A lawyer cited an AI-fabricated High Court authority before the NSW Court of Appeal
In Edmonds v Barrington Winstanley Group (No 3) [2026] NSWCA 31, a lawyer filed written submissions that cited a non-existent High Court authority and alleged the uploading of a non-existent mortgage (AU379627) among other documentary irregularities. The court identified the fabricated citation and noted it did not correspond to any real case. The AI tool was implied but not specifically confirmed by the court.
An AI model conjured a non-existent High Court authority and a phantom mortgage registration, which the lawyer filed without verification.
Key facts
- What
- In Edmonds v Barrington Winstanley Group (No 3) [2026] NSWCA 31, a lawyer filed written submissions that cited a non-existent High Court authority and alleged the uploading of a non-existent mortgage (AU379627) among other documentary irregularities.
- Incident date
- Mar 18, 2026
- Who
- Edmonds v Barrington Winstanley Group (legal representatives)
- Failure mode
- Hallucination
- AI surface
- Copilot
- Severity
- Medium
What happened
In Edmonds v Barrington Winstanley Group (No 3) [2026] NSWCA 31, decided on 18 March 2026, the applicants' lawyer filed written submissions that cited a non-existent High Court authority. The court noted the citation did not correspond to any such case and directed it to a different case entirely. The submissions also alleged the uploading of a non-existent mortgage (AU379627) among other asserted documentary irregularities. The court issued a warning regarding the use of AI-generated material, with the AI tool classified as implied rather than specifically identified.
What broke inside the model
- 01 · TriggerA user asks for a fact, a citation, or a figure.
- 02 · Model stepThe model writes a fluent, confident answer.
- 03 · Control gapNothing ties the claim back to a real source.
- 04 · FailureA fabricated fact ships as if it were verified.
- 05 · ConsequenceThe false claim reaches a customer, a court, or the public.
Confidence holds, and even spikes, as the claim detaches from any source.
The generative AI model produced plausible-sounding legal citations and documentary claims with no basis in reality, including a fabricated High Court authority and a phantom mortgage registration number. The lawyer failed to independently verify the AI-generated content against authoritative legal databases before filing it with the court, allowing hallucinated authorities to be presented as legitimate precedent.
What it cost
Sources
- Court FilingEdmonds v Barrington Winstanley Group Pty Ltd (No 3) [2026] NSWCA 31 (Court of Appeal of New South Wales)damiencharlotin.com
- PrimaryAI Hallucination Cases Database - Damien Charlotindamiencharlotin.com
- Reader-SubmittedEdmonds v Barrington Winstanley Group - Christian Kameir AI Legal Research Trackerkameir.com
Cite this entry
https://failureindex.ai/failures/lawyer-cited-ai-fabricated-high-courtAI Failure Index. "A lawyer cited an AI-fabricated High Court authority before the NSW Court of Appeal" (FI-0135). Realm Labs. https://failureindex.ai/failures/lawyer-cited-ai-fabricated-high-court (indexed Jun 4, 2026).Data fields CC-BY 4.0, prose citation permitted. Incident ID FI-0135. Full dataset at /data.
Note from Realm Labs, the Index steward
How Realm would have caught this
- Prism
- OmniGuard
- AI Detection & Response (AIDR)
A runtime layer that watches the model's internal state can flag the moment a model commits to a claim it has no support for, and hold or reroute the response before it reaches a user. Realm reads those signals in real time rather than grading the transcript after the fact.