Frequently asked questions.
What is Biodiversity Net Gain and how will this affect UK developers?
Biodiversity Net Gain is a mandatory piece of English legislation, set out in the environment act, UK policy requiring developers to increase biodiversity in new developments . This will affect English developers by necessitating assessments, biodiversity enhancement measures, and proof of net biodiversity gain for planning permission. Buying off site Biodiversity Units can help developers meet their targets, as they represent quantifiable biodiversity improvements made elsewhere, offering a flexible and cost-effective way to achieve compliance.
What is the DEFRA Metric? How is it used to get a BNG Units number? Where can I find out information on this?
The Mandatory DEFRA Metric is used to calculate Biodiversity Net Gain (BNG) Units in England. You can find detailed information about this metric and its usage on the official DEFRA (Department for Environment, Food & Rural Affairs) website or by consulting with relevant authorities for the most up-to-date guidance.
How many BNG (Biodiversity Net Gain) Units will I need ?
The number of Biodiversity Net Gain (BNG) Units you will need for a development project in England depends on various factors, including the size and location of your project and the existing biodiversity on the site. To determine the exact number of BNG Units required for your project, you should consult with local planning authorities or ecological consultants who can assess your project and provide guidance based on the DEFRA Metric.
You may be able to deliver an amount of BNG on site, however, any you are unable to deliver to achieve your net gain requirements can be bought from offsite BNG providers.
What is the Spatial Multiplier element of the BNG legislation?
The Mandatory Biodiversity Metric incentivises habitat delivery close to the development site through a ‘Spatial Risk Multiplier’, which reduces the biodiversity value of habitats delivered further away from the development.
Where a development cannot achieve BNG either wholly or partly onsite, then the developer can achieve the unit shortfall by securing a bespoke site for net gain, or from appropriate sites on the local net gain habitat market from other landowners. These sites will need to meet the criteria of the biodiversity gain sites register. If a shortfall in units required to achieve BNG remains, having explored the onsite option and the off site unit purchase, a developer can purchase statutory biodiversity credits from government as a last resort.
If I buy either an Option for a Unit or pay for a Simple Purchase BNG unit when does this need adding to my planning application?
The requirement to provide BNG units or credits will usually be a condition of section 106 agreement with the local planning authority. To be granted planning permission, you need a net gain solution in place, which demonstrates your baseline and then the post development onsite and offsite mitigation plan.
After planning is granted a developer is required to submit a Biodiversity Gain Plan to get a unique reference number from the unit provider. At this point the Unit Provider Retires the Units from the DEFRA register. This can happen no earlier than the day after planning permission and must be completed prior to the commencement of development
Why are Nattergal’s BNG Units considered to be of the highest integrity?
Nattergal is a company set up specifically to deliver nature recovery at scale and in perpetuity, providing vital benefits for society. Their BNG units contribute to landscape scale rewilding projects delivering huge biodiversity gains through the restoration of natural processes. The team are dedicated to pioneering natural capital funding to deliver large scale rewilding projects founded on data, monitoring and true biodiversity uplift.
Rewilding is a type of nature restoration that takes large scale degraded ecosystems and restores them to nature through restoring natural processes such as large free roaming herbivores and function hydrology. Many BNG projects will be fragmented and on small areas, and although important cannot contribute to true biodiversity uplift at a landscape scale.
BNG contracts are for a minimum of 30 years however Nattergal’s sites will be restored to nature in perpetuity, with BNG forming a critical pillar of the funding required to create these changes. With extensive community engagement and a range of exceptional partners, each site will flourish for generations to come as wilderness thriving with life. As opposed to many other units available, Nattergal’s BNG units contribute to something bigger, at the landscape scale creating true and tangible biodiversity results.
Nattergal is founded by the team behind the Knepp Wildland in West Sussex, with over 20 years of experience delivering nature at scale they are set to provide some of the highest integrity units on the market. This integrity is underpinned not simply by the team and the Defra Metric, but with biodiversity monitoring and university partnerships.
Nattergal’s sites monitor invertebrates, birds, fungi, soils, plants and everything in between using eDNA, sensors and ecologists to demonstrate tangible biodiversity change on top of the metric. This knowledge and research layers on top of the Defra Metric calculation demonstrating that BNG units as part of a landscape scale restoration project delivers true biodiversity gain.
Nattergal’s units are additional, have a positive impact for local communities, are verified against the metric and additional bioidveristy monitoring, and are part of something much bigger – landscape scale change.
What are the key components of mandatory BNG?
Amends Town & Country Planning Act (TCPA);
Minimum 10% gain required calculated using the Biodiversity Metric & approval of a biodiversity gain plan;
Habitat secured for at least 30 years via planning obligations or conservation covenants;
Delivered on-site, off-site or via a new statutory biodiversity credits scheme; and
National register for net gain delivery sites.
It does not change existing legal protections for important habitats and wildlife species. It maintains the mitigation hierarchy of avoid impacts first, then mitigate and only compensate as a last resort. It will apply to Nationally Significant Infrastructure Projects (NSIPs) but not marine development.
When will 10% biodiversity net gain become mandatory? Why is there a delay for mandatory BNG for small sites until April 2024?
The mandatory requirement came into place on February 12th 2024 for all but exemptions and small sites. The Government's response to the 2018 consultation on net gain set out that there would be a 2 year implementation period for mandatory BNG once the Environment Bill received Royal Assent and became the Act (which happened on 9 November 2021). The Government’s 2023 response to the 2022 BNG consultation set out that the transition period for small sites will be extended to April 2024. The delay to implementing BNG for small sites is to lessen initial burdens and allow a longer period for developers and local planning authorities to adapt and prepare for the high volume for minor applications. The Act includes provision for secondary legislation to set a date for the requirement to come into force.
Small sites are defined as:
(i) For residential: where the number of dwellings to be provided is between one and nine inclusive on a site having an area of less than one hectare, or where the number of dwellings to be provided is not known, a site area of less than 0.5 hectares.
(ii) For non-residential: where the floor space to be created is less than 1,000 square metres OR where the site area is less than one hectare.
What is the Biodiversity Metric?
Demonstrating BNG requires an approach to measuring biodiversity. The DEFRA Biodiversity Metric is a habitat-based approach to determining a proxy biodiversity value developed by Natural England. The Biodiversity Metric is designed to provide ecologists, developers, planners and other interested parties with a means of assessing changes in biodiversity value (losses or gains) brought about by development or changes in land management. Mandatory BNG will require use of the latest version of the Biodiversity Metric. The current version is the Mandatory Biodiversity Metric.
What is on-site and what is off-site for BNG?
‘On-site’ includes all land within the boundary of a project. In a planning context, this usually means within a red line boundary.
‘Off-site’ is all land outside of the on-site boundary, regardless of ownership.
Note that on-site does not include land within the ‘blue line’ boundary.
How long does off site BNG have to be maintained
If the developer is using off-site units, this must be legally secured for at least 30 years, and registered, before they can count towards BNG. Habitat creation or enhancements do not count towards BNG if required for restocking conditions relating to a tree-felling licence, marine licensing, or remediation under the environmental damage regime.
What is a Biodiversity Gain Plan?
The Biodiversity Gain Plan is a document which sets out how a development will deliver biodiversity net gain and allows the planning authority to check whether the proposals meet the biodiversity gain objective.
The Environment Act sets out that development subject to mandatory BNG will be required to submit a biodiversity gain Management Plan for local planning authority approval
As part of completing the BGP, a developer will have to give details of the development and a proposed BNG Solution. If the provider chooses an offsite BNG Solution they will need a unique reference number which corresponds with the DEFRA register.
Is BNG not going to be mandatory in the rest of Britain?
The Environment Act has an 'extent' section which sets out which parts of the Act apply across Britain. The BNG provisions only apply to England via Schedule 14. CIEEM have just published a briefing note for Scotland see: Biodiversity Net Gain in Scotland: Briefing Note for Local Planning Authorities.
What is the national biodiversity credits scheme?
The Environment Act makes provision for the Secretary of State to set up a system of statutory biodiversity credits that will be invested in habitat creation. The biodiversity credits scheme allows the UK government to sell biodiversity credits to developers if the required biodiversity net gains cannot be achieved on-site or through the off-site market. The price of biodiversity credits will be set higher than prices for equivalent biodiversity gain on the market and DEFRA published indicative credit prices on 27 July 2023. Natural England will sell statutory biodiversity credits on behalf of the Secretary of State. An accessible and user-friendly digital sales platform is currently being developed and tested.