Court dismisses appeal citing AI-generated fake legal authorities

What happened

Gemma O'Doherty, representing herself without lawyers, used AI to prepare written submissions for an appeal to the Court of Appeal. The AI-generated submissions cited legal authorities that did not exist.

Judge Caroline Costello noted that the submissions included 'hallucinations' of non-existent cases, describing this as 'an inherent and well-known risk' of using AI to write legal papers. The judge rejected the appeal citing these fabricated authorities.

Reported impact

O'Doherty's appeal against the High Court's refusal to strike out defamation proceedings brought by Jimmy Guerin was dismissed. The court ordered a retrial, which had not yet occurred at the time of judgment.

Index analysis

Judge Costello said she did not believe O'Doherty intended to mislead the court or was aware she was citing fictional cases. The judge noted there was no guidance at the time to help self-representing litigants know how they should and should not use AI in their cases.

Governance controls

The judge set out principles that litigants may use AI responsibly to assist with research but must independently verify the accuracy of their submissions. Parties are obliged not to mislead the court by advancing 'fake' propositions, and judges will be able to apply sanctions where AI leads to the court being misled.

The Court of Appeal said litigants should inform their opponents and the court if they have used artificial intelligence to prepare their legal papers.

Classification

Organizations

Gemma O'Doherty (subject), Jimmy Guerin (victim), Court of Appeal (mentioned)

Category

Reliability and hallucination

Industry

Government, security and defence

Country

Ireland

Harm status

Actual harm

Intent

Unintentional

Timing

Post-deployment

Harm types

Reputational

Failure modes

Fabricated citation, Hallucination, Overreliance

Consequences

Litigation

AI systems

Unidentified large language model

Sources and evidence