Biodiversity net gain (BNG) is a way of creating and improving natural habitats. BNG makes sure development has a measurably positive impact ('net gain') on biodiversity, compared to what was there before development. It does this by requiring developers to increase biodiversity by a minimum of 10%.

It is in addition to existing legislation for protected habitats and species, but is also a mandatory requirement in the Environment Act 2021.

Measurement

Natural England has published a biodiversity metric tool, which uses biodiversity units to measure the value of a habitat. It calculates units based on the size, distinctiveness, condition and strategic significance of the habitat.

You can then use these units as credits to off-set biodiversity loss your development may cause.

You can gain units either on-site or off-site. You can gain on-site units by improving the habitat on-site via landscaping and green infrastructure. If you are unable to improve biodiversity directly on-site, you can do it on other land you already own, or in partnership with public or private landowners, to gain off-site units.

If you can’t gain on-site or off-site units, you need to buy statutory biodiversity credits from the government. This must be a last resort. The government will use the revenue to invest in habitat creation in England.  

How this will affect your planning application

The BNG requirements will come in under a phased process. It will apply to:

  • major developments and Priority Habitat Sites from Monday 12 February 2024
  • small sites from Tuesday 2 April 2024
  • Nationally Significant Infrastructure Projects (NSIPs) from November 2025

An application will be exempt if it is:

  • permitted development
  • a householder application
  • a development impacting habitat of an area below a threshold of 25m2, or 5m for linear habitats (De Minimis)
  • a biodiversity gain site
  • a small scale self-build and custom housebuilding

How we will secure BNG

We will normally use planning conditions to secure on-site habitat enhancements. You will need to secure and maintain the enhancements for at least 30 years. Other potential conditions could include monitoring and reporting arrangements.

We are likely to use a legal agreement (such as a Section 106 agreement) to secure any off-site enhancements, including their management and monitoring.

What you need to submit

All developers must submit a:

  • Biodiversity Net Gain Statement
  • site plan, drawn to an identified scale marked with the direction of north, showing on-site habitat existing on the date of application (or an earlier date), including any irreplaceable habitat
  • completed biodiversity metric (as an Excel-file type), for both pre-development and post-development
  • a draft BNG plan

You have to submit final a Biodiversity Gain Plan, which we must approve, before you start work. You need to provide us with a draft version of the plan with your application.

You also need to submit a Habitat Management and Monitoring Plan (HMMP), to show how you will manage and monitor the biodiversity enhancements for at least 30 years.

You can download a:

which you need to complete and submit as part of your application.

You must submit both plans through the Discharge of Conditions application process.

Further information

You can find more details about BNG on GOV.UK.

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