Law360, London (May 22, 2026, 7:51 PM BST) -- Pinsent Masons LLP has referred itself to the Solicitors Regulation Authority after admitting that one of its junior lawyers used artificial intelligence to generate made-up law in letters sent to court, as a London judge said Friday he would not consider initiating contempt proceedings.

Insolvency and Companies Court Judge Mark Mullen said the regulator is best placed to investigate what he considered to be a junior associate's "remarkable" production of "plainly wrong or, at the very least, extremely misleading" court letters.

The junior associate, who was identified only as LA, used Pinsent Masons' AI in March to draft a letter in connection with a block transfer application — a process for transferring appointments from one insolvency practitioner to another.

Judge Mullen said that it appeared the lawyer had not checked the AI's responses using authoritative online resources or books, despite the AI itself expressly warning to do so because it was "not fully confident" with its answers.

The court queried the first letter which offered a quotation from a statute the judge had never heard of. Solicitors supervising the matter did not check the letter, Judge Mullen said, but "LA does not seem to have alerted their supervisors that AI had been used at all" at that point. 

The lawyer again used AI to draft a response that was misleading, the judgment says, claiming that the first letter did not in fact directly quote statute law. 

The lawyer's managing associate should have more thoroughly investigated the reasons for the first letter's misstatement, but Judge Mullen said he was satisfied they did not intend to mislead the court. The manager told the court that they were "mortified" that inaccurate statements of the law were sent out in the firm's name.

Observing the chat between the lawyer and the AI, Judge Mullen noted that "the hallucinations began almost immediately." When discussing legislation, the AI referenced an Insolvency rule from 2016 that had nothing to do with block transfer applications, the judge said.

The AI's citations of various pieces of legislation were incorrect multiple times, Pinsent Masons' evidence to the court shows.

Judge Mullen found the evidence "very troubling," stressing that the AI producing fake evidence could have been avoided had the junior lawyer "simply checked any of the statutory provisions that the AI referred to." It seemed the junior lawyer relied almost exclusively on AI to get answers, he added.

The letter may well have resulted from "a serious lack of care and of judgment on the part of LA rather than a want of honesty," the judgment states. Judge Mullen noted that at one point the lawyer told the AI "we don't want to mislead."

"The administration of justice cannot properly function if the court cannot trust its officers (in the case of solicitors) or those with an overriding duty to the court (such as barristers) to protect it from being misled," Judge Mullen wrote.

Judge Mullen added that he had no doubt that Pinsent Masons was taking the matter very seriously and was seeking to address the risks identified.

A spokesperson for Pinsent Masons said, "We have apologized unreservedly to the court and are taking steps to strengthen our processes and oversight to ensure this does not happen again. As the matter has been before the court, it would not be appropriate to comment further."

Pinsent Masons was represented by Paul Mitchell KC of 4 New Square Chambers, instructed by Clyde & Co. LLP.

The case is Anthony Cork and another v. Mark Smith, case number CR-2026-002244, in the High Court of Justice of England and Wales.

--Editing by Hazel Vidler. 

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