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Incident Tracker / Ireland

Guerin v O'Doherty, [2026] IECA 48

·Court of Appeal (Ireland)·IEDismissal

In the Irish Court of Appeal, self-represented appellant Gemma O'Doherty filed AI-prepared submissions citing authorities that did not exist and never disclosed her use of AI. Costello P dismissed her appeal and issued Ireland's first appellate guidance on AI in litigation: five principles requiring responsible use, disclosure of AI use, and independent verification of every authority.

Court
Court of Appeal (Ireland)
Date
2026-03-26
Who used the AI
Not recorded
AI tool
Not identified in the record
Conduct
A self-represented appellant used AI to prepare her written submissions, which cited authorities that did not exist — described by the court as hallucinations generated by the AI system — and did not tell the opposing solicitors or the court that she had used AI. Counsel wasted time trying to locate the fabricated cases.
Outcome
Dismissal
Penalty
No monetary penalty recorded
Regulatory outcome
No separate regulatory disposition recorded
Status
Verified against listed sources
Last checked
2026-09-11

What was fabricated or misused

  • References to authorities in the AI-prepared written submissions which simply did not exist; the Court did not list the case names

What the court said

“The defendant used AI to prepare the written submissions, which she filed in support of her appeal.”
Court of Appeal (Ireland), [72]
“There were no such cases, and they were not authority for the propositions which they purported to establish.”
Court of Appeal (Ireland), [72]
“No authority should be cited by a party who has not actually verified that it is a genuine judgment of the court and that it is – or at least arguably is - authority for the proposition contended for.”
Court of Appeal (Ireland), [74]
“It casts an unfair burden on the opposing party in their preparation of their response to the submission or in preparing the books of appeal.”
Court of Appeal (Ireland), [75]

Timeline

  1. Defamation trial commenced before a judge and jury.
  2. Jury was unable to agree; the High Court directed a retrial.
  3. Defendant issued a motion to strike out the proceedings.
  4. Court of Appeal heard the strike-out appeal.
  5. Court rejected the appeal and stated principles for AI use.

Why this case matters

Von Geitz, decided ten days earlier, noted suspected AI hallucinations in a self-represented appellant's papers but did not set a general rule. Guerin did. Costello P used a failed defamation strike-out appeal to state five principles for parties who use AI in litigation: disclose the use, verify the authorities, and accept responsibility for the final work. The decision is narrower than Ayinde because it concerned a litigant in person rather than lawyers, but it supplied Ireland's first appellate guidance directed to all parties.

Practice note

A party using AI for legal research should tell the opposing party and the court before relying on that work. Each authority should be opened in the reported judgment, checked for existence, and checked against the sentence it is said to support. If the party cannot complete that check, the authority should not be cited.

Primary sources for this incident

Related regulation records for this incident

Similar incidents on the record

  • Von Geitz v Kelly & Ors; Von Geitz v Robertson & Ors, [2026] IECA 292026-03-16 · Court of Appeal (Ireland) · DismissalIn the Irish Court of Appeal, Allen J found self-represented plaintiff Juerg Von Geitz's submissions across two appeals contained unsupported propositions, wrong citations and 'a few non-existent cases' suggested to be…
  • Ferko v Beyond Reach Ltd t/a Car Wash Crew, ADJ-000606222026-03-02 · Workplace Relations Commission · DismissalBefore Ireland's Workplace Relations Commission, complainant Imrich Ferko's complaint form was prepared by his sister using AI, and he admitted not verifying it before submission. Adjudication Officer Christina Ryan gav…

Cite this record

SafeLegalAI Global Legal AI Incident Tracker, “Guerin v O'Doherty, [2026] IECA 48”, safelegalai.com/tracker/guerin-v-odoherty (accessed 2026-09-16). Data: CC BY 4.0.

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