CPS Prosecutor Cited Nonexistent Case After AI Search Error

A senior Crown Prosecution Service prosecutor cited an entirely imaginary legal precedent before the High Court in London after an internet search returned an AI-generated summary containing fictional case details. Two senior High Court judges called Ravinder Dhillon's explanation for the error "unsatisfactory," and an academic expert branded it "a serious failure."

Dhillon, a senior crown prosecutor in the CPS's rape and serious sexual offences unit, was arguing for the prosecution of a boy who was 11 at the time of the alleged rape of his seven-year-old sister. She submitted a detailed reference to a case styled CPS – R v J [2024] EWCA Crim 3529. It did not exist.

What happened in the case?

Lawyers for the boy were challenging the CPS's decision to prosecute him. They alleged prosecutors had failed to take into account representations from social workers, youth workers and a forensic psychologist. Dhillon took the decision to proceed in April, and the chief crown prosecutor confirmed it.

In October, Dhillon admitted the citation had been made in error. She said she had intended to refer to a completely different decision — a real one — made 15 years earlier. The Guardian understands the reference came from an AI response generated during an internet search.

The High Court said the fictitious citation did not affect the outcome of the boy's challenge. His prosecution is listed for trial in the youth courts later this week.

How serious is the failure?

Brian Flanagan, associate professor of law at Maynooth University in Ireland, who investigates the use of AI by judges, did not mince words. "This was used as a legal source to argue for the prosecution of a child and that legal source doesn't exist: that's a serious failure," he said.

He warned the episode corrodes basic norms of legal trust. "It calls into question norms of trust in the law where we treat authorities as precious things. You can't make them up; it's out of bounds," Flanagan said, adding that AI increases that risk "because of the time you can save." He drew a sharp distinction between private practitioners and state lawyers: "It is not great for any professional to do this, but when the professional is working for the state it takes on a different aspect, because the power of the state is immense."

Is this the first CPS incident?

No. This is only the second known case involving the CPS, the main public agency bringing criminal prosecutions in England and Wales. In February, the CPS admitted that one of its lawyers, acting in an extradition case involving two Romanians convicted of minor offences, cited nonexistent legal authorities, likely caused by AI. Opposition lawyers spotted those fabricated cases only when they could find no trace of them. The CPS then concluded "the risk of recurrence was low."

The latest episode brings to 101 the number of entries in a UK tracker maintained by Doughty Street Chambers barrister Matthew Lee, covering confirmed, suspected and disputed AI-related errors and related false citations. Lee said the identified cases may be the "tip of the iceberg," because many lower court decisions are never published. This year has seen dozens of similar errors plague court proceedings, mostly from litigants in person, often in employment tribunal cases.

What did the CPS say?

A CPS spokesperson said the service has a strict AI policy "which limits its use so that it is not used to make legal decisions and there must be human checks for accuracy."

The spokesperson said the CPS "identified an error had occurred from conducting legal research using the internet." The statement continued: "As soon as this error was identified, it was remedied and an internal review was carried out to establish how this had occurred and to check that no other cases have been affected. Following the rapid review we shared learnings, including that case law must be cited from trusted legal sources."

What does this mean for practitioners?

The incident lands amid an escalating judicial response. In June 2025, the High Court, responding to AI hallucinations in cases spanning housing to banking, called on the Bar Council and the Law Society to consider curbing the problem "as a matter of urgency." Dame Victoria Sharp, then president of the King's Bench Division, warned of "serious implications for the administration of justice and public confidence in the justice system if artificial intelligence is misused." She said lawyers misusing AI could face sanctions ranging from public admonishment to contempt of court proceedings and referral to the police.

Lee also flagged privacy and confidentiality risks from CPS use of AI, given the highly sensitive information the service handles. He warned that AI is creating additional work for barristers, who now must verify the authenticity of legal authorities appearing in case papers wherever AI may have played a role in their preparation.