Judicial Guidance On AI Use In Litigation

In its recent decision in Guerin v O’Doherty [2026] IECA 48 (“Guerin”), the Irish Court of Appeal set out general principles for the use of AI in litigation. The court stressed that all parties to litigation (whether legally represented or not) have an obligation not to mislead the court by relying on fabricated authorities or unsupported propositions.  The judgment highlights some of the risks associated with the use of generative AI in conducting litigation.

Hallucination risk and impact

The defendant (a litigant in person) used AI to prepare their written submissions. This resulted in the submissions referencing authorities that did not exist, as a result of so-called “hallucinations”. The court observed these types of issues should be expected, given the nature of large language model (“LLM”) artificial intelligence systems.