What was hallucinated

Fabricated: Case Law | Respondent cited 'Petzl v Avison [2014] UKUT 0065 (LC)'; tribunal could not find this case and noted it may be inauthentic. || Fabricated: Case Law | Respondent cited 'Fairman v UKCC [2014] UKUT 479 (LC)'; tribunal could not find this case and considered it may be inauthentic. || Fabricated: Case Law | Respondent cited 'Ellis v APL Co Ltd [2011] EWCA Civ 1088'; tribunal was unable to find this authority and suggested it may be AI-generated. || Misrepresented: Case Law | Respondent cited 'Anchor Trust v Wandsworth LBC [2007] EWCA Civ 1051' but tribunal found the citation related to Mohanaei v Mohanaei and the summary given by Respondent was inaccurate. || Misrepresented: Case Law | Respondent cited 'Willmott Dixon Housing Ltd v Secretary of State [2009] EWCA Civ 1044' but tribunal found that the reference corresponds to Pablo Star Ltd v Emirates Integrated Telecommunications Co PJSC [2009] EWCA Civ 1044 and is not authority for the asserted proposition. || Misrepresented: Case Law | Respondent cited 'Osborn v Parole Board [2013] UKSC 61 [2] [68]-[72]'; tribunal noted the full judgment concerns parole hearings and that the passages cited did not appear relevant to the Respondent's argument. || Misrepresented: Case Law | Respondent cited 'Sheffield City Council v Oliver [2017] UKUT 349 (LC)'; tribunal suggested the Respondent may have intended Oliver v Sheffield City Council [2017] EWCA Civ 225 and that the UKUT citation/summary was inaccurate. || Misrepresented: Case Law | Respondent cited 'Waaler v London Borough of Hounslow [2017] EWCA Civ 45' but tribunal stated the Respondent's summary of the case was inaccurate (misstated the legal test). || Misrepresented: Case Law | Respondent cited 'Garside v RFYC Ltd [2011] UKUT 367'; tribunal noted mixed judicial consideration and did not accept the Respondent's claimed authoritative proposition. || Fabricated: Case Law | Respondent cited 'Lambeth LBC v O’Kane [2013] UKUT 0538 (LC)'; tribunal could not locate this citation and flagged potential inauthenticity. || Misrepresented: Case Law | Respondent cited 'Forcelux Ltd v Sweetman [2001] EWCA Civ 1217' but tribunal found that the citation corresponds to Director General of Fair Trading v Proprietary Association of Great Britain (Costs) and that the Respondent's summary did not match the true authority.

Sanction teardown · Property Chamber, UK · 2025-07-07

Various Leaseholders v Assethold Limited

What happened

In Property Chamber, UK, a filing relied on an unnamed/unconfirmed AI tool to help draft legal argument. The court identified the following problems with the citations in that filing:

Fabricated (Case Law)

Respondent cited 'Petzl v Avison [2014] UKUT 0065 (LC)'; tribunal could not find this case and noted it may be inauthentic.
Fabricated (Case Law)

Respondent cited 'Fairman v UKCC [2014] UKUT 479 (LC)'; tribunal could not find this case and considered it may be inauthentic.
Fabricated (Case Law)

Respondent cited 'Ellis v APL Co Ltd [2011] EWCA Civ 1088'; tribunal was unable to find this authority and suggested it may be AI-generated.
Misrepresented (Case Law)

Respondent cited 'Anchor Trust v Wandsworth LBC [2007] EWCA Civ 1051' but tribunal found the citation related to Mohanaei v Mohanaei and the summary given by Respondent was inaccurate.
Misrepresented (Case Law)

Respondent cited 'Willmott Dixon Housing Ltd v Secretary of State [2009] EWCA Civ 1044' but tribunal found that the reference corresponds to Pablo Star Ltd v Emirates Integrated Telecommunications Co PJSC [2009] EWCA Civ 1044 and is not authority for the asserted proposition.
Misrepresented (Case Law)

Respondent cited 'Osborn v Parole Board [2013] UKSC 61 [2] [68]-[72]'; tribunal noted the full judgment concerns parole hearings and that the passages cited did not appear relevant to the Respondent's argument.
Misrepresented (Case Law)

Respondent cited 'Sheffield City Council v Oliver [2017] UKUT 349 (LC)'; tribunal suggested the Respondent may have intended Oliver v Sheffield City Council [2017] EWCA Civ 225 and that the UKUT citation/summary was inaccurate.
Misrepresented (Case Law)

Respondent cited 'Waaler v London Borough of Hounslow [2017] EWCA Civ 45' but tribunal stated the Respondent's summary of the case was inaccurate (misstated the legal test).
Misrepresented (Case Law)

Respondent cited 'Garside v RFYC Ltd [2011] UKUT 367'; tribunal noted mixed judicial consideration and did not accept the Respondent's claimed authoritative proposition.
Fabricated (Case Law)

Respondent cited 'Lambeth LBC v O’Kane [2013] UKUT 0538 (LC)'; tribunal could not locate this citation and flagged potential inauthenticity.
Misrepresented (Case Law)

Respondent cited 'Forcelux Ltd v Sweetman [2001] EWCA Civ 1217' but tribunal found that the citation corresponds to Director General of Fair Trading v Proprietary Association of Great Britain (Costs) and that the Respondent's summary did not match the true authority.

Which AI tool

an unnamed/unconfirmed AI tool. 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

Not specified in source record.

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.

Check a brief before you file it → · See our live false-verify rate

Source: https://www.damiencharlotin.com/documents/1104/Napier_House_LU1_1DU_Appeal_UK_7_July_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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