A close reading of the "AI" fake cases judgment

Why it is the very plausibility of AI-generated case law that should put lawyers on their guard

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Consider five cases recently cited in a High Court housing judicial review in London:

• R (on the application of Ibrahim) v Waltham Forest LBC [2019] EWHC 1873 (Admin)

• R (on the application of KN) v Barnet LBC [2020] EWHC 1066 (Admin)

• R (on the application of El Gendi) v Camden London Borough Council [2020] EWHC 2435 (Admin)

• R (on the application of H) v Ealing London Borough Council [2021] EWHC 939 (Admin)

• R (on the application of Balogun) v London Borough of Lambeth [2020] EWCA Civ 1442

On the face of it, what can we say about these five cases?

Well, first, they have mundane - indeed boring - names. The sort of case names that one would expect to exist in everyday cases. These are case names to which one would not give a second glance.

Second: you can also see that each case is against a London council, with that council status set out in three different ways - “LBC”, “London Borough of [x]” and “[y] London Borough Council”. Such variation is common on case names. And as housing judicial review cases, the defendant being a local council is what one would expect.

Third: they are in the correct case style - in four cases the “R (on the application of [x]” bit at the beginning of the case name matches the “(Admin)” bit at the end - for this is the usual way for the names of judicial review cases in the Administrative Court to be set out. And this form often survives when a case goes to the Court of Appeal - so that fifth case does not look unusual either.

Had the cases been placed in the, say, family court or patent court then those case names and citations would look odd - but here, all so normal, all so unexceptional.

Fourth: even the case numbering is plausible and within the range for the year in question - eg, the Administrative Court had at least 3562 numbered cases in 2020 - and so a 2020 case numbered 2435 would not seem strange.

And fifth: they are all recent (2020 onwards) cases against local authorities - again, exactly what one would expect to see in a legal submission in a case about local councils in a well-litigated, always-moving area like housing. You would expect to see a bias towards recent cases to illustrate legal points in this context.

So all the cases not only look look normal, but they are plausible names and citations for housing judicial review cases.

And they are not only superficially plausible, they are deeply plausible and on many levels.

There is nothing inherent in that list of case names and citations that would make any experienced lawyer doubt that they exist.

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Now let us move on to how these five cases were used in the High Court case submissions by the claimant’s lawyers, so as to illustrate legal points (case names emphasised):

"Moreover, in R (on the application of Ibrahim) v Waltham Forest LBC [2019] EWHC 1873 (Admin), the court quashed the local authority decision due to its failure to properly consider the applicant's medical needs, underscoring for necessity the careful evaluation of such evidence in homelessness determinations. The respondent's failure to consider the appellant's medical conditions in their entirety, despite being presented with comprehensive medical documentation, renders their decision procedurally improper and irrational".

"The respondent's failure to provide a timely response and its refusal to offer interim accommodation have denied the appellant a fair opportunity to secure his rights under the homelessness legislation. This breach is further highlighted in R (on the application of KN) v Barnet LBC [2020] EWHC 1066 (Admin) where the court held that procedural fairness includes timely decision-making and the provision of necessary accommodation during the review process. The respondent's failure to adhere to these principles constitutes a breach of the duty to act fairly."

"In R (on the application of El Gendi) v Camden London Borough Council [2020] EWHC 2435 (Admin), the High Court emphasised that failing to provide interim accommodation during the review process undermines the protective purposes of homelessness legislation. The court found that such a failure not only constitutes a breach of statutory duty but also creates unnecessary hardship for vulnerable individuals. The respondent's similar failure in the present case demonstrates a procedural impropriety warranting judicial review."

"The appellant's situation mirrors the facts in R (on the application of H) v Ealing London Borough Council [2021] EWHC 939 (Admin) where the court found the local authority's failure to provide interim accommodation irrational in light of the appellant's vulnerability and the potential consequences of homelessness. The respondent's conduct in this case similarly lacks a rational basis and demonstrates a failure to properly exercise its discretion."

"The appellant's case further aligns with the principles set out in R (on the application of Balogun) v London Borough of Lambeth [2020] EWCA Civ 1442 — where the Court of Appeal emphasise that local authorities must ensure fair treatment of applicants in the homelessness review process. The respondent's conduct in failing to provide interim accommodation or a timely decision breaches the standard of fairness".

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Again there is nothing glaringly untoward on the face of these passages.

For example, a case with a High Court citation is placed in the High Court, and the case with the Court of Appeal citation is placed in the Court of Appeal.

These are the sort of passages which are set out in hundreds of legal submissions every day - where case law used to demonstrate or show legal points.

Indeed the language employed - “further highlighted in”, “mirrors the facts”, “aligns with the principles set out in” - even shows a pleasing variation in style in using cases to support legal points.

So not only are the case names and citations mundane and plausible, so are the uses to which the cases are put in the submission.

There is nothing on the face of the case names, their citations and the way they are deployed in the submissions which would alert anyone but a deep specialist (who would simply not recognise the cases in their specialised heavily litigated area of law) that something was not right.

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But.

None of these five cases exist.

All five cases are fake.

All five cases are fabricated.

Notwithstanding the plausibility of the case names, and the citations, and the legal points they are attractively used to support - all are mere inventions.

It would take a skilled human forger to come up with such plausible names and citations and legal points.

Or it would take something else.

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The five cases - non-cases - referred to above are, of course, from the unhappy recent case of Ayinde, R (On the Application Of) v The London Borough of Haringey [2025] EWHC 1040 (Admin) - a case which (unfortunately for some of those involved) certainly does exist, though the facts of the case are such that one would think it was invented.

I have written about this case over at Prospect this week - please click and read here - and it is an extraordinary case.

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But first, here are the ordinary - that is, not extraordinary - features of the case.

The claimant was a homeless man challenging his local authority so that he can be housed. One good thing about this case was that he was housed during the litigation, and so for him (at least) the case worked out well. Justice was served from his perspective, and he suffered no prejudice (and gained no advantage) because of what else happened in this case.

The defendant local authority were dire - at least in the litigation - and were so woeful in the conduct of the case they even managed to be disbarred from defending the claim. Nothing in this case is to the credit of the local authority. Quite rightly the costs of the claim were made against the local authority. Again, such conduct by a local council in a case like this is not surprising.

Furthermore the merits of the case were to the advantage of the claimant, including the medical evidence.

This was thereby a case where the claimant was in a strong position, regardless of the haplessness of the local authority.

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And it is now the case becomes odd.

The claimant’s lawyers put in legal submissions which rested on various cited cases - and these cited cases included the five fake cases above.

The legal points these cases were used for by the claimant’s lawyers - see the passages above - were mainly for illustration, rather than to assert and rely on a binding precedent - and one suspects real cases were available to illustrate those very same points.

In other words: there was probably no need to invent any case for the purposes of the submissions. Genuine cases, no doubt, could have been available to illustrate the same points.

And so there is no obvious benefit from inventing cases - it was not as if any of the fabricated cases were a game-changer which would turn the claim from losing to winning. Indeed, it looked as if the claim would have succeeded anyway.

As the judge in this matter says at one point in the judgment:

“The submission was a good one. The medical evidence was strong. The ground was potentially good. Why put a fake case in?”

Why indeed?

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We do not know with absolute certainty how this situation arose.

The judge in this case did not need to probe that deeply - it was for him enough for him that the cited cases were fake, and that there was no good reason for the fake cases to be cited.

The judge therefore used the rare “wasted costs jurisdiction” to award costs against the claimant’s lawyers personally.

The judge also ordered that his judgment be published, which means it is now a signal to all legal practitioners of what is at stake if fake cases are relied upon.

Of course - if you think about it - there will be a limit to what wasted costs can be awarded in respect of fake cases, for the other side can hardly charge for time reading cases that do not exist - but wasted costs orders are something which all lawyers should and do take seriously.

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Of course, there is a plausible explanation for what happened - and it is indeed also the most charitable explanation for what happened.

And that explanation is that the claimant lawyers used some form of Artificial Intelligence (AI) - in particular a large language model (LLM - and not Master of Laws!) like ChatGPT, which superficially is like a search engine.

The judge in this case mentioned that such AI was a possibility, but he did not make a finding.

But the AI/LLM explanation makes sense.

The sheer boringness and plausibility of the case names and citations and the ways the cases were employed suggest either a master human forger or a well-stocked/well-educated LLM. It would otherwise be hard to come up with things that, well, normal-sounding.

There is also the singular fact that the claimant lawyers gained no advantage from the fake cases - they had a strong case anyway, where the defendant was not even able to put in a defence, and with strong medical evidence. None of the five fake cases seemed to be determinative of the case, and they were such that real cases probably would have been done.

The claimant lawyers themselves probably did not realise to a late stage that the cases were fake.

The lack of any advantage gained, and the plausibility of the cases, point to a LLM search engine generating legal hallucinations.

There is no other explanation which fits the available information.

(And readers of this blog will recall the Christmas story where AI came up with a superficially plausible but false author and book.)

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This case is now being used as morality story - to warn lawyers not to rely on AI in their legal research.

Over at his blog Richard Moorhead protests that that this is not actually an AI case - and in one sense he is right, as there was no finding of fact that AI was used.

But that is perhaps like saying that the hallowed negligence case of Donoghue v Stevenson was not about a snail in a bottle of ginger ale because it seems that allegation was never actually proved at trial. Yet it is still known as the snail in the ginger ale bottle case.

And this is destined to be known as the “AI” fake cases judgment - used to warn and terrify generations of lawyers to come.

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For this is very much a case about AI - in that even if AI was somehow (implausibly) not used to invent those five cases, then the effects of those fabrications are very much what would happen if the lawyers had used AI.

And the sheer plausibility of the cases and their citations and the legal points they were used to illustrate are very much what lawyers should be on their guard against with AI LLMs.

The results of queries given to LLMs can be very plausible indeed.

They were not scarily outlandish, but scarily normal.

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Finally, this post will make three further observations and points about this case.

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First, the fake cases only really came to light because on the eve of the hearing, the defendant lawyers made an application for wasted costs (even though they were disbarred from mounting a defence).

This application for wasted costs was such that it was intended - mischievously - to offset the costs that would be awarded against the council for their own woeful conduct of the case.

In other words, the fakery came to light because it was tactically useful to a party to a case for it to do so.

The fake cases were in a document dated August 2024 but were not spotted as problematic until February 2025. Until then they had not been checked by anybody.

This suggests that such fake cases may be more widespread - but just not noticed.

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Second: the conduct of the claimant lawyers when challenged - a remarkable letter and evasions in court, doubling-down - made things far worse. Had the lawyers promptly said there had been a fundamental error because of the searches/queries made, and provided alternative authorities, and apologised, then a court may have been less harsh.

Under-resourced parties to litigation can make errors: the important thing is to correct them promptly.

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Third: you may also have noticed I have not named the lawyers or the parties - that is because I did not need to do so for the purposes of this blog, and I usually shy away from personalising thing in blogposts generally (at least lower than Cabinet level).

Here the import of this case is not just about lawyers in a particular case - the exceptional way in which this instance came to light indicates there may be a more widespread problem, where plausible looking things do not get a second look.

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My own view is that AI/LLMs can do certain simple law-related tasks, but legal research is something which always requires a human mind, and it is something fundamental to being a lawyer.

Some would say using AI/LLMs for legal research is fine, as long as you check the results before relying on them.

My view is that, given the current state of AI/LLMs, that even doing this is dangerous, as the results can looks so plausible you may think they don’t need checking.

You will not notice anything wrong.

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For further reading on this case, see this by David Burrows and also this by Gordon Exall at the estimable Civil Litigation blog.

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