CPS Prosecutor Cited an Imaginary Case in the High Court After an AI Search

A senior Crown Prosecution Service lawyer cited a legal case that does not exist while arguing in the High Court, and the reference appears to have come from an AI summary produced during an internet search. The Guardian reported the story on 3 November 2026, and two High Court judges described the explanation for the mistake as unsatisfactory. It is the latest warning about what happens when AI tools invent sources that look real enough to reach a courtroom.

What the prosecutor cited

The prosecutor was Ravinder Dhillon, a senior crown prosecutor in the CPS rape and serious sexual offences unit. She was arguing in favour of continuing a prosecution, and she submitted a detailed reference to a case she called CPS, R v J [2024] EWCA Crim 3529. The citation had everything a real authority is supposed to have: a year, a court, and a case number. It had no judgment behind it, because the case was never decided. It does not exist. The Guardian understands the reference came from an AI response generated during an internet search, and nobody checked the citation against a proper legal database before it reached the court.

The underlying case concerned a boy who was 11 at the time of the alleged rape of his seven-year-old sister. The decision to proceed was taken by Dhillon in April and confirmed by the chief crown prosecutor. In October she admitted the error, saying she had meant a real decision from 15 years earlier. The High Court said the fictitious reference did not affect the outcome of the boy's challenge, and the trial was still listed for the youth courts later that week.

How the court reacted

Two senior judges heard the challenge, and their view of the explanation was blunt. They called it unsatisfactory.

The judgment in the challenge was published as EWHC/Admin/2026/2778. The court papers show the invented citation sitting in the material put before the judges, presented as if it supported the decision to prosecute. A court can only do its job if the authorities cited to it are real, and a fake citation wastes the court's time and damages trust in the process.

Brian Flanagan, an associate professor of law at Maynooth University who studies how judges and lawyers use AI, described the incident as a serious failure. His point was direct: the invented authority was used as a legal source to argue for the prosecution of a child, and that source does not exist.

This was not the first CPS case

The Guardian reports that this is only the second known case of its kind at the CPS. The first came in February 2026, when one of its lawyers acting in an extradition case involving two Romanians convicted of minor offences cited nonexistent legal authorities, in circumstances also linked to AI. The CPS carried out a review after that incident and concluded that the risk of it happening again was low. Less than a year later, it happened again.

The pattern is wider than the CPS. In June 2025, the High Court dealt with AI hallucinations in cases spanning housing to banking, in Ayinde v London Borough of Haringey and Al-Haroun v Qatar National Bank. The court treated the citing of fictitious cases as wrong even where the legal principle pinned to the fake authority happened to be correct, and it called on the Bar Council and the Law Society to consider steps to curb the problem. A tracker maintained by Doughty Street Chambers barrister Matthew Lee now lists 101 entries covering confirmed, suspected and disputed AI-related errors as well as related false citations in UK courts.

What the CPS says about its AI rules

The CPS says it has a strict AI policy which limits the use of AI so that it is not used to make legal decisions, and requires human checks for accuracy. A spokesperson said the service identified an error that had occurred from conducting legal research using the internet, that the error was remedied once identified, and that an internal review looked at how it happened and whether other cases were affected.

That account raises an obvious question. If the policy already requires human checks, why did a citation invented by an AI summary reach the High Court? The reporting does not answer that question, and the CPS has not said what the internal review found in detail. The gap between the written policy and what happened in practice is now the central issue, and a rule that is not followed at the point of use is not a safeguard.

Why AI invents citations

The failure has a name in the AI industry: hallucination. Language models predict the next words in a sequence, and when they are asked for a citation they can produce one that follows all the conventions of a real reference while pointing at nothing. A citation with a year, a court and a number looks complete, and that is exactly what makes it dangerous.

Search engines now put AI summaries at the top of results pages, which makes the risk harder to spot. A lawyer, a journalist or a business owner who reads the summary at the top may never click through to the source. The summary feels like the answer, and the answer feels checked. In this instance the summary was wrong, and the error travelled from a search box into a High Court hearing before anyone noticed.

Frequently Asked Questions

What case did the CPS prosecutor cite that does not exist?

She cited a case called CPS, R v J [2024] EWCA Crim 3529 while arguing in the High Court in favour of prosecuting a child. The case does not exist. The Guardian understands the reference came from an AI response generated during an internet search, and the prosecutor later admitted the citation was made in error.

Did the fake citation change the outcome of the case?

No. The High Court said the fictitious reference did not affect the outcome of the boy's challenge to the decision to continue with the prosecution, and the trial was still listed for the youth courts later that week. Two judges still described the explanation as unsatisfactory.

Has this happened before in UK courts?

Yes. The CPS had a similar case in February 2026, when a lawyer in an extradition case cited nonexistent authorities in circumstances also linked to AI. A tracker kept by Doughty Street Chambers barrister Matthew Lee lists 101 such errors and false citations in UK courts.