Strategic significance in the statutory biodiversity metric

Strategic significance is the multiplier in the statutory biodiversity metric that reflects whether a habitat sits somewhere identified as ecologically important in a local strategy or plan. It applies to baseline habitat units and to post-intervention units, and it has three categories with different multipliers, the highest applying where the location is formally identified in a local strategy. It is not the same as the spatial risk multiplier used for off-site units, and conflating the two is the fastest way to a metric that fails review.

Reviewers see the same mistake repeatedly. An assessor ticks the high category because the site is near something green, with nothing in the file to support it. The multiplier flows through every habitat parcel, so one unsupported judgement changes the whole result.

What the multiplier measures

The metric asks, for each habitat parcel, whether its location is identified as strategically important for nature. The answer is a category, and the category carries a numerical multiplier applied to the units for that parcel.

The three categories work like this.

• High, where the location is formally identified in a local strategy or plan as important for that habitat or for nature recovery generally.
• Medium, where the location is ecologically desirable but not formally identified in such a document.
• Low, where neither applies.

The high category carries the largest uplift, medium a smaller one, and low leaves the units unchanged. Check the multiplier values in the version of the metric you are using, because the tool has been revised and the user guide is the authority on the current figures.

The category is assigned per parcel, not per site. A site can carry parcels in different categories where, for example, a watercourse corridor is identified in a strategy and the rest of the field is not.

Where the designation comes from

The source has to be a document, and the document has to say something about that location.

Local Nature Recovery Strategies, introduced by the Environment Act 2021 and prepared by responsible authorities across England, are the intended long term source. Where a strategy has been published for the area, its areas of particular importance for biodiversity and its priorities are the first place to look.

Where no strategy covers the site yet, the metric's user guide points to other documents that serve the purpose. In practice assessors draw on:

• Adopted local plan policies and proposals map designations for green infrastructure or biodiversity.
• Biodiversity opportunity areas and nature recovery network mapping produced at county or partnership level.
• Local wildlife site designations and their citations.
• Catchment or landscape scale strategies published by a public body.

Name the document, its publication date and the specific designation in the assessment. "The site lies within a biodiversity opportunity area" means nothing without the mapping reference.

The distinction from spatial risk

These two multipliers are frequently confused, and they do different jobs.

An off-site unit can therefore be affected by both: reduced for being in a neighbouring area, and uplifted for sitting in a location identified in a strategy. Getting one right does not excuse getting the other wrong.

Effects on off-site unit choices

Where a scheme cannot deliver its gain on site, strategic significance shapes which off-site option is worth buying. A habitat bank inside an area identified in the local nature recovery strategy generates more units per hectare than an identical habitat outside it, which changes the price per unit you should be willing to pay.

It also changes the planning argument. A local planning authority reading a biodiversity gain plan is more comfortable with off-site delivery that aligns with its own strategy than with units bought wherever they cost least, and the strategic significance category is the visible expression of that alignment.

Two practical notes. Ask the habitat bank for its strategic significance evidence rather than accepting the category on its brochure. And check the date of the strategy relied on, because a strategy published after the metric was run can change the answer.

Evidencing the category you claim

Build a short evidence appendix for the metric. For each parcel, record:

1. The category claimed.
2. The document relied on, with its title, author and date.
3. The specific policy, map or designation within that document.
4. A plan showing the parcel against the designation boundary.
5. A note where the judgement is finely balanced, explaining why the category was chosen.

That appendix is what a reviewer asks for first. Its absence is what turns a straightforward review into three rounds of correspondence, and the same discipline applies to any contested classification, much as it does when arguing about best and most versatile agricultural land.

Common errors in assignment

The high category claimed on the basis of proximity to a designated site rather than on the site's own identification in a strategy. Being 200 metres from a local wildlife site does not make a field strategically significant.

Using a strategy that covers a different administrative area, which happens where a site sits near a boundary.

Applying a single category across the whole site for convenience, when the designation covers only part of it.

Assigning the category to the habitat type rather than to the location. The question is about where the parcel is, not about how good the habitat is; distinctiveness and condition are separate inputs and they already do that work.

Carrying the baseline category into the post-intervention sheet without rechecking it. The location does not change, but the habitat proposed there might sit outside what the strategy identifies.

And relying on a draft strategy that has not been published. A consultation draft is not a published strategy, and an authority may say so.

Where this sits in the wider gain plan

The statutory metric must be completed by a competent person, and the biodiversity gain plan has to be approved by the local planning authority before development begins under the Environment Act 2021 regime. Strategic significance is one input among several, and it will not rescue a metric with the wrong habitat classification or an optimistic condition assessment.

Treat it as a documentation exercise rather than a judgement call. Where the document exists, cite it. Where it does not, claim medium or low and say why. An assessment that claims high everywhere reads as advocacy and invites the reviewer to check everything else too.

A draft can set out the method and the questions the metric asks, using the report types as a structure, but the calculation and the professional judgement belong to the competent person who signs it. Comparable arguments about classification come up in openness of the Green Belt cases too. To scope the wider document set for a site, enter your postcode on PlanScope.

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