When a council must carry out an appropriate assessment

An appropriate assessment planning application duty falls on the council, not the applicant. Under regulation 63 of the Conservation of Habitats and Species Regulations 2017, a competent authority must carry out an appropriate assessment before granting permission for anything likely to have a material effect on a habitats site, either alone or in combination with other plans and projects. The applicant's ecology work feeds that assessment. It cannot be the assessment.

Getting this wrong produces permissions that are vulnerable to challenge, and it is one of the few areas of development control where a procedural slip is fatal rather than curable.

The screening stage and the test it applies

Screening asks one question: is the proposal likely to have a significant effect on a habitats site, alone or in combination with other plans or projects, and is it not directly connected with the management of that site. The threshold is low. It is a likelihood test applied on a precautionary basis, and the Court of Justice made clear in Waddenzee in 2004 that the trigger is the possibility of an effect rather than proof of one.

Three consequences for practice. Distance is relevant but not decisive, because hydrological and air quality pathways reach a long way. The absence of a recorded qualifying feature on the application site proves nothing, since effects on the site's features can arise from off-site sources. And a conclusion of no likely effect has to be reasoned on the evidence rather than asserted in a single line of an officer report.

The screening output should name the habitats site, list its qualifying features, identify each impact pathway considered, and explain why each is ruled out. Where survey evidence is thin because access was refused, that limitation belongs in the screening record, and our note on ecology surveys where access to adjoining land is refused covers how to document it.

Mitigation cannot rescue the screening stage

This is the rule most often broken. In People Over Wind and Sweetman in 2018 the Court of Justice held that measures intended to avoid or reduce harmful effects cannot be taken into account at the screening stage. Screening asks whether an effect is likely in the absence of mitigation.

The practical effect is that a scheme with embedded ecological mitigation designed specifically to protect a habitats site will generally screen in, and the mitigation is then assessed at the appropriate assessment stage where it belongs. Councils that continue to screen out on the strength of mitigation are creating grounds of challenge.

Two distinctions worth holding onto. Measures that form part of the scheme for reasons unconnected with the habitats site, such as a drainage design required by the lead local flood authority, are part of the project description rather than mitigation. And avoidance through design, such as siting development outside a functionally linked area entirely, can be part of the project rather than a measure bolted on to address an effect. The line is difficult to draw, and where it is arguable the safer course is to screen in.

In-combination effects and how they are handled

The in-combination test is what catches schemes that would be harmless on their own. It requires the authority to consider the proposal alongside other plans and projects, which in practice means extant permissions not yet implemented, allocations in the development plan, and applications under consideration.

Air quality on protected heathland is the familiar example. Traffic from one small scheme adds little to nitrogen deposition on a site already at or above its critical load, and the cumulative effect of many such schemes is the problem. The High Court's decision in Wealden District Council v Secretary of State for Communities and Local Government in 2017 turned on exactly that failure to assess in combination.

Nutrient loading in affected catchments works the same way, through wastewater and surface water pathways rather than air.

Where a strategic solution exists, such as a mitigation strategy funded by tariff contributions, the authority can rely on it, provided the strategy itself has been assessed and the contribution is secured.

The competent authority, and Natural England's role

The council is the competent authority for a planning application. It must consult Natural England as the appropriate nature conservation body and have regard to its representations, and where Natural England objects the authority has to grapple with that objection rather than note it.

Natural England's advice is not binding. An authority can depart from it, but doing so requires the authority to have its own evidence base, since the assessment has to be capable of removing reasonable scientific doubt about adverse effects on site integrity. In practice councils rarely disagree with a clear objection, and applicants are better served by resolving the objection than by inviting the authority to overrule it.

Applicants routinely prepare a shadow habitats regulations assessment for the authority to adopt. That is normal and helpful, provided it is written as a document the authority can own, with the reasoning exposed rather than the conclusion asserted. A Preliminary Ecological Appraisal and any Protected Species Survey work sit underneath it as evidence. Protected species surveys and any licence application require a suitably licensed ecologist under the Wildlife and Countryside Act 1981 and the 2017 Regulations, and a draft report is a starting point for that professional rather than a substitute.

The assessment itself, and the standard it must reach

The appropriate assessment has to enable the authority to conclude, beyond reasonable scientific doubt, that the proposal will not adversely affect the integrity of the habitats site, taking mitigation into account.

That is a demanding standard and it shapes what the document must contain:

1. The site's conservation objectives, taken from the published objectives rather than paraphrased.
2. Each pathway carried forward from screening, assessed against those objectives.
3. The mitigation relied on, described precisely enough to be secured by condition or obligation.
4. The mechanism securing it, named.
5. Monitoring where the effectiveness of mitigation is uncertain, with a remedy if it underperforms.
6. A reasoned conclusion on integrity, addressing residual uncertainty openly.

Uncertainty is the hard part. Where the evidence leaves genuine doubt, the correct conclusion is that an adverse effect cannot be ruled out, which moves the application into the derogation route rather than allowing a finely balanced approval.

Derogation: alternatives and overriding public interest

Where an adverse effect on integrity cannot be excluded, regulation 64 allows permission only if there are no alternative solutions and there are imperative reasons of overriding public interest. Compensatory measures must then be secured to maintain the coherence of the network of habitats sites.

This route is rare in development management and demanding in practice. The alternatives test looks at alternatives to the project in its location and form, not merely at design variants. The public interest test is judged against the interest served by the site's protection, and for sites hosting priority habitats or species the categories of interest that can qualify are narrower still.

Most applicants reach this point because the scheme was designed before the habitats position was understood. The better sequence is to screen early, then design.

Recording the assessment in the decision

The assessment must be evidenced on the file before permission is granted, not reconstructed afterwards. That means the officer report or a separate assessment document setting out the screening reasoning, the appropriate assessment where one was required, Natural England's advice and the authority's response to it, and the conditions or obligations securing mitigation.

Where a committee resolves to grant against the officer recommendation, the assessment has to be revisited before the decision notice issues. And where circumstances change between resolution and issue, such as new deposition evidence or a revised catchment position, the authority has to look again. Browse the ecology and environmental report types to see which supporting documents a site with a habitats constraint is likely to need.

PlanScope drafts ecological and planning documents structured to UK planning policy, with missing site facts flagged. Reports should be reviewed before submission, and we do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.