Reading a decision letter for reusable reasoning

Inspector decision letter reasoning is the most useful free material available to anyone preparing planning applications, and most practices waste it by reading only the final paragraph. The reusable part sits in the reasons section, where an inspector explains how a policy was interpreted, what evidence was accepted, what weight each consideration attracted and why. That reasoning travels. The outcome does not, because every appeal turns on its own facts and its own evidence.

So read decision letters for method rather than for results, and build a library organised by issue rather than by site.

How a decision letter is put together

The format is consistent enough that you can navigate it quickly.

The heading carries the appeal reference, the site address, the appellant, the local planning authority, the original application reference and the date of the decision. The reference itself is informative: it begins with APP, then a code for the authority, then a letter identifying the appeal type, then the case number. The appeal type letter tells you whether you are reading a full planning appeal, a householder appeal, an enforcement appeal, a lawful development certificate appeal or a listed building consent appeal, and the tests differ between them.

Then the decision paragraph, which states whether the appeal is allowed or dismissed and, if allowed, that permission is granted subject to the conditions in a schedule. Then procedural matters, which record anything unusual about how the appeal was handled, including amended plans, a site visit arrangement or a late document.

Then the main issues, the reasons, other matters, conditions and a conclusion, followed by the inspector's name and the schedule of conditions. Where an appeal was recovered or called in, you are reading an inspector's report with a separate decision letter from the Secretary of State, and the two can reach different conclusions.

Read the procedure too. A decision reached after an inquiry with expert evidence carries more analytical weight than a written representations decision on a householder extension, so say which one you are citing.

The main issues section and why it matters most

The inspector states the main issues in one or two sentences, and that statement is the single most useful line in the letter. It tells you what the inspector considered determinative out of everything both parties argued.

The pattern is instructive over a run of decisions. If four inspectors in the same policy area all frame the main issue as the effect on the character and appearance of the area rather than as compliance with a numerical standard, that tells you where to put your effort in an application. If the main issue is consistently framed as whether the proposal would be inappropriate development in the Green Belt and, if so, whether very special circumstances exist, then your statement should be structured that way too.

Note what the inspector excludes from the main issues. Matters raised by objectors and then dealt with briefly under other matters are being signalled as secondary, which is useful when you are deciding how much space to give an issue in a submission.

Our note on reading a refusal notice and turning it into a plan covers the equivalent exercise on the council's own reasons, and the two read well together.

Separating findings of fact from planning judgement

This is the distinction that determines what you can reuse.

Findings of fact are statements about the world: the separation distance between two elevations, the difference in ground level, what the inspector saw from a particular viewpoint, what a policy says, what the parties agreed. Where a fact applies to your site as well, it transfers. Where an inspector records that a council's design guide expresses a distance as guidance rather than a requirement, that reading of the document holds good the next time the same document is applied.

Planning judgement is the evaluative step: whether harm is acceptable, how much weight a benefit attracts, whether an effect is material. Judgement is exercised on the facts of that case and it does not transfer directly. What transfers is the reasoning structure, meaning the order in which the inspector took the questions and the factors treated as relevant to each.

So quote a factual finding as a finding. Quote a judgement as an illustration of approach. Confusing the two is the fastest way to have a citation dismissed by a case officer who has read the decision more carefully than you have.

Interpretation of policy sits between the two. It is a matter of law in some respects and judgement in others, and an inspector's reading of an ambiguous local policy is persuasive rather than authoritative.

The weight vocabulary and how to reuse it

Inspectors use a consistent vocabulary for weight, running from substantial through significant and moderate to limited and little. They also use standard formulations for the statutory tests, such as considerable importance and weight in heritage cases, or great weight in Green Belt and designated landscape cases.

Adopt that vocabulary in your own documents. A planning statement that says the benefit attracts moderate weight, and explains why, reads as professional. One that says the benefit is very important reads as advocacy.

Also pay attention to how inspectors express conclusions on harm. Phrases such as harm at the lower end of less than substantial, or limited harm to the character of the area which would not be significant, are calibrated deliberately. Using the same calibration in a submission makes the council's job easier and makes your position harder to caricature.

Where an inspector has criticised an approach, note the wording. Decisions in which an inspector observes that a standard was applied mechanically, or that a council produced no evidence for an asserted harm, are useful precisely because the criticism is expressed in terms that can be quoted back.

Why decisions are indicative rather than binding

There is no doctrine of precedent in planning. Every application and every appeal is determined on its own merits, in accordance with the development plan unless material considerations indicate otherwise.

What the courts have established is narrower and still valuable. Consistency in decision making is itself a material consideration, and a decision maker who departs from a previous decision on the same site or on materially similar circumstances is expected to give reasons for doing so. That does not oblige the council to follow an earlier decision. It obliges the council to engage with it.

The strength of the argument scales with similarity. A previous appeal decision on the same site, on a similar scheme, under the same policy, is powerful. A decision in a different authority on a different scheme type, under a different local plan, is background reading.

Treat the whole category honestly in your submissions. Describing a set of appeal decisions as indicative of how inspectors have approached this issue is accurate and persuasive. Describing them as precedent invites a correction.

Citing a decision in a later application

Cite properly or not at all. A citation that a case officer cannot verify in two minutes is worse than no citation.

1. Give the full appeal reference and the date of the decision.
2. Give the local planning authority and a one-line description of the site and the proposal.
3. State the procedure, whether written representations, a hearing or an inquiry.
4. Identify the paragraph number you rely on.
5. Quote the passage exactly, in quotation marks, rather than paraphrasing it as though it were a quotation.
6. Explain in one sentence why the circumstances are comparable to yours.
7. Acknowledge the material differences, briefly, before the council does.
8. Attach the decision letter as an appendix or give the reference so it can be found on the appeals search.

Two or three well-cited decisions beat a list of ten. And where the council has itself cited a decision, read the whole letter rather than the extract the officer quoted, because the surrounding paragraphs frequently qualify it.

Carry the citations into the Planning Statement rather than leaving them in a covering letter, and where the point is a design judgement, reflect it in the Design and Access Statement as well.

Where reliance on a decision backfires

Five recurring failures.

Citing the outcome without the reasoning, which invites the answer that the facts were different. Citing a decision under superseded policy, particularly anything decided under an earlier edition of the National Planning Policy Framework, without acknowledging the change. Citing a decision in which the inspector expressly confined the finding to the circumstances of that case, which inspectors do deliberately and often. Mischaracterising a finding, which destroys the credibility of every other citation in the document. And citing a dismissed appeal for a favourable paragraph while ignoring the paragraph that dismissed it.

There is a sixth that applies to architects and agents specifically. Relying on a decision about a scheme you designed, on a site you know well, without checking whether the inspector's reasoning actually helps the new case. Familiarity makes it easy to remember the outcome and forget the reasons.

When in doubt, read the letter again with the question in front of you rather than from memory.

Building a small internal library

A library of forty well-indexed decisions is more useful than a folder of four hundred.

Index by issue rather than by site. Useful categories for most practices: character and appearance, overlooking and privacy, daylight and sunlight, highway safety and access, Green Belt, heritage harm and public benefits, housing land supply, conditions and enforcement.

For each entry record the appeal reference, date, authority, procedure, the main issues as the inspector framed them, the policy edition in force at the time, the paragraph numbers worth quoting, and the outcome. Store the PDF rather than a link.

Then review it once a year. Decisions taken under superseded national policy or a superseded local plan need either a caveat or removal, and the National Planning Policy Framework published on 17 August 2026 reorganised the document around policy codes, which makes older citations harder to align. Following policy changes as they happen is easier than reconstructing them later, and the planning law updates timeline is one place to keep track.

One more entry worth keeping: decisions in which the council lost on an issue you expect to face. Those are the ones you reach for when a case officer raises the same point, and our note on neighbour amenity refusals for overlooking and overbearing effect shows how that reasoning gets deployed.

This is general guidance rather than legal advice, so 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.