needs to approve the units, they need to be sustainable for 30 years and registered in the Natural England register.
Read more on biodiversity units here.
Obtaining statutory biodiversity credits (only applicable in special cases).
This third option is a last resort to reach biodiversity net gain mandates in a few (rare) cases. Particularly, when developers are unable to achieve BNG minimum requirements via either on-site or off-site solutions.
If these conditions are proven true, credits can be bought from the Secretary of State. All money from these credits will be used only for improving habitats.
Read more on biodiversity credits here. How will BNG impact our future?
New analysis reveals that the Government’s Biodiversity Net Gain (BNG) laws will secure over 15,000 hectares, or 23,500 football pitches, worth of biodiversity in England each year.
See how we calculated this
The Environment Act 2021 mandates a minimum of 10% BNG.
The Environment Act 2021 mandates the key components for Biodiversity Net Gain for all new developments (
with very few exceptions). It revises the Town & Country Planning Act 1990 and stipulates the following modifications:
A mandatory increase of at least 10% in biodiversity. This gain is calculated using the standardised
Biodiversity Metric.
Newly developed habitats must be protected for a minimum duration of 30 years. Planning obligations or conservation covenants ensure this.
BNG can be achieved either on-site, off-site, or through official biodiversity credits. However, the
mitigation hierarchy states that restorative work should always be as close as possible to the point of impact.
The Act introduces a national register for tracking off-site net gain delivery sites.
The Act maintains existing legal protections for key habitats and wildlife species.
Following the mitigation hierarchy involves prioritising avoiding major environmental impacts. If avoidance is not possible, the next step is to mitigate these impacts. Compensatory measures are the last step.
The Act's provisions apply to many types of development including Nationally Significant Infrastructure Projects (NSIPs).
Local Planning Authorities must now legally check each planning application for BNG compliance. As the planning authority, local councils are, in effect, now responsible for preventing biodiversity loss in all new developments.
Streamlining Biodiversity Net Gain with Joe’s Blooms
KADS Design Ltd faced a time-sensitive project: designing new garages in Bulkington, Warwickshire while the Local Planning Authority (LPA) mandated BNG compliance.
Small Site Metric Process
total area and less than 1,000m2 new commercial floorspace
on-site biodiversity net gain
The Solution:
Leveraging the Small Site Metric (SSM) Process:
Site qualifications: Under 10,000m2 total area and less than 1,000m2 new commercial floorspace
Advantage: Expedited process without external ecologists or consultants
Utilising Joe’s Blooms Biodiversity Net Gain Tool:
Site Mapping: KADS easily mapped existing habitats (sealed surface and vacant/derelict land)
Impact Assessment: Evaluated biodiversity impact of original plans
Collaborative Redesign: Conducted same-day site visit with the client
Iterative Design: Used the tool to adapt plans, incorporating trees and high-quality grassland habitats
The Results:
Rapid Turnaround: New, BNG-compliant design created within hours
Exceeded Requirements: Achieved over 10% on-site biodiversity gain
Mitigation Hierarchy Compliance: Fully aligned with environmental principles
Cost-Effective: Avoided expensive consultations and delays
Streamlined Submission: Quickly prepared and submitted all necessary documentation to the LPA
BNG principles for planning applications and development.
BNG is not just a legal requirement - it’s an approach. One that aims to prevent further biodiversity loss by protecting local habitats, engaging stakeholders, and aligning with local and national
conservation aims. Maintaining and reversing biodiversity loss isn’t just about following the new law, it’s about embracing best practices too.
CIEEM,
IEMA and
CIRIA have developed 10 principles to guide effective and lasting Biodiversity Net Gain.
Apply the
Mitigation Hierarchy. Avoid environmental harm, followed by minimising impacts, then remediation. Where harm is unavoidable, compensate through environmental enhancements.
Avoid losing
irreplaceable biodiversity. Protect habitats and species that cannot be replaced or replicated elsewhere.
Be inclusive and fair. Involve and consider all stakeholders, ensuring fair distribution of environmental benefits and burdens.
Address risks. Anticipate and manage potential negative impacts on biodiversity throughout the project lifecycle.
Make a measurable Net Gain contribution, ensuring gains outweigh losses.
Be additional. BNG initiatives should enhance, not replace, existing biodiversity commitments and regulations.
Aim for high-quality, sustainable ecological improvements that support a diverse range of species and habitats.
Develop long-term, sustainable benefits for biodiversity, leaving a positive impact for future generations.
Combine BNG with wider environmental goals to support both biodiversity and other ecological aims.
Be transparent and maintain openness in all BNG processes and decisions.
Who is exempt from Biodiversity Net Gain?
The UK Government has listed a
small number of exemptions from the BNG law. It’s worth saying that these exemptions are few and far between. BNG is intended to be a universal policy, and it’s always better to err on the side of complying than trying to avoid it. With that said, let’s look at the main exemptions:
Sites specifically enhanced to create off-site units, termed biodiversity gain sites, are exempt. These sites are already geared towards enhancing biodiversity.
Development related to household applications also falls under the exemptions. Of course, you can always undertake BNG anyway and there are a number of other things you can do to
increase biodiversity in your home.
Small-scale self-build and custom housebuilding projects. However, you must make sure that you meet the specifications set out in the relevant laws.
You can read more about the De Minimis exemption
here, or check whether you’re exempt
here.
Compliance and Planning Ahead
Understanding BNG and its integration from LPA, Landowner, and Developer viewpoints can help align new projects with local conservation and changing rules.
Compliance with local councils and other planning authorities.
BNG lets councils think broadly and holistically, connecting it to other services. For councils tackling climate and ecological emergencies, BNG offers concrete action. It's a way to plan local nature's future, benefiting local communities.
Compliance with Local Nature Recovery Strategies.
Local Nature Recovery Strategies (LNRS) are also key. They enable collaboration with nearby authorities and involve various groups, such as communities, farmers, landowners etc, in creating and benefiting from BNG.
Go up
Our experts continually monitor the BNG space, and we update our articles when new information becomes available.
Feb 3, 2024
Reviewed and edited by Oliver Lewis.
Mar 3, 2023
Written by Oliver Lewis.
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