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Biodiversity net gain - The final countdown

As the new year looms together with the government’s January 2024 deadline for introducing mandatory biodiversity net gain (BNG), the government has published a raft of long-awaited draft regulations relating to the implementation of BNG, draft BNG planning practice guidance and updates to the existing general guidance on BNG first published in February 2023.  

Biodiversity Gain (Town and Country Planning) (Modifications and Amendments) (England) Regulations 2024

These draft regulations are intended to provide the framework for implementing BNG through amendments to the development management process set out under the Town & Country Planning Act 1990 (TCPA) and associated secondary legislation.

The draft regulations address phasing of BNG for outline and full permission, enabling biodiversity gain plans to be submitted up front and before each phase commences and the requirements for those plans.

The regulations prescribe matters to be included in an overall plan and/or phase plan (subject to there being no irreplaceable habitat forming part of the onsite habitat of the development) to include:

  • information about the steps taken or to be taken to minimise the adverse effect of the development on the biodiversity of the onsite habitat and any other habitat;
  • the pre-development biodiversity value of the onsite habitat;
  • any registered offsite biodiversity gain proposed to be allocated to the development and the biodiversity value of that gain in relation to the development;
  • any biodiversity credits proposed to be purchased for the development;
  • post-development biodiversity value of the onsite habitat (details of how this is dealt with in a s73 application are set out in the legislation).

The draft planning practice guidance provides further detail on the content and approval of outline and phase plans.

Additionally, the draft regulations amend existing development management regulations such that:

  • relevant applications for planning permission must be accompanied by specified information relating to the biodiversity gain condition including details of the onsite habitat and in particular any irreplaceable habitat; and
  • decision notices must include information relevant to the biodiversity gain condition and the register of applications must also include biodiversity gain plan information.  

The transitional provisions in Part 5 clarify that mandatory BNG will not apply to planning applications made before the date on which the regulations come into force.  

The Biodiversity Gain Site Register Regulations 2024

These regulations make provision for a biodiversity gain site register. They set out the requirements for the registration of biodiversity gain sites and for recording the allocation of habitat enhancements on such sites to developments. The regulations require Natural England to:

  • establish and maintain the biodiversity gain site register;
  • deal with applications relating to the registration of biodiversity gain sites;
  • make sure that information in the register is accessible to the public.

Land may be registered in the biodiversity gain site register in relation to a conservation covenant or a section 106 agreement provided that the following conditions are met:

  • the land is in England and the agreement is registered as a local land charge;
  • the agreement must require one or more persons to:
    • carry out works on the land for the purpose of habitat enhancement; and
    • maintain (and monitor the maintenance of) the achieved habitat enhancement for at least 30 years after the completion of those works;
  • the habitat enhancement achieved by the works under the agreement is made available to be allocated (conditionally or unconditionally, and whether for consideration or otherwise) in accordance with the terms of the agreement to one or more developments for which planning permission is granted.

There is a right to appeal to the First-tier Tribunal against rejection of an application, amendment of the register, or removal of an entry from the register.

A fee of £639 is payable for applications to register land on the biodiversity gain site register.  Fees also apply to applications to amend the register and recording the allocation of habitat enhancement.  A fine of £5,000 may be imposed where a person provides false or misleading information in connection with an application to register land.  Details relating to fees and fines are set out in the Biodiversity Gain Site Register (Financial Penalties and Fees) Regulations 2024 currently before parliament.

Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024

Irreplaceable habitats (which already benefit from significant protection under national policy) have a high biodiversity value and are very difficult to recreate, accordingly BNG does not apply as it would be impossible to achieve the requirement to increase biodiversity on top of no net loss.  Irreplaceable habitats must still be recorded in the biodiversity metric, however any impacts to these habitats are unacceptable and will require bespoke compensation to be agreed.  If there are no impacts, enhancement of irreplaceable habitats can contribute to towards a developments BNG requirement.

These regulations modify the application of the biodiversity gain requirement for onsite habitats that meet the definition of ‘irreplaceable habitat’ (which includes: blanket bog, lowland fens, limestone pavements, coastal sand dunes, certain ancient woodland, certain ancient trees and veteran trees, spartina saltmarsh swards, and Mediterranean saltmarsh scrub).  Natural England may issue guidance for identifying whether a habitat falls within the description.

The regulations require that the adverse effect of the development on the biodiversity of the irreplaceable habitat is minimised and “appropriate arrangements” have been made for the purpose of compensating for any impact.  Such arrangements will be appropriate only if “there is a compensation plan in place that secures appropriate compensation relative to the baseline habitat type, and which does not include the use of biodiversity credits”.

Biodiversity Gain Requirements (Exemptions) Regulations 2024

These regulations exempt certain developments from needing to meet the biodiversity gain requirement that would otherwise be imposed as a general condition of planning permission:

  • temporary exemption for small developments where an application for planning permission is made or has been granted before April 2024;
  • development with no impact on priority habitat and where the development impacts (a) less than 25sqm of habitat that has biodiversity value greater than zero; and (b) less than 5m in length of linear habitat (the “de minimis” threshold);
  • householder applications;
  • applications forming part of or ancillary to the high-speed railway transport network;
  • applications for planning permission for development solely or mainly for fulfilling, in whole or in part, the biodiversity gain planning condition which applies in relation to another development;
  • certain self-build and custom-build developments.

BNG - draft planning practice guidance

In support of the regulations, DLUHC has also published its draft BNG planning practice guidance which will come into effect on the date that the regulations come into force and BNG commences.

As such, the guidance is subject to change but has been published at this point to “enable familiarisation”. It covers a wide range of topics and we set out some key points below:

  • The guidance notes that BNG is not just a post permission matter and encourages applicants to “consider BNG early in the development process and factor it into site selection and design”.  Where appropriate, applicants should discuss BNG requirements early in pre-application advice services;
  • The guidance addresses how plan makers should deal with BNG; in particular, the statutory frameworks should be highlighted but policies need not duplicate the detailed provisions.  The guidance confirms it will generally be inappropriate for plans or supplementary documents to be inconsistent with the framework e.g. applying to exempt categories of development or subverting the biodiversity again hierarchy.  However, it acknowledges that plan makers may seek a higher percentage than the 10% required in statute and many authorities around the country are seeking higher levels of BNG;
  • The guidance sets out the information required for a planning application to be validated, including:
    • a statement that the planning permission, if granted, would be subject to the biodiversity condition;
    • the pre-development biodiversity value of the onsite habitat on the date of application including the completed metric calculation tool used showing the calculations;
    • a statement confirming whether the biodiversity value of the onsite habitat is lower on the date of application because of the carrying on of activities (‘degradation’) in which case the value is to be taken as immediately before the carrying on of the activities, and if degradation has taken place supporting evidence of this;
    • a description of any irreplaceable habitat;
    • a plan showing onsite habitat exiting at the date of application (including any irreplaceable habitat).  

In addition to these minimum information requirements, further information may need to be provided in order to assist the consideration of BNG as part of the planning application, in particular where there are particular considerations around significant onsite biodiversity enhancements or use of offsite biodiversity gains.

Where an applicant considers their site exempt, they must set out what exemptions or transitional provisions they are relying on in this regard.  The guidance includes example scenarios to illustrate this;

  • As the biodiversity gain plan is the mechanism to ensure the 10% BNG objective is met, the guidance suggests it would generally be inappropriate for decision-makers to refuse an application on the grounds that the biodiversity gain objective will not be met.  However, as any planning condition must meet the satisfy the six tests (necessary, relevant to planning, relevant to the development, enforceable, precise, and reasonable) the guidance further sets out matters that decision-makers may need to take into account when determining whether the general BNG condition is capable of being discharged successfully, including:
    • the appropriate balance of BNG delivery taking account of the biodiversity gain hierarchy
    • whether the type and location of any significant onsite habitat enhancements proposed for onsite gains are appropriate, taking into account other policies to support biodiversity (including local nature recovery strategies) and other wider objectives; and
    • any other planning conditions which need to be imposed to secure any significant onsite habitat enhancements (including those securing maintenance for at least 30 years after the completion of the development);
  • Where the implications for existing onsite habitats and the contribution to onsite gains is uncertain at the time of planning application (e.g. for outline planning permission where landscaping and layout are reserved matters), the guidance suggests that decision-makers may consider what subsequent approvals will be necessary to ensure significant onsite habitat enhancements are appropriately secured.


There is a lot of information being published within a short space of time and with which developers, landowners, agents/lawyers, and local authorities need to familiarise themselves very quickly.  Defra’s land use planning blog consolidates much of the information [1], as does the government guidance on Understanding BNG which is being frequently updated [2].

The Defra land use blog post of Mike Burke, Natural England’s Head of Sustainable Development on 1 December 2023 [3] looks at the latest BNG templates developed by Natural England – the Habitat Management and Monitoring Plan Template and BNG Habitat Monitoring Report Template (alongside associated guidance also published by Defra on 29 November [4]) which will be of use in practical terms.

The full suite of six SIs to deliver BNG was published on 29 November 2023 and two of which (The Biodiversity Gain (Town and Country Planning) (Consequential Amendments) Regulations 2023 and The Biodiversity Gain Site Register (Financial Penalties and Fees) Regulations 2023) have been laid in in draft in parliament.  The remainder are not being consulted on but were published to support the scrutiny of the two currently before parliament.  Defra notes for each SI that these may yet be further developed or amended prior to finalisation.

The January 2024 deadline for mandatory BNG was confirmed by the government in an updated timetable in September this year [5]; if they intend to meet that deadline, there is very little time to make changes to the draft regulations that have been published.  To date, the implementation of mandatory BNG for small sites and NSIPs remains on track for April 2024 and 2025, respectively.

[1] Biodiversity net gain guidance – what you need to know - Land use: policies and framework (blog.gov.uk)
[2] Understanding biodiversity net gain - GOV.UK (www.gov.uk)
[3] Natural England’s habitat management and monitoring plan templates - Guest Natural England Blog (Mike Burke, Head of Sustainable Development) - Land use: policies and framework
[4] Creating a habitat management and monitoring plan for biodiversity net gain  - GOV.UK (www.gov.uk)
[5] https://www.gov.uk/government/news/biodiversity-net-gain-moves-step-closer-with-timetable-set-out

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