{"schema_version":"0.10.0","id":"LR-2026-0535","record_version":1,"title":"Pinsent Masons reprimanded over AI hallucinations in UK court filings","verification":{"human_verified":false,"method":"automated_gate","auto_verified":true,"score":57.8,"score_breakdown":{"source_authority":12.1,"independent_corroboration":20.0,"implicated_party_confirmed":0.0,"citation_integrity":14.0,"specificity":0.0,"completeness":3.84,"unhedged_language":5.0},"checks":{"schema_valid":true,"every_field_cited":true,"quotes_verbatim":true,"source_fetched":true,"distinct_incident":true,"dates_plausible":true,"sources_agree":true,"source_describes_incident":true,"severe_backed_by_source":true,"record_integrity":true,"eligible":true,"about_this_case":true},"gate_version":"gate-2026-10-18.7","cross_check_model":null,"cross_check_agreement":null,"duplicate_of":null,"verified_by":null,"verified_at":"2026-11-01","extraction_run_id":null,"evidence_level":{"level":"preliminary","reason":"Publisher not yet named · subject to change","original_document":null,"reports_total":3,"reports_independent":0,"reports_derivative":0,"developing":false,"disputed":false,"rules_version":"evidence-2026-10-29.1","computed_at":"2026-11-01","history":[{"date":"2026-11-01","from_level":null,"to_level":"preliminary","reason":"Publisher not yet named · subject to change"}]},"sources_hash":"f77886bba7b47808d54cef8e63534e34eec38a571724a675547e5f47f2ed6756"},"system":{"model_name":null,"model_version":null,"developer":"unknown","harness":null,"tools_granted":[],"permissions_scope":null,"autonomy_level":"unknown","guardrails_present":[],"deployment_context":"unknown","tier":null,"lifecycle_stage":null,"integration_type":null,"intended_use":"legal research for insolvency court proceedings","safeguard_state":null,"production_intended":null},"event":{"date_occurred":null,"date_disclosed":"2026-05-26","incident_class":"hallucination","failure_class":null,"agent_involved":null,"secondary_failure_classes":[],"trigger":"unknown","duration":null,"detection_method":"unknown","summary":"A junior solicitor at Pinsent Masons used an AI tool for legal research on a block transfer insolvency application in a High Court proceeding. The firm's letter to the court cited an insolvency rule that did not exist, and a follow-up letter, also prepared with AI, repeated the problem. The judge described the first letter as likely an AI hallucination that had not been checked, after querying it with the firm. The judge found the material had not been checked properly, and that supervisors had not adequately reviewed the work, although they were unaware AI had been used. The firm apologised, self-referred to the Solicitors Regulation Authority, and met its former client's costs. The judge said contempt proceedings would be disproportionate.","tags":[],"date_detected":null,"near_miss":null,"root_cause":"oversight","root_cause_detail":"Supervisors did not adequately check the junior lawyer's AI-assisted research and drafts before they were sent to the court.","failure_class_detail":null,"responsible_party":null,"adversarial_actor":null,"input_provenance":null,"time_to_contain":null,"operations_paused":null,"remediation":null,"precursor_events":null,"primary_risk":"RK14","control_chain":[{"layer":"L3","party":"deployer","party_name":null,"control_id":"B1","outcome":"failed","reason":null,"quote":"Both Cottee and Poulson checked the first draft letter going out to the court which contained the mistakes and had confirmed within around two hours that it was fine.","source_index":1,"reviewed":false},{"layer":"L3","party":"deployer","party_name":null,"control_id":"I4","outcome":"missing","reason":null,"quote":"It also seems to me that, as part of the supervision of LA more generally, it should have been made clear to them, if it was not made clear, that they should check all references given by AI and be candid, when reporting the result of their research to their supervisors, as to whether AI had been used in that research and whether the content generated by the AI had been checked.","source_index":1,"reviewed":false}]},"impact":{"direct_loss_usd":null,"remediation_hours":null,"records_exposed":null,"third_parties_affected_count":null,"severity":"moderate","severity_because":"Moderate test: data or systems of others touched with a bounded scope (one insolvency application); the firm met its former client's costs, including costs of finding new lawyers.","harm_class":[],"affected_description":null,"protected_class_involved":null,"data_categories_exposed":[],"loss_range_usd":null,"reversibility":null,"downstream_exposure_count":null},"evidence":{"sources":[{"url":"https://www.legalcheek.com/2026/05/pinsent-masons-criticised-by-judge-over-junior-lawyers-ai-blunder/","publisher":"Legal Cheek","date":"2026-05-26","type":"press","title":"Pinsent Masons slammed by judge over junior lawyer’s AI blunder - Legal Cheek","archived_url":null,"attachment":"first_report"},{"url":"https://www.lawgazette.co.uk/news/pinsents-refers-itself-to-sra-over-ai-failures/5126895.article","publisher":"The Law Society Gazette","date":"2026-05-26","type":"press","title":"Pinsents refers itself to SRA over AI failures - The Law Society Gazette","archived_url":null},{"url":"https://www.resultsense.com/news/2026-05-27-pinsent-masons-ai-hallucination-court-reprimand/","publisher":"Resultsense","date":"2026-05-27","type":"press","title":"Pinsent Masons reprimanded for AI hallucination in UK court - Resultsense","archived_url":null}],"per_field_confidence":{"event.incident_class":"C","system.intended_use":"C","event.root_cause":"C","event.root_cause_detail":"C","context.industry":"C","impact.severity":"D","impact.severity_because":"D","event.primary_risk":"D","event.control_chain":"C","event.summary":"C","system.autonomy_level":"D","system.deployment_context":"D","event.trigger":"D","event.detection_method":"D","context.country":"D","system.developer":"D","event.date_disclosed":"D","context.denominator_available":"D"},"field_citations":{"event.incident_class":[{"source_index":0,"quote":"Pinsent Masons has been criticised by a High Court judge after AI-hallucinated legal authorities, produced during a junior lawyer’s research, were relied upon during insolvency proceedings."}],"system.intended_use":[{"source_index":0,"quote":"According to the judgment, the firm cited an insolvency rule that did not exist, which arose from a junior solicitor using AI tools to conduct legal research for the proceedings."}],"event.root_cause":[{"source_index":0,"quote":"The judge also criticised the failure of supervisors (despite not being aware of the use of AI) to properly check the work done and that there appeared to be a “failure to supervise [the junior lawyer] adequately”."}],"event.root_cause_detail":[{"source_index":0,"quote":"The judge also criticised the failure of supervisors (despite not being aware of the use of AI) to properly check the work done and that there appeared to be a “failure to supervise [the junior lawyer] adequately”."}],"context.industry":[{"source_index":0,"quote":"Pinsent Masons has been criticised by a High Court judge after AI-hallucinated legal authorities, produced during a junior lawyer’s research, were relied upon during insolvency proceedings."}],"impact.severity":[{"source_index":1,"quote":"The firm has also met its former client’s costs, including the costs of finding new lawyers."}],"impact.severity_because":[{"source_index":1,"quote":"The firm has also met its former client’s costs, including the costs of finding new lawyers."}],"event.control_chain":[{"source_index":1,"quote":"Both Cottee and Poulson checked the first draft letter going out to the court which contained the mistakes and had confirmed within around two hours that it was fine."},{"source_index":1,"quote":"It also seems to me that, as part of the supervision of LA more generally, it should have been made clear to them, if it was not made clear, that they should check all references given by AI and be candid, when reporting the result of their research to their supervisors, as to whether AI had been used in that research and whether the content generated by the AI had been checked."}],"event.summary":[{"source_index":0,"quote":"Pinsent Masons has been criticised by a High Court judge after AI-hallucinated legal authorities, produced during a junior lawyer’s research, were relied upon during insolvency proceedings."},{"source_index":0,"quote":"According to the judgment, the firm cited an insolvency rule that did not exist, which arose from a junior solicitor using AI tools to conduct legal research for the proceedings."},{"source_index":0,"quote":"As I say, it struck me as likely to be an AI hallucination, which had not been checked."},{"source_index":0,"quote":"The judge also criticised the failure of supervisors (despite not being aware of the use of AI) to properly check the work done and that there appeared to be a “failure to supervise [the junior lawyer] adequately”."},{"source_index":1,"quote":"The judge said it would be disproportionate to consider contempt proceedings but added that there was, at the very least, a prima facie case of a breach of the duty not to mislead the court and the duty not to waste court time."},{"source_index":1,"quote":"Pinsent Masons has apologised and referred itself to the Solicitors Regulation Authority, which will also investigate whether any of the lawyers involved have breached the code of conduct."},{"source_index":1,"quote":"The firm has also met its former client’s costs, including the costs of finding new lawyers."}]},"notes_on_gaps":"The sources do not name the AI model, its developer, the harness, the tools granted, or the permissions. No occurrence date is stated; the 14th April letter is the only dated event and the year is not stated in the quote. date_disclosed uses the 2026-05-26 press date, not a judgment date. Detection is attributed to the judge, who is a third party to the firm, so detection_method is judged as human_review. Deployment_context production is inferred from use on live court filings and the internal pilot. Severity moderate is a judgement: the court and a former client were touched in one bounded application. No dollar figures, record counts or third-party counts are stated. Responsible party deployer is a judgement from the firm's own apology. controls_added for the remediation is a judgement based on the firm's stated oversight steps; the source names no specific control. Adversarial actor is omitted because the sources state no intent to mislead by the supervisors and no external actor. Resultsense claims about partner pay and other cases are excluded as unsupported by the other sources. [case created by the backfill: read by claude-haiku-5-5, backfill-2026-11-01.2, 2026-11-01; not yet reviewed] [2026-11-01: evidence level set: Preliminary (Publisher not yet named · subject to change)]"},"context":{"industry":"legal services","org_size_band":null,"country":"unknown","denominator_available":false,"denominator":null,"related_incident_ids":[],"systemic_exposure":null,"shared_model_id":null,"upstream_incident_id":null,"incident_evidence":null,"regulatory":null,"coverage":null},"narrative":{"steps":[{"step":"doing","text":"The firm was instructed to prepare a block transfer insolvency application for a court matter.","quote":"The court heard that Pinsent Masons had been instructed to prepare a block transfer application for an insolvency matter.","source_index":1,"grade":"C"},{"step":"went_wrong","text":"A junior solicitor used AI tools for legal research, and the firm cited an insolvency rule that did not exist.","quote":"According to the judgment, the firm cited an insolvency rule that did not exist, which arose from a junior solicitor using AI tools to conduct legal research for the proceedings.","source_index":0,"grade":"C"}],"model":"claude-haiku-5-5","prompt_version":"backfill-2026-11-01.2","extracted_at":"2026-11-01","source_urls":["https://www.legalcheek.com/2026/05/pinsent-masons-criticised-by-judge-over-junior-lawyers-ai-blunder/","https://www.lawgazette.co.uk/news/pinsents-refers-itself-to-sra-over-ai-failures/5126895.article","https://www.resultsense.com/news/2026-05-27-pinsent-masons-ai-hallucination-court-reprimand/"]},"analysis":{"sections":{"timeline":[{"text":"Pinsent Masons was instructed to prepare a block transfer application for an insolvency matter.","quote":"The court heard that Pinsent Masons had been instructed to prepare a block transfer application for an insolvency matter.","source_index":1,"when":null},{"text":"The firm has since self-referred to the SRA.","quote":"The firm has since self-referred to the Solicitors Regulatory Authority (SRA).","source_index":0,"when":null}]},"model":"claude-haiku-5-5","prompt_version":"backfill-2026-11-01.2","extracted_at":"2026-11-01","source_urls":["https://www.legalcheek.com/2026/05/pinsent-masons-criticised-by-judge-over-junior-lawyers-ai-blunder/","https://www.lawgazette.co.uk/news/pinsents-refers-itself-to-sra-over-ai-failures/5126895.article","https://www.resultsense.com/news/2026-05-27-pinsent-masons-ai-hallucination-court-reprimand/"]}}