Biodiversity net gain – things to know before 12 February

07th February 2024

After the recent delay, it has been confirmed that under the Environment Act 2021, all planning permissions granted for major developments in England will have to deliver at least 10% biodiversity net gain from the new date – Monday 12 February 2024.

A couple of months ago, we shared a helpful guide on all things biodiversity net gain, but as time goes on and more details emerge, there is more that you need to be aware of before 12 February. Recently, further guidance was provided on meeting biodiversity net gain requirements offsite – in this case, outside a redline but within a blueline.

Here is some key information from Principal Ecologist and Director of Swift Ecology, Mike Sharp.

Natural England Register of Land

  • To achieve biodiversity net gain offsite, all land intended for this purpose, including any land within the blue line boundary, must be registered on the national sites register, operated by Natural England.  There are some costs and checks associated with registration, details as yet are unknown.
  • The register will go live on the same day as biodiversity net gain becomes statutory on the 12 February 2024.
  • Importantly, the register is not a marketplace to buy units from, and it will not provide contact details of available gain sites.
  • Anyone can search the national sites register to see if any units are available for purchase, but a developer will need to find an offset provider through the private market.
  • Offsite biodiversity gains, including anything in the blue line boundary, will need to be legally secured for 30 years either by a planning obligation e.g. Section 106, or a conservation covenant.

For small developments, these changes will not come into effect until April 2024.

More information on the biodiversity net gain changes can be found on the Understanding Biodiversity Net Gain page.

If the upcoming mandatory biodiversity net gain seems a little overwhelming – our team of trusted professionals can help guide you through the process and keep your development project on track. Get in touch with us on 01865 731700 or email

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