Biodiversity Net Gain – Update 2024

Passed into law in November 2021, the Environment Act proposes a new mandatory requirement for new major developments to provide a 10% biodiversity net gain (BNG) from the 12th of February 2024.

What are the current requirements?

Under the current requirements, current national policy sets out that planning should provide BNG where possible as stipulated by the National Planning Policy Framework, however, there is no minimum BNG requirement for Town and Country Planning Act developments.

What has changed with these new requirements?

From the 12th of February 2024, BNG shall be mandatory as set out in the Act.  It applies in England only, and to projects submitted after the 12th of February 2024.

What do new applications have to achieve?
  • Minimum 10% gain required calculated using biodiversity metric and approval of net gain plan
  • Habitat secured for at least 30 years via obligations / conservation covenant
  • Habitat can be delivered on-site, off-site or via statutory biodiversity credits
  • There will be a national register for net gain delivery sites
  • This will also apply to Nationally Significant Infrastructure Projects (NSIPs)
  • This does not apply to marine development
  • This does not change existing legal environmental and wildlife protections
What information needs to be in place to support new applications?
  • A statement setting out whether the site is believed to be subject to the BNG requirements or not – and if not, why not?
  • The biodiversity value of the on-site habitat and the completed biodiversity metric calculation tool
  • A description of any irreplaceable habitat present
  • A plan showing the onsite habitat and any irreplaceable habitat
What information needs to be submitted prior to commencement of a development?

A biodiversity gain plan will need to be submitted, this must include:

  • Information about the steps taken to minimise the adverse effect of the development on the biodiversity of the onsite habitat and any other habitat. This requires the applicant to show how the biodiversity gain hierarchy has been applied
  • The post-development biodiversity value of the development
  • A description of how on-site habitat enhancement will be maintained for at least 30 years
  • A description of how maintenance will be monitored
How can biodiversity net gain be delivered?

There are 3 main delivery mechanisms for BNG as follows:


This includes all land within the boundary of a project. In a planning context, this means within a red line boundary and can be delivered through habitat creation, enhancement via landscaping, and green infrastructure. This is the preferred route and is calculated by establishing a baseline score on the site based on the current habitats on site (this is split between area, quality – relating to distinctiveness, condition and strategic significance of the habitats). Following this, you undertake the same calculation based on the proposed habitat on the final development to give you the post-development score. This will allow you to work out your BNG %.

Off-Site BNG

This is all land outside of the on-site boundary, regardless of ownership and can be delivered off-site through habitat creation, and enhancement via habitat banks with public / private landowners (through a geographical incentive / penalty).

As mentioned above, this can be done on controlled land which is land adjacent to the development site, and can be included on the blue boundary line (additionally owned land) on the planning drawings. It is handled in the metric as “off-site land” but with no penalty attached.

You can also go down the route of Third Party Land, however, a S106 / Conservation Covenant will be required. If TPL is significantly separated from the application site, this can cause the units to be “taxed”.

  • Scenario 1 – Compensation inside Local Planning Authority of site of biodiversity loss – no penalty.
  • Scenario 2 – Compensation outside Local Planning Authority of impact site but in neighbouring Local Planning Authority – 25% unit reduction.
  • Scenario 3 – Compensation outside Local Planning Authority of impact site and beyond neighbouring Local Planning Authority – 50% unit reduction.
Scenario 1 Scenario 2 Scenario 3
Land Required to reach 10% (Hectares) 8.6 (No Penalty) 11.4  (25% Unit Reduction) 17.1   (50% Unit Reduction)

Statutory Credits

BNG can be delivered through largescale habitat projects delivering high value habitats which can also provide long-term nature-based solutions. Credits will be made available for purchase in the future. They are intended for use only where BNG cannot be delivered on-site or off-site via the market, as a last resort.

This means a payment made to external provider who secures habitat units and oversees delivery and monitoring of these. However, these are typically much more costly, however, reduces the risk associated with long-term management.

The below table provides an insight into the expected costs of statutory credits:

How to be successful in delivering BNG on a project

With the new mandatory guidelines for BNG, it is important to take the following steps:

  • Ensure early planning is undertaken by an early appointment of a suitably qualified ecologist
  • Early assessments on your chosen site with surveys being carried out in optimal botanical season (May – September)
  • Develop a high level masterplan with a mitigation hierarchy applied to support design of the masterplan
  • Early modelling and testing to be undertaken to ensure any issues are addressed before the design is finalised
  • Identify long-term responsibilities and agree management measures and ensure feasibility of these
  • Submit an application with the supporting documentation
  • Once permission has been granted, the measures set out in the masterplan can be implemented including ongoing management and monitoring. It is important that the client understands their post-development commitments

For more information, please get in touch with our team via the details below:

01604 859859 

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Posted by: Olivia Smith

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