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Biodiversity Net Gain Requirements in Nottingham City

Biodiversity Net Gain (BNG) is a process by which development or land management aims to leave the natural environment in a measurably better state than it was prior to the development or management action taking place.

Under the Environment Act 2021 and its associated Statutory Instruments (Regulations), it is now mandatory for most major developments, and for many smaller developments to achieve a minimum of 10% Net Gain. This is measured using a standardised metric calculation undertaken by a competent person and is based upon the onsite habitats present pre-development and those that are to be created or enhanced.’

Please use the Statutory biodiversity metric tools and guides - GOV.UK (

Nottingham City Council is currently in the process of updating the adopted Biodiversity Supplementary Planning Document (SPD) to provide clarity and any necessary locally specific information about BNG. The information provided on this web page is to signpost developers, applicants and their advisors to relevant national sources of information as well as provide any locally-led specifics in advance of the availability of the updated SPD.

Planning applications that are exempt from requiring mandatory BNG include (but are not limited to):

  • S73 applications for planning applications approved prior to BNG becoming mandatory
  • Householder applications
  • Permitted development
  • De-minimis applications – those that have an impact on an area of habitat below 25m2 (such as 5m x 5m) and below 5m in length for linear habitats, and do not affect priority habitat at all.

For a full list and explanation of exemptions to mandatory BNG see Biodiversity net gain: exempt developments - GOV.UK (

There is a large amount of information available online from the Government (specifically DLUHC and Defra).

Some useful links are provided below:

Biodiversity net gain - GOV.UK (

The Planning Advisory Service has published guidance for Local Planning Authorities (LPAs) which may also be of interest:

Under the Regulations the mandatory Biodiversity Gain Plan is not required until after planning permission has been granted, as it is required to be approved by the LPA to discharge the General Biodiversity Gain Condition (GBGC; which is a pre-commencement condition). Planning permission must be in place before the Biodiversity Gain Plan can be finalised, including confirmation that any offsite biodiversity units have been legally secured or statutory credits purchased.

The template for this mandatory document is provided here Biodiversity gain plan - GOV.UK (

However, in order to validate and determine any non-exempt planning application, Nottingham City Council’s Local Planning Authority needs to assess whether the development is capable of discharging the GBGC and achieving at least 10% net gain.

The LPA must have confidence in the correct characterisation and valuation of pre- and post- development habitats, be sure that the biodiversity gain hierarchy (and mitigation hierarchy) have been adhered to, as well as being confident that habitat management and monitoring of significant onsite and any offsite habitat will be feasible, appropriate and legally secured for 30 years. BNG must therefore be considered early on in the planning process and cannot be left until post-determination. It should be used to guide site selection and inform development design.

Minimum National Requirements

The minimum information required for validation is set out in Article 7 of The Town and Country Planning (Development Management Procedure) (England) Order 2015, and is summarised as follows:

  • A statement as to whether the applicant believes that planning permission, if granted, would be subject to the biodiversity gain condition (including the reason why, if not subject to the condition);
  • The pre-development biodiversity value of the onsite habitat on the date of application (or an earlier date) including the completed metric calculation tool(s) used showing the calculations, the publication date and version of the biodiversity metric used to calculate that value;
  • Where the applicant wishes to use an earlier date, the proposed earlier date and the reasons for proposing that date;
  • A statement confirming whether the biodiversity value of the onsite habitat is lower on the date of application (or an earlier date) 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 (as set out in column 1 of the Schedule to the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations [2024]) on the land to which the application relates, that exists on the date of application, (or an earlier date); and
  • A plan, drawn to an identified scale which must show the direction of North, showing onsite habitat existing on the date of application (or and earlier date), including any irreplaceable habitat.

Additional Local Requirements for Validation 

In addition to the above minimum mandatory requirements, Nottingham City Council require for validation the following: 

-   Statutory metric (in Excel format) to include forecast post-development habitat values and calculations and to be accompanied by habitat condition assessments for all pre-development habitats;
-    BNG Statement setting out: 

  • How the development is going to achieve 10% or more net gain,
  • How the Mitigation Hierarchy and the Biodiversity Gain Hierarchy have been applied and what steps have been taken to minimise adverse effects on biodiversity,
  • Details of any offsite habitats required to be created and/or enhanced, including offsite baseline habitat assessments, metric calculations and condition assessments, a plan showing habitats and information on initial agreement terms with offsite provider,
  • Plan showing significant onsite habitat to be retained, created and enhanced post-development.

Applicants can provide a draft of the Biodiversity Gain Plan at validation stage or during determination, but this will need to be updated and submitted as a final version in accordance with the General Biodiversity Gain Condition post-permission being granted.

During Determination Process 

Should offsite habitat be required, and/or significant onsite habitat need to be secured through a S106 planning obligation, this will need to be completed and signed prior to the permission being issued.

Drafting of the Heads of Terms for the S106 and its agreement with the LPA is encouraged at the earliest opportunity.

A draft Habitat Management and Monitoring Plan (HMMP) must be provided, or otherwise information on proposed habitat management and monitoring provided, in sufficient detail to give Nottingham City Council’s LPA confidence that the habitat types being proposed are suitable for site conditions and the type of development proposed, creation and management is feasible and target conditions are achievable and can be delivered in the timeframe and with the finances and resources available, and that this can be secured for 30 years. Frequency and methods for monitoring effectiveness of habitat creation and establishment and management actions should also be included. This applies to significant onsite habitat and offsite habitat secured through S106 planning obligations.

The HMMP should also be capable of being adapted to be responsive to the outcome of ongoing monitoring to ensure that it is appropriate and effective to deliver the habitat types and conditions required to achieve net gain. 

Further information and a template for a HMMP can be found on the Creating a habitat management and monitoring plan for biodiversity net gain webpage.

The Local Nature Recovery Strategy (LNRS) for Nottinghamshire and Nottingham is currently in production and details of the ongoing process, collaborations, consultations and the outcomes for this are provided on Nottinghamshire County Council LNRS web page.

Spatial multipliers are used to influence metric calculations to take account of whether pre- and post-development habitats are located in ecologically significant areas, and termed ‘Strategic Significance’. Prior to the production and adoption of the LNRS, the following are considered to be of:

‘High’ strategic significance in Nottingham City are Sites of Special Scientific Interest, Local Nature Reserves, Local Wildlife Sites, Open Space Network (as defined in the Local Plan), and Ecological Networks (as defined in Greater Nottingham Blue-Green Infrastructure Strategy January 2022 (BGI Strategy (

‘Medium’ strategic significance is applied to other areas outside these designations that functionally connects to or links these high significance areas. 

‘Low’ strategic significance should be applied elsewhere. 

Where habitats cross boundaries between areas of different strategic significance, the habitat parcel should be split.

Biodiversity Net Gain requirements do not replace existing protections and considerations afforded to protected and notable species and designated sites. It does not reduce or replace the need to apply the mitigation hierarchy to the overall development and its impacts (as set out in paragraph 186 of the NPPF; National Planning Policy Framework - 15. Conserving and enhancing the natural environment)

BNG does not replace other enhancement measures required locally and set out in the Biodiversity SPD such as hedgehog-friendly fencing, bat and bird boxes etc. 

The Biodiversity Gain Hierarchy is additional to and distinct from the mitigation hierarchy and is set out in Article 37A of The Biodiversity Gain (Town and Country Planning) (Modifications and Amendments) (England) Regulations 2024.

The Biodiversity Gain Hierarchy means the following actions in the following order of priority:

For habitats with a distinctiveness score, applied in the metric, equal to or higher than four (i.e. those of medium distinctiveness or greater) - 

  1. Avoiding adverse effects of the development, or,
  2. Insofar as those adverse effects cannot be avoided, mitigating those effects.

For any habitats adversely affected by the development (i.e. those of any distinctiveness score), compensating for that adverse effect by - 

  1. Habitat enhancement of onsite habitat;
  2. Insofar as there cannot be that enhancement, creation of onsite habitat;
  3. Insofar as there cannot be that creation, the availability of registered offsite biodiversity gain for allocation to the development;
  4. Insofar as registered offsite biodiversity gain cannot be allocated to the development, the purchase of biodiversity credits. 

This therefore implies that the mitigation hierarchy must be applied to habitats with a distinctiveness score in the metric of 4 or more, but the priority for on-site measures first, followed by offsite and using statutory credits as a last resort applies to all habitats. 

In line with the above hierarchies, where habitats are to be created or retained and enhanced to offset losses associated with development, onsite habitat enhancement and creation is, in most instances, a priority over offsite compensation, as this means that the compensation is in as close proximity to the impact as possible.

However, where onsite creation is not possible, or is not ecologically advantageous, for example as it will create very isolated pockets of habitat, or those that are too small to be ecologically viable, then offsite may be the appropriate solution. Offsite is anything located outside the planning (red line) boundary.

A diagram showing how the mitigation hierarchy and biodiversity gain hierarchy work together is provided below:

mitigation hierarchy and biodiversity gain hierarchy flow

Multipliers inherent in the metric influence calculations when offsite habitat enhancement/creation is required, to take account of spatial risks and incentivise compensation as close to the location of impact as possible. For instance, offsite compensation that is located within the same LPA boundary or National Character Area (NCA) (National Character Area profiles) has a multiplier of 1 (therefore suffers no penalty), whereas offsite compensation that is outside the relevant LPA or NCA, but within a neighbouring LPA or NCA, has a multiplier of 0.75 (reducing the number of biodiversity units by 25%), and compensation outside the relevant or neighbouring LPA or NCA, has a multiplier of 0.5 (therefore effectively halving the number of biodiversity units being delivered). 

Nottingham City Council’s LPA area extends across a total of 5 different NCAs, and therefore the metric multipliers make no distinction between onsite or offsite compensation within the LPA boundary itself, or an offsite location as far away as Gainsborough, for example, in the far north of Nottinghamshire (also within Trent and Belvoir Vales NCA), or, as another example, as far south-west as Marston near Sutton Coldfield in Warwickshire (also within Trent Valley Washlands).The metric multipliers therefore do not, on their own, incentivise or penalise location of offsite compensation sufficiently to avoid biodiversity loss from the City or immediate surrounds.

Therefore, in a local context, when considering offsite compensation, preference is for delivery within the LPA boundary, secondly within a neighbouring LPA and only where these are clearly evidenced as not being possible, will a wider geographic spread be acceptable, including within the same or a neighbouring NCA to the development site. 

Under mandatory BNG, offsite habitats as well as significant onsite habitats created or enhanced to deliver BNG must be secured to be managed for at least 30 years using S106 planning obligations and/or other legal agreements (conservation covenants).

The definition of significant onsite habitat has been published, please refer to the Make on-site biodiversity gains as a developer webpage, which has been summarised as follows:

Significant enhancements are areas of habitat enhancement which contribute significantly to the proposed development’s biodiversity net gain relative to the biodiversity value before development.

Retention of existing habitat does not count as an on-site enhancement.

What counts as a significant enhancement will vary depending on the scale of development and existing habitat, but these would normally be:

  • Habitats of medium or higher distinctiveness in the biodiversity metric
  • Habitats of low distinctiveness which create a large number of biodiversity units relative to the biodiversity value of the site before development
  • Habitat creation or enhancement where distinctiveness is increased relative to the distinctiveness of the habitat before development
  • Areas of habitat creation or enhancement which are significant in area relative to the size of the development
  • Enhancements to habitat condition, for example from poor or moderate to good

Nottingham City Council does not anticipate making any further definition of significant onsite habitat at this time and will be guided by the above criteria on a case-by-case basis.

At this time Nottingham City Council is not registered as a Responsible Body and is not aware of any other Responsible Bodies locally for securing offsite habitats for BNG. Therefore, should it not be possible or only partially possible to deliver 10% BNG onsite and offsite habitats are required (and/or significant onsite habitats), this will need to be secured through a S106 planning obligation, or a Conservation Covenant with a Responsible Body identified by the applicant requiring the offsite gains.

The legal agreement securing appropriate management of habitats must last at least 30 years from finishing the habitat improvement. If securing:

  • On-site gains, the legal agreement starts from the date the development is completed
  • Off-site gains, the legal agreement starts from the date the habitat enhancement is finished

The length of time it will take to create or enhance the habitat (for example, one year) must also be included, as this will inform an accurate end date for the legal agreement.

Nottingham City Council’s LPA will work with applicants to clearly establish the defined point of development completion for when the period of at least 30 years begins, which will include completion of onsite habitat enhancement and not just completion of built structures, or issue of a buildings regulations notice.

This requirement is set out in PPG Paragraph 022 Reference ID: 74-022-20240214 Biodiversity net gain - Guidance - GOV.UK (

To ensure that habitats establish, thrive and meet target condition within the timeframe provided in the final metric calculations, it will be essential for habitats to be monitored so that management prescriptions can be responsive and adaptive. It is mandatory for the outcomes of this monitoring to be reported to the LPA (in the case of habitats secured through planning conditions or obligations), or the Responsible Body (in the case of habitats secured through Conservation Covenants) so that these bodies can undertake subsequent mandatory reporting to central Government on delivery of BNG and local outcomes.

The frequency of monitoring and reporting is to be agreed on a case-by-case basis, but is suggested that it should cover years 2, 5, 10, 15, 20 and 30 years since the habitat creation or enhancement was completed. However, should monitoring reports be proposed to be provided more or less frequently than this, ecologically sound justification should be provided.

Under mandatory BNG, all habitats must be managed for 30 years starting from the completion of development (as defined and agreed between the LPA and the applicant, see above).

Should habitat (and therefore Biodiversity Unit) delivery not be progressing as agreed via the approved Biodiversity Gain Plan, the LPA (or Responsible Body for habitats secured through Conservation Covenants) will have powers of enforcement. 

For more information on Habitat Management and Monitoring Plans see section on Planning Submission Requirements above.

List of acronyms

  • BGP – Biodiversity Gain Plan
  • BNG – Biodiversity Net Gain
  • DLUHC – Department for Levelling-Up, Housing and Communities
  • HMMP – Habitat Management and Monitoring Plan
  • LNRS – Local Nature Recovery Strategy
  • LPA – Local Planning Authority
  • NCA – National Character Area
  • NPPF – National Planning Policy Framework
  • PPG – Planning Practice Guidance
  • SPD – Supplementary Planning Document
  • S106 – Section 106 of the Town and Country Planning Act 1990
  • S73 – Section 73 of the Town and Country Planning Act 1990


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