Spotting invented case law in a planning document

A fabricated case law planning report usually looks right. The party names are plausible, the year is plausible, the neutral citation has the correct shape, and the proposition it is cited for is one a planning lawyer might well argue. The only way to know is to look it up, and the practical answer for any practice producing drafted documents is a rule that no citation leaves the office unverified.

Two failure modes matter, and the second is more common than the first. A citation that does not exist at all. And a citation that exists but does not say what the document claims it says. The second slips through more often, because a reviewer who finds the case assumes the point is good.

Why citation errors appear in generated text

Language models generate text that resembles the training distribution, and legal citations have a highly regular form. A plausible citation is therefore easy to produce and indistinguishable on its face from a real one. The model is not consulting a database of judgments when it writes one.

The same mechanism produces misattribution. Where a proposition is strongly associated with a particular line of authority, a citation from that area can be attached to a claim the judgment does not support, and the result reads as confident and specific.

Policy references fail the same way, and in planning that is the bigger practical risk. The National Planning Policy Framework was renumbered in December 2024 and reissued on 17 August 2026 with policy-coded chapters in place of paragraph numbers. A document carrying a paragraph number from an older edition is wrong in a way that is immediately visible to a case officer, and generated text drawn from older material will tend to reproduce the old numbering. Always state the edition you are citing and check the current Framework at the time of writing.

PlanScope's drafting inserts "[TO BE CONFIRMED]" where it lacks a site-specific fact rather than inventing one, and the equivalent discipline for citations is to leave the reference blank and flag it rather than to produce something that looks finished. The wider pattern is set out in what drafts get right about structure and wrong about evidence.

Checking a judgment against the official record

Neutral citations are the quickest check because they are structured and unique. A High Court planning judgment carries the form [2023] EWHC 1234 (Admin), the Court of Appeal [2023] EWCA Civ 456, and the Supreme Court [2023] UKSC 12.

Find Case Law, run by The National Archives, holds judgments and is the authoritative free source for recent ones. BAILII covers a longer period and remains useful for older authorities. Four checks take a minute each.

1. Does the neutral citation resolve to a judgment at all.
2. Do the party names on that judgment match the ones in your document.
3. Is the court consistent with the type of claim: a planning statutory review or judicial review sits in the Administrative Court, not in the Court of Appeal at first instance.
4. Does the paragraph cited contain the proposition. Read it, rather than scanning for the party names.

The fourth check is the one that catches misattribution, and it is the one most often skipped under deadline pressure. If the paragraph number does not exist in the judgment, or the paragraph says something adjacent but narrower, the citation has to come out.

Appeal decisions and their reference format

Planning appeal decisions have their own reference structure, in the form APP, then a code for the local planning authority, then a letter for the appeal type, then the year, then a case number. The letter tells you what kind of appeal it was, with W used for planning appeals under section 78 and D for householder appeals, among others.

Three parts of that reference are checkable without reading the decision. The authority code should correspond to the authority the decision is attributed to, so a decision said to concern a London borough carrying a code used by a Midlands district is wrong. The appeal type letter should match the kind of decision described, since an enforcement appeal reference attached to a refusal of planning permission is an error. And the year should sit before the date the decision is said to have been issued.

Appeal decisions are published by the Planning Inspectorate and are searchable, and most authorities also publish decisions relating to their own area. Where a decision cannot be found by reference or by site address, treat it as unverified and remove it.

Invented appeal references tend to give themselves away through implausible case numbers, since the numbering follows conventions that a generated reference rarely reproduces exactly.

Reported, unreported and the weight each carries

A judgment is a judgment whether or not it appears in a law report, and a neutral citation is enough to identify it. Reporting in a series signals that an editor thought the case established something, which is a useful filter when you are choosing between authorities but not a condition of citing one.

Appeal decisions sit in a different category again. They are decisions on the facts of a particular site by an inspector exercising the same judgement a planning officer exercises, and they are published in volume. Selecting the three that support your case out of thirty on similar facts is advocacy, and an experienced officer or inspector will recognise it.

The honest way to use them is to say what the decision turned on and why the facts are comparable. The version that fails is a list of references with one-line summaries, which invites the reader to check whether the summaries are accurate.

Why appeal decisions are not binding precedent

An inspector's decision binds nobody beyond the appeal it decides. It is a material consideration, and the courts have held, in the line of authority running from North Wiltshire, that consistency matters enough that a decision maker should give reasons for departing from a previous decision on the same or a materially similar case.

That is a long way from precedent. It means a relevant earlier decision cannot simply be ignored, and it does not mean the earlier conclusion must be followed. Presenting an appeal decision as though it settles a point is a mistake that practitioners make without any help from software, and it weakens an otherwise sound document.

Judicial authority is different, and the distinction is worth stating plainly in a Planning Statement where it arises. A judgment on the interpretation of a policy or a statutory provision binds decision makers on that interpretation. An appeal decision on whether a particular scheme harmed a particular street scene does not.

Correcting a document before submission

When a bad citation is found, three decisions follow in order.

Remove it. A document is stronger with a plainly stated proposition and no citation than with a citation that cannot be verified, because the unverifiable reference calls everything else into question.

Then ask whether the point survives. Often it does, on policy or on fact, and the reference was decoration. Sometimes the point existed only because the citation seemed to support it, in which case the argument has to change.

Then check the rest of the document. Citation errors cluster, because they arise from the same process. Finding one is a reason to verify every reference rather than to fix the single instance. Where sections have been regenerated at different times, version discipline matters, and version control when report sections are regenerated sets out how that goes wrong.

Where the document has already been submitted, correct it in writing to the case officer rather than waiting to be asked. Officers deal with errors constantly and respond well to a straightforward correction. They respond badly to discovering one themselves.

A verification habit for a practice

Four rules cover most of the risk, and none of them takes long.

No citation enters a document until someone has opened the judgment or decision and read the paragraph relied on. Every cited authority goes in a short register against the document, with the link and the date checked, so that a reviewer can repeat the check without starting again. Every policy reference states the edition or version and the date it was verified. And nobody cites from memory in a document that goes to a local planning authority, however familiar the case.

Under appeal deadlines this discipline is the first thing to go, which is exactly when the consequences are worst, and drafting to an appeal deadline without cutting corners covers how to protect it. Where a document carries legal argument of any weight, having it reviewed by a suitably qualified professional before submission is the sensible final step, and you can arrange that through the professional directory.

This is general guidance, not legal advice, and nothing here is a substitute for taking advice on a specific case. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.