Key facts
- The Crown Prosecution Service (CPS) submitted documents in an extradition appeal citing two non-existent legal cases generated by AI.
- The CPS stated the "operative cause" was human error due to a lawyer failing to verify the AI citations.
- The prosecutor issued two apologies to the High Court.
- The fake cases were discovered before the hearing and did not affect the outcome.
- The judge included the incident in the public record as a warning about AI use in legal research without oversight.
British courts have had to address instances of 'AI hallucination' evidence, with the Crown Prosecution Service (CPS) being the latest agency to submit documents containing fictitious legal cases. The CPS issued two apologies to the High Court after it was discovered that documents in an extradition appeal cited two non-existent legal cases generated by artificial intelligence. The agency attributed the error to human error, stating that a reviewing lawyer failed to verify the citations before submission. The CPS emphasized that this was not a deliberate attempt to mislead but an isolated incident resulting from inadequate checking of written work. The prosecutor had to issue a further apology after admitting that its own junior counsel had identified the fake cases internally before the appellants' counsel did. Mr Justice Sweeting accepted the apologies and the assurance that there was no intent to mislead. Although the fake cases did not impact the outcome of the appeal as they were found before the hearing, the judge decided to include the incident in the judgment's public record to serve as a warning about the risks associated with using AI for legal research without proper human oversight. The judge noted that while AI may be beneficial in future legal work, the episode underscores the necessity of appropriate oversight.