Refused for missing biodiversity net gain information
Most refusals that mention biodiversity net gain are information failures rather than habitat failures, and those are usually cured faster by resubmitting than by appealing.
A biodiversity net gain refusal appeal is usually the wrong first instinct. Most refusals that mention biodiversity net gain are not refusals on the merits of the habitat position. They are refusals because the application did not carry the information the authority needed to be satisfied the gain condition could be met, and an information gap nearly always costs less to close by resubmitting than by appealing. Work out which kind of refusal you have before you do anything else.
Why an information failure is different from a policy failure
Read the reason for refusal against the officer report. There are three patterns and they call for different responses.
The first is a validation or information failure: no metric calculation, no statement about whether the gain condition applies, a baseline taken at the wrong date, or a completed metric that does not match the submitted layout. Fix and resubmit.
The second is a substantive habitat problem: the site contains irreplaceable habitat, or the scheme cannot achieve the required gain on site and no off-site route has been evidenced. That is a design and delivery problem, and appealing without solving it achieves nothing.
The third is a dispute about whether the regime applies at all, usually over an exemption. That one can be worth appealing, because it turns on the interpretation of the regulations rather than on planning judgement.
The gain condition and what has to be with the application
Schedule 7A to the Town and Country Planning Act 1990, inserted by the Environment Act 2021, deems every relevant planning permission in England to be subject to a condition that development may not begin until a biodiversity gain plan has been submitted to and approved by the authority. The regime applies to major development from 12 February 2024 and to small sites from 2 April 2024.
The gain plan itself comes after permission. What has to be with the application is a separate list, set out in the amended application requirements: a statement of whether the applicant believes the condition applies, the pre-development biodiversity value of the on-site habitat, the date used for that assessment, the completed statutory metric, and a statement about any irreplaceable habitat.
Applicants who assume that "the gain plan is post-permission" means "nothing is needed now" are the ones who get refused. The authority cannot form a view on deliverability without the metric, and several authorities will refuse rather than validate an application that lacks it.
Exemptions and how disputes about them arise
Three exemptions come up on small schemes.
Householder applications are exempt. So is de minimis development, meaning development that does not affect a priority habitat and affects less than 25 m² of on-site habitat or less than 5 metres of on-site linear habitat. So is self-build and custom build development consisting exclusively of no more than nine dwellings on a site of no more than 0.5 hectares, where the dwellings are built by or commissioned by the people who will live in them.
Disputes cluster around two of those. On de minimis, the argument is usually about whether an area of modified grassland or a hedgerow has been affected at all, and it is settled by a habitat plan showing exactly what is disturbed, including construction access and material storage. On self-build, the argument is about whether the development is exclusively self-build dwellings and whether the evidence of that is adequate.
If you think you are exempt, say so explicitly in the application and evidence it. Silence reads as an omission.
Baseline habitat disputes and survey timing
The pre-development value is normally taken on the date of the application, or an earlier date agreed in writing with the authority. That creates two traps.
The first is degradation. Where habitat has been cleared, mown, sprayed or otherwise reduced without permission after the relevant date in January 2020, the authority can assess the baseline as it was immediately before those activities. So a farmer who ploughed a species-rich margin, or an owner who cleared scrub to tidy the site before selling, leaves a baseline that no longer exists on the ground and still has to be compensated.
The second is survey season. Habitat condition assessment under the statutory metric needs the vegetation to be identifiable, which broadly means the growing season, roughly April to September, with the middle of that window best for grassland. A winter survey of a grassland site will either be downgraded or challenged.
A Preliminary Ecological Appraisal by a suitably qualified ecologist is the sensible first step, and councils expect a qualified author. The statutory metric itself must be completed by a competent person under the Environment Act 2021 regime, and a Biodiversity Net Gain Assessment drafted with AI assistance is a starting point for that person rather than a substitute for their judgement.
Submitting the metric at appeal stage
You can put a metric in with an appeal, and inspectors will look at it. Whether that helps depends on how much the scheme changes as a result.
Two constraints apply. An inspector will not accept amendments that alter the development so much that the authority and consultees have not had a fair chance to comment, which is the Wheatcroft principle in everyday practice. And an appeal decided on written representations gives you no opportunity to negotiate, so a metric that raises new questions will simply be weighed as it stands.
There is also a costs risk running the other way. Where an authority refused for missing information that was available and could have been supplied, an award of costs against it is at least arguable. Where the applicant supplies at appeal what should have been supplied with the application, the authority may seek costs instead.
Off-site units and credits as a fallback
Where the gain cannot be achieved on site, the hierarchy runs on-site first, then off-site units, then statutory biodiversity credits sold by government as a last resort and priced to be unattractive.
Off-site units have to be registered on the biodiversity gain sites register and legally secured, usually by a conservation covenant or a section 106 agreement, with a 30-year management obligation. That takes time and it takes a willing landowner or habitat bank in a suitable location, because the metric applies spatial risk multipliers that reduce the value of units delivered further away.
Start those conversations before the appeal, not after. And where the shortfall is being covered by an obligation the council will not accept, the position is similar to the one described in the notes on unilateral undertakings when a section 106 is refused.
Getting the position agreed with the ecologist first
Before choosing a route, get three things in writing from your ecologist: the baseline calculation with the survey date and condition assessment, the post-development calculation for the scheme as refused, and a short note on what change to the layout would close any shortfall.
If the shortfall closes with a wider buffer, a different boundary treatment or a smaller area of hard surfacing, resubmit. The comparison between the two routes is set out in the notes on choosing between a free go resubmission and an appeal, and for an information-based refusal the resubmission almost always wins on time and cost.
Appeal when the authority is wrong about whether the regime applies, wrong about the baseline, or refusing to accept an off-site solution that is properly secured. Those are arguments an inspector can decide. A missing spreadsheet is not.
Enter your postcode on PlanScope to see which reports your site is likely to need before you resubmit. This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.
Frequently asked questions
Does the biodiversity gain plan have to be submitted with the application?
No, the gain plan itself is approved after permission and before development begins. What must accompany the application is a statement of whether the condition applies, the pre-development biodiversity value, the date used, the completed statutory metric and a statement about irreplaceable habitat. Assuming nothing is needed at application stage is the usual cause of refusal.
Which small schemes are exempt from biodiversity net gain?
Householder applications are exempt. So is de minimis development that does not affect a priority habitat and affects less than 25 square metres of on-site habitat or less than 5 metres of linear habitat. So is self-build and custom build development of no more than nine dwellings on a site of no more than 0.5 hectares.
What happens if habitat was cleared before the application?
The degradation rules allow the authority to assess the pre-development value as it was immediately before unauthorised activities carried out after the relevant date in January 2020. The baseline then reflects habitat that is no longer on the ground, and it still has to be compensated. Never clear or spray a site before the ecologist has recorded it.
Can I submit the metric for the first time at appeal?
You can, and an inspector will consider it. The limit is that amendments which change the scheme so much that the council and consultees have not had a fair chance to comment will not be accepted. On written representations there is no opportunity to negotiate, so a metric that raises fresh questions is simply weighed as it stands.
When are off-site units or statutory credits the answer?
Only after on-site gain has been maximised. Off-site units must be registered on the biodiversity gain sites register and legally secured for 30 years, and the metric applies spatial risk multipliers that reduce the value of units delivered further from the site. Statutory credits are a last resort and are priced to be unattractive.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.