Today's theme of "4 calling birds" apparently refers to "colly birds", the old English term for that beloved songbird the blackbird. According to the results of the RSPB's 2023 Big Garden Bird Watch, the blackbird remains one of the UK's most common garden birds. Unfortunately, others aren't faring so well – the RSPB says that bird numbers have depleted by 38 million in the last 50 years. It therefore seems appropriate for mandatory biodiversity net gain (BNG) to be the topic for today's 2023 Yule Blog post.

In recognition of the nature-depleted state of the nation, mandatory BNG is being introduced in England pursuant to the Environment Act 2021 – see here and here for our previous posts on the reasons for and background to the new requirements. Originally due to come into effect last month for development pursuant to the Town and Country Planning Act 1990 (TCPA), in September the government pushed back the implementation date to January 2024. It was therefore some six months later than originally promised, on 29 November and 1 December 2023, that DLUHC and Defra finally published the full set of regulations and guidance containing all the information that the development industry had been waiting for. Developers, local authorities and landowners should now have all details necessary to prepare for implementation, but there is not much time – according to the Chief Planner's most recent letter to Chief Planning Officers, mandatory BNG is still expected to come into effect in late January 2024.

Given the quantity of material published in past few weeks – which can be found on Defra's Biodiversity Net Gain collection page – there is much for the development industry to process. We can't cover it all here, so instead we take a quick look at what certainty we now have about which developments will be impacted and what we understand the next steps to be.

Which planning permissions will be impacted in January 2024?

We've known for some time that mandatory BNG will not come into effect for nationally significant infrastructure projects until November 2025. Also, we have known for a few months now that only major TCPA development will be deemed to be granted subject to the biodiversity gain condition when the provisions come into force for TCPA development in January 2024 – non-major development will be exempt until a date to be appointed in April 2024.

We now have certainty about what other types of permissions will not be subject to mandatory biodiversity net gain in January 2024.

First of all, mandatory BNG is not retrospective. It will only apply to planning applications which are made after the commencement date. This date will be set out in regulations once they have been passed by Parliament.

Also, owing either to commencement and transitional provisions in the regulations, or to express exemptions, the following permissions will not be subject to mandatory BNG:

  • permissions granted pursuant to an application made before the January 2024 commencement date;
  • retrospective planning permissions (under section 73A of the TCPA);
  • section 73 permissions where either the original permission was granted or the application for the original permission was made before the January 2024 commencement date;
  • planning permissions granted through local development orders, neighbourhood development orders, enforcement appeals, deemed planning permission or permission in principle (although a subsequent technical details consent would be subject to the general biodiversity gain condition);
  • reserved matters approvals (but the relevant outline planning permission will already be subject to mandatory BNG, and the development approved will need to contribute to meeting BNG); and
  • "exempt development", which is exempt pursuant to paragraph 17 of the new Schedule 7A of the TCPA and the draft Biodiversity Gain Requirements (Exemptions) Regulations 2024. Such development includes:
    • until April 2024, non-major development (as noted above);
    • section 73 applications relating to a permission for non-major development where the original permission was subject to the temporary April 2024 exemption;
    • householder development;
    • permitted development rights;
    • "de minimis" developments (ie which do not impact a priority habitat (which are habitats with a high biodiversity value); and impact less than 25 square metres of habitat, or 5 metres of linear habitat (eg hedgerows));
    • self-build and custom-built development (no more than nine dwellings on a site of 0.5 hectares or less, consisting exclusively of self-build or custom housebuilding);
    • urgent Crown development;
    • development of a biodiversity gain site; and
    • development relating to the high-speed railway transport network.

What next?

The government has laid two sets of secondary legislation before Parliament for approval – the draft Biodiversity Gain (Town and Country Planning) (Consequential Amendments) Regulations 2024 and the draft Biodiversity Gain Site Register (Financial Penalties and Fees) Regulations 2024). We are told that, once Parliament has approved these, then the government will lay before Parliament for approval a further four sets of regulations that Defra published in draft on 29 November 2023 – these are: the Biodiversity Gain (Town and Country Planning) (Modifications and Amendments) (England) Regulations 2024, which provide the framework for implementing biodiversity net gain; the Biodiversity Gain Site Register Regulations 2024; the Biodiversity Gain Requirements (Exemptions) Regulations 2024 referred to above; and the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024. At this point, it should become clear on which date we can expect mandatory BNG to come into force for major TCPA development.

There are reports that green groups are still requesting changes to the draft regulations, but it remains to be seen whether the government will act on such representations. In the meantime, developers, landowners and local authorities alike are preparing as best they can for implementation.

Previous posts in our 2023 Yule Blog are here:

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.