- A Biodiversity Gain Plan is required to be submitted to discharge the statutory biodiversity gain condition (part 2, Schedule 7 of the Town and Country Planning Act 1990).
- This is a pre-commencement condition that is contained within the legislation and is deemed to apply to all planning permission subject to statutory Biodiversity Net Gain.
- The statutory biodiversity gain condition is not reproduced on the decision notice, but an informative is instead used as a reminder for applicants.
- An application to discharge the biodiversity gain condition is made through the usual channels, please indicate as part of the submission that you intend to discharge the statutory Biodiversity Gain Condition.
- The biodiversity gain condition discharge is then separated into an application with the CONBGP suffix for recording purposes.
Biodiversity Net Gain (BNG)
Biodiversity Net Gain is an approach to development that leaves biodiversity in a measurably better state after development than before, after first avoiding and minimising harm.
From 12 February 2024 all major developments in England have to deliver 10% BNG and from 2 April 2024 all developments (except for some exceptions, such as householder applications) will have to deliver 10% BNG. This requirement does not replace, but is in addition to, the existing policy and legal requirements related to biodiversity and development.
Applicants must remember that their planning permission will contain a statutory deemed planning condition for a Biodiversity Gain Plan to be submitted to the local planning authority for approval before development commences if statutory BNG is applicable. This condition is “deemed” because it is contained within Schedule 7A of the Town and Country Planning Act. It therefore doesn’t appear in the list of conditions on your decision notice and could get missed.
Applications to discharge a Biodiversity Gain Plan will be separated out from other condition discharge applications using the “CONBGP” suffix. This does not mean that applicants will be charged again, but it does allow the local authority to track these applications for reporting purposes.
New exemptions (from 6 August 2026)
- Developments of 0.2 hectares or below (where the site area within red line boundary is 0.2ha or below)
- Developments subject to the ‘de minimis’ rule (where impact is less than 25 square metres (5m by 5m) of on-site habitat within the red line boundary and/or 5 metres of on-site linear habitats such as hedgerows)
- Temporary developments (short-term development where the whole development is temporary and planning permission is granted for 5 years or less)
- Baseline habitat information may still be required to inform these applications where the temporary permission is likely to be extended or made permanent in the longer term
However, these exemptions do not apply where there would be an impact on priority habitat on-site. A development ‘impacts’ a habitat if it decreases its biodiversity value.
Self-build and custom build applications made on or after 6 August 2026 are no longer exempt.
To measure BNG and assess the impacts of planning applications Defra’s Biodiversity Metric (or for smaller sites the small sites metric) should be used.
Biodiversity Net Gain: Good practice principles for development (published by CIEEM) should be followed when designing developments and preparing planning applications. Further advice can be obtained from the council via our pre-application advice service.
Planning applicants will need to provide information on the biodiversity value of their application site and how they plan to deliver 10% BNG as part of their application. Details can be found on our validation webpages.
In most cases, BNG should be provided on the development site, i.e. within the red line boundary, but in some cases, and in agreement with the council, it may be necessary to provide the net gain off-site. This could be on land within the planning applicant’s control (e.g. land within the blue line boundary via legal agreement) or through the purchase of the required biodiversity units (quantity and type) from a habitat bank. Details of local habitat banks can be found on the Oxfordshire Local Nature Partnership website: https://www.olnp.org.uk/biodiversity-net-gain-bng-sites-in-oxfordshire Those listed here have been certified with the Oxfordshire NatureMark by demonstrating a commitment to delivering genuine, high quality outcomes for biodiversity.
From 6 August 2026, small (‘minor’) developments that are not already exempt can consider onsite and offsite gain at the same time. They can choose to deliver off-site without considering on-site first.
Further guidance is available:
Government guidance on the BNG process is available at: Developer guidance.
Strategic Significance
For the strategic significance multiplier in the biodiversity metric, the Oxfordshire Local Nature Recovery Strategy (LNRS) published by Oxfordshire County Council on 12th November 2025 must be used in line with the metric user guides available here.
If you have planning permission (including from before 12 November 2025) and still need to discharge the pre-commencement statutory planning condition for the submission of a Biodiversity Gain Plan, then you will need to update your biodiversity metric to refer to the published LNRS, the map for which is available here. Please speak to your project ecologist for further advice.
On-Site Significant Enhancement
To identify onsite significant enhancements, we are using the Verna Mycelia software in combination with the national guidance published by Defra which can be found here: https://www.gov.uk/guidance/make-on-site-biodiversity-gains-as-a-developer#significant-on-site-enhancements
This states:
“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
Non-significant enhancements are habitat enhancements whose loss will not significantly decrease the development’s biodiversity value. They should still be included in your metric calculations. Examples could include private gardens which have a low distinctiveness value, or container planting. These enhancements do not normally require maintenance provisions, so for non-significant enhancements, you do not need to have an HMMP, legal agreement or commitment to maintain them for 30 years.”
Private gardens, ornamental planting, and small areas of amenity grassland are unlikely to be considered ‘significant’. Local planning authorities are not obliged to secure the long-term management of these features for the purpose of mandatory BNG, but these areas (excluding private gardens) will likely still have long-term management secured through other mechanisms.
BNG frequently asked questions
- Use the government Biodiversity Gain Plan template, complete all relevant sections, sign and date (https://www.gov.uk/government/publications/biodiversity-gain-plan)
- In all cases this must be submitted with:
- Statutory biodiversity metric calculations (full or small sites metric)
- Baseline habitat plan
- Post-development habitat plan or landscape plan
- Where the full statutory biodiversity metric has been completed the following will also be required:
- Condition assessments
- Baseline Biodiversity Net Gain report
- Where the biodiversity net gain comprises onsite significant enhancement a Habitat Management and Monitoring Plan will also be required.
- Where off-site units have been purchased the following requirements must be met but this is usually done by the off-site provider:
- Completion of the off-site section of the biodiversity metric
- Allocation of the off-site units to your planning permission on the Natural England National Biodiversity Gain Sites Register
- Onsite refers to all land within the site boundary of the application (redline boundary).
- The redline boundary used for the biodiversity net gain assessment must be the same as the redline boundary of the planning application and all onsite area, hedgerow and watercourse habitats must be recorded in the BNG assessment.
- Where the redline boundary crosses into the riparian zone of off-site watercourses, the associated length of watercourse must be included in the onsite BNG watercourse assessment.
- Generally, proposals should be designed as part of the wider green infrastructure and landscaping strategy.
- Habitat types and condition targets should be realistic and achievable within the context of the site including, soil type, flood risk, protected and priority species, management etc.
- The proposals should contribute towards the actions in the Oxfordshire Local Nature Recovery Strategy, referred to as ‘potential measures’ (https://www.oxfordshire.gov.uk/residents/environment-and-planning/local-nature-recovery-strategy-lnrs)
- The overall aim is to contribute towards local nature recovery and the Lawton Principles of more, bigger, better and joined up (https://www.gov.uk/government/news/making-space-for-nature-a-review-of-englands-wildlife-sites-published-today).
- The creation and enhancement of individual habitats (including individual trees and hedgerows) in private gardens cannot be legally secured and therefore cannot count towards meeting the statutory 10% BNG requirement.
- Areas of habitat created in private gardens must be recorded as ‘vegetated garden’ post-development.
- If habitats are being retained within a private garden they can only be recorded as retained in the biodiversity metric calculations (i.e. cannot be enhanced).
- It is possible to create green roof habitat on private dwellings, and this must be recorded as ‘other green roof’ for the purpose of the biodiversity metric calculations.
- We would encourage other biodiversity enhancements within gardens to be incorporated where possible such as flowering lawns, native hedgerows, native or fruit trees, and other species with known benefits to wildlife (e.g., lavender, honeysuckle, evening primrose) as a contribution towards local nature recovery which would also meet Local Plan Policy EH3.
- To meet the 10% BNG objective off-site, units can be purchased from an established off-site provider.
- When off-site units are purchased, the habitat creation, management and monitoring would be the responsibility of the off-site provider.
- If you are planning to purchase off-site units, complete the relevant section of the BNG Statement submitted as part of the application. Off-site units do not need to be purchased to receive planning consent.
- Details of off-site units are then confirmed as part of the Biodiversity Gain Plan at discharge of condition stage. Any off-site units must be allocated to the specific planning permission on the National Biodiversity Gain Sites Register in order to successfully discharge the biodiversity gain condition.
- Off-site habitat proposals must be secured for at least 30 years by legal agreement in order to comply with the statutory biodiversity net gain process (this can be a S106 with the LPA or a conservation covenant with a responsible body)
- The off-site area must also be registered with Natural England on the National Biodiversity Gain sites register (associated with £639 fee).
- A habitat management and monitoring plan must be prepared.
- Off-site habitats must be created or enhanced, managed and monitored (including surveys by a suitably qualified ecologist) for the 30 year period and where necessary any remedial measures implemented.
- Where the legal agreement is with the LPA, monitoring reports are submitted to the LPA at agreed intervals (usually years 1, 3, 5, 10, 15, 20, 25 and 30). The LPA would also recover costs associated with the monitoring process (https://www.westoxon.gov.uk/planning-and-building/wildlife-and-biodiversity/biodiversity-net-gain-bng/).
- Where off-site BNG within the applicant’s landholding is proposed as part of a planning application, the full details of the off-site BNG proposals must be submitted including a baseline habitat survey, condition assessment, habitat map, biodiversity metric and the proposed habitat creation and enhancements.
- Usually, the S106 would be completed as part of the planning permission.
- Trees removed for any reason must be included in the BNG baseline (unless justified by the biodiversity metric user guide [trees less than medium size in hedgerows, small trees in private gardens]) in accordance with the rules that apply to pre-development habitat degradation.
- There are special provisions for the calculation of the pre-development biodiversity value of onsite habitat when loss or impact to habitats (or ‘degradation’) has occurred prior to the submission of a planning application and Biodiversity Gain Plan in order to discourage the deliberate degradation of existing onsite habitats to reduce the pre-development biodiversity value.
- Where habitat degradations has occurred in advance of a planning application being submitted, the following must be provided:
-
- a statement setting out that these degradation activities have been carried out;
- confirmation of the date immediately before these activities were carried out;
- the pre-development biodiversity value of the site on this date;
- the completed metric calculation tool showing the calculations, and
- any available supporting evidence of this.
- Where there is insufficient evidence, a precautionary approach should be taken to assessing the habitat value.
- Paragraphs 6 and 6A of Schedule 7A of the Town and Country Planning Act 1990 include cut off dates to define when habitat degradation must be accounted for as follows:
- Unauthorised habitat degradation (i.e. not in accordance with a planning permission) carried out after 30th January 2020
- Where the activity implements or is in connection with a planning permission and was carried out after 25th August 2023, but that permitted development has not been completed
Monitoring the delivery of BNG
Where the proposed onsite gains are not significant, management and monitoring do not need to be secured for the statutory 30-year period. The delivery of these habitats would be secured via conditions relating to the implementation of the details, the landscaping scheme and a Landscape and Ecology Management Plan (LEMP) that would cover the period up to when the habitats are expected to reach their target condition with a final audit report to confirm successful implementation.
Where the proposed onsite gains are significant enhancements, the council will still include relevant planning conditions for the submission of landscaping details and a Habitat Management and Monitoring Plan (HMMP) for approval. However, the council may decide to secure the 30-years of management and monitoring by S106 agreement. This decision would depend on the type of development, the habitat type and distinctiveness, the difficulty rating of creating or enhancing the habitats, and who has responsibility for implementing the approved HMMP. A S106 agreement is considered to be important for residential developments where responsibility would pass from the developer to another management body.
Section 106 agreements can also used to secure the delivery of off-site BNG on land owned by the developer and on habitat banks.
The council can also recoup the costs associated with monitoring the delivery of BNG for the 30-year period via the S106 agreement. Planning Practice Guidance (PPG) states: “Local planning authorities can charge a monitoring fee though section 106 planning obligations, to cover the cost of monitoring and reporting on delivery of that section 106 agreement for both off-site and on-site BNG.”
Habitat Management and Monitoring Plan (HMMP)
The HMMP sets out the monitoring regime for each BNG site for the 30-year period in terms of how the habitats will be checked by the developer’s or the habitat bank owner’s ecological consultant(s), what remedial measures may need to be implemented and when monitoring reports will be submitted to the council.
A standard timeline is becoming widely used and monitoring events are generally expected to take place in years 1, 3, 5, 10, 15, 20, 25 and 30 following the completion of development (or completion of the habitat creation/enhancement works for habitat banks). WODC is also conditioning a final audit report that may be submitted in year 31 to confirm the success of the BNG delivery for the full statutory period. The actual timing of monitoring may differ depending on the development type, habitat types and any specific site constraints or considerations, e.g. soil type, flood risk, etc, and is usually confirmed as part of the HMMP.
Council Monitoring Responsibilities
When the monitoring reports are submitted to the council, it may be necessary for them to carry out their own monitoring to ensure that the BNG is being delivered effectively. This could include:
- Setting up an internal monitoring system;
- Ensuring that monitoring reports are received at the agreed times;
- Reviewing the reports for adequacy and quality;
- Reviewing the results of the report to ensure that the BNG outcomes are being delivered;
- Ground-truthing the reports from time to time through site visits;
- Communicating the council’s findings to the applicant, landowner or habitat bank operator, or other interested third parties;
- Taking enforcement action where reports are not received, are of insufficient quality, or show that the required BNG is not being delivered;
- Agreeing remedial actions that need to be taken and ensuring that these are carried out; and
- Reviewing and agreeing updated Habitat Management and Monitoring Plans.
Verna BNG Monitoring Fee Calculator
The Verna BNG Monitoring Fee Calculator was developed to assist local planning authorities (LPA) and is publicly available to download on their website https://verna.earth/news-item/free-tool-how-to-calculate-biodiversity-net-gain-monitoring-charges/
The calculator takes account of the cost to the LPA in both reporting and non-reporting years and translates costs in future years into the value of today’s money. The calculator assumes that the monitoring fee is received in a single upfront payment. Using this free resource ensures that the monitoring fee calculations are replicable and consistent, and can therefore be effectively reviewed by the council, e.g. on an annual basis, to take account of increasing costs.
In the calculators used by WODC, categorisation of the types of BNG monitoring are based on the size of the site [small (0 to 5ha), medium (5.1 to 20ha), large (20.1 to 40ha) and a bespoke approach to sites larger than 40 hectares (ha)] and the complexity of creating or enhancing habitats based on the highest technical difficulty rating in the Statutory Biodiversity Metric [low, moderate or high].
The monitoring frequency is set as a standard for all sites at years 1, 3, 5, 10, 15, 20, 25 and 30. This equates to at least 8 no. monitoring events within the 30-year period. This could be updated on a bespoke basis for individual developments depending on the specifics of the case.
Monitoring fees
Monitoring fees will be calculated on a bespoke basis for BNG sites of over 40ha or where phased delivery of BNG is likely to take place (there is a separate process in Planning Practice Guidance for phased developments https://www.gov.uk/guidance/biodiversity-net-gain#determination-of-the-planning-application – paragraphs 053 to 063). The bespoke approach would consider the size and complexity of the BNG proposal and other relevant factors. The Verna BNG monitoring fees calculator would be used to produce a bespoke figure on a case by case basis.
Monitoring fees would normally be paid as a one-off sum within 10 working days of the commencement of development or shortly after habitat banks or other offsite BNG sites have been formally added to the National Biodiversity Gain Site Register. The payment terms would be set as part of the associated S106 agreement.
There may be requests to spread payments over 18 – 24 months and these will be considered on a case-by-case basis.
The Trust for Oxfordshire’s Environment (TOE) advocates reasonable and equitable costs for all types of developer and landowner regarding both development sites and habitat banks, and WODC has therefore taken this into account when preparing the fee schedule below.
The fees will be reviewed annually as part of the Council’s overall review of fees. This review would include an analysis of salary, inflation rate and other known costs, and reference to other LPAs’ monitoring fees at that time to ensure that the fees generated by the Verna Calculator are comparable.
WODC’s BNG monitoring fees are provided in the table below.
| West Oxfordshire District Council's BNG Monitoring Fees 2025 - 26 | ||
|---|---|---|
| Size of site | Complexity | Associated Fee |
| Small (0-5 ha) | Low | £3,000 |
| Moderate | £4,000 | |
| High | £5,000 | |
| Medium (5+ to 20 ha) | Low | £6,250 |
| Moderate | £7,500 | |
| High | £8,500 | |
| Large (20+ to 40 ha) | Low | £10,250 |
| Moderate | £12,500 | |
| High | £14,500 | |
| 40+ ha | Bespoke approach will be needed | |
District Licence and Biodiversity Net Gain (BNG)
Users of the District Licence scheme can also benefit from the integrated Biodiversity Net Gain package managed by NatureSpace and the Newt Conservation Partnership. More information on this can be found on the NatureSpace website.