‘A serious failure’: CPS prosecutor cites imaginary case to high court after AI search

The Crown Prosecution Service (CPS) has admitted that one of its senior prosecutors cited an entirely fabricated legal case during a high court dispute over whether an 11-year-old boy should be prosecuted for the rape of his seven-year-old sister. The error has sparked fresh concerns about AI hallucinations infecting the justice system.

Ravinder Dhillon, representing the CPS, referenced a nonexistent case called CPS – R v J EWCA Crim 3529 during arguments in favor of prosecuting the child. The case adds to dozens of others where AI-related errors have plagued court proceedings this year, though this is only the second known case involving the CPS itself.

Previous AI Error

In February, the CPS admitted that one of its lawyers in an extradition case involving two Romanians had cited nonexistent legal authorities, likely caused by AI. Those made-up cases were only spotted when opposition lawyers could find no trace of them, and the CPS concluded 'the risk of recurrence was low'.

The latest case was particularly concerning because the decision to prosecute the child was taken by Dhillon in April and confirmed by the chief crown prosecutor before the error was discovered in October.

Expert Criticism

Brian Flanagan, associate professor of law at Maynooth University who investigates AI use by judges, called the CPS's explanation 'unsatisfactory' and the error a 'serious failure.' He emphasized that AI increases the risk of such incidents despite the time it can save.

Systemic Concerns

The high court judges noted that the CPS's reference to a fictitious case did not affect the outcome of the boy's challenge to the prosecution decision, which is scheduled for trial in youth courts this week. The incident brings to 101 the number of entries in a UK tracker of AI-related errors in courts.

In June 2025, the high court had already called on legal bodies to address AI misuse 'as a matter of urgency,' warning of serious implications for public confidence in the justice system. Dame Victoria Sharp, then president of the King's bench division, noted that lawyers misusing AI could face sanctions ranging from public admonishment to contempt of court proceedings.

The CPS maintains it has a strict AI policy that limits its use and requires human checks for accuracy. A spokesperson said the error occurred during internet-based legal research and was promptly remedied with an internal review. They emphasized that case law must now be cited only from trusted legal sources.