Sanction teardown · First-tier Tribunal (Property Chamber), UK · 2026-03-09
Chevalier-Hernandez v Poplar Dock Management Company Ltd
What happened
In First-tier Tribunal (Property Chamber), UK, a filing relied on ChatGPT to help draft legal argument. The court identified the following problems with the citations in that filing:
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Fabricated (Case Law)The Applicant cited a purported case supporting the proposition that pest-control treatments were qualifying works under section 20 of the Landlord and Tenant Act 1985. The Tribunal and Respondent could not find the case in any legal database or law report and treated it as a fake authority.
Which AI tool
ChatGPT. Note: Charlotin's public database records tool attribution only where a court order, brief, or reporting on the matter states it explicitly; "unidentified" or "implied" means the record indicates AI use but does not name a specific product — we do not guess.
Outcome
The Applicant withdrew the argument; the Tribunal warned litigants to verify authorities but imposed no sanction.
Additional detail
The Applicant relied on an unidentified purported legal authority claiming that a pest-control programme constituted qualifying works requiring consultation under section 20 of the Landlord and Tenant Act 1985. The Tribunal and Respondent could not locate the case in any legal database or law report, despite the authority containing purported party names, court, date, facts, legal points, judge, and citation. The Applicant withdrew the argument and said he may have found it through Google or ChatGPT. The Tribunal characterized the authority as a fake case and reminded litigants, including litigants in person, to verify that legal authorities are genuine.
How Citation Safe would have caught this
Citation Safe runs three deterministic layers before a brief is filed: (1) does the citation exist against CourtListener's database of published opinions, (2) if quoted, does that exact language appear in the source, (3) does the cited case actually support the proposition it is cited for. Fabricated case citations fail Layer 1. Fabricated or misattributed quotations fail Layer 2 even when the underlying case is real. Misrepresented holdings — a real case cited for a proposition it does not support — are the target of Layer 3. None of these checks involve asking another language model whether the citation looks right; they are lookups and text-matches against the actual source, which is why a hallucinated citation has to survive a direct lookup against the authoritative source — not another model's opinion — to earn a VERIFIED stamp; our measured false-verify rate is published live at /quality.
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Source: https://www.damiencharlotin.com/documents/3026/68_Boardwalk_Place_DECISION_amended_24.02.26.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).