A judge has warned of the risks of using AI in court hearings after documents from the Crown Prosecution Service (CPS) contained references to “non-existent” legal cases.
Mr Justice Sweeting issued the warning in a ruling on Wednesday, where he dismissed the appeals of two people challenging decisions to extradite them to Romania to serve sentences for offences committed there.
The CPS opposed the appeals at the High Court.
At the end of his judgment, Mr Justice Sweeting said that two legal authorities cited by the CPS in a document that formed part of their case did not exist.
He continued that the two cases were then cited in another document, before the issue was raised with the CPS prior to a hearing in February.
The CPS acknowledged and apologised for the error, stating that it had not sought to mislead the court and that inquiries were being undertaken into how the error was made.
The judge said that, in a letter in March, the CPS accepted that the references to the cases were inaccurate and “explained that they were likely to have originated from the use of artificial intelligence”.
“However, the CPS identified the critical failing as the fact that the reviewing lawyer did not properly check the accuracy of the document before it was filed and served,” the judge said.
He continued: “The position of the CPS was therefore that, while the immediate source of the error may have been the use of generative artificial intelligence, the operative cause was human error in the failure to verify the authorities relied upon in formal submissions placed before the Court.
“The CPS emphasised that this was not a deliberate attempt to mislead, but rather an isolated incident arising from inadequate checking of written work.”
Mr Justice Sweeting also said that the CPS had conducted a full internal review into the incident and reviewed 78 other cases linked to the same lawyer, which identified no concerns and led it to believe there was a low risk of it happening again.
He concluded: “As far as the appeal was concerned, the errors came to light prior to the hearing and therefore had no impact on argument or the court’s judgment.
“I have accepted the apology given on behalf of the CPS and the assurance that there was no attempt to mislead.”
He continued: “It would be naIve to assume that there will not be an increasing use of artificial intelligence in legal work in future; indeed, that may be both necessary and beneficial.
“The episode highlights the risks of its use without appropriate oversight, particularly for legal research.”
The CPS has been approached for comment.
