Pinsent Masons reprimanded by UK court after AI legal citation error

In short: A UK High Court judge reprimanded Pinsent Masons after a lawyer used AI and submitted an inaccurate legal reference to the court.

What happened

A judge in London’s High Court has admonished Pinsent Masons, a major UK law firm, after the court was misled by incorrect legal wording in a routine insolvency case.

Judge Mark Mullen said the court was misled twice because the firm inaccurately cited a statute, which is the text of a law. The judge only spotted the problem after questioning the reference. He said work pressure did not excuse a failure to check accuracy.

The mistaken submissions were made by a junior lawyer, described as “LA” in the judgment. A senior associate and a partner supervised the work. The supervisors said they did not know the junior lawyer had used AI.

The judgment included a transcript of the lawyer’s conversation with the AI tool, which the firm provided to the court. In that transcript, the AI tool warned that it was “not fully confident” it was reproducing the exact wording and told the lawyer to verify it before submitting anything.

Pinsent Masons apologised and said it had referred itself to the Solicitors Regulation Authority (SRA), the body that regulates solicitors in England and Wales. The firm said it is piloting a new AI program and adding safeguards.

Why it matters

AI tools can produce text that sounds confident but is wrong, a bit like a calculator that sometimes gives the right answer but sometimes invents a number. Judge Mullen warned that lawyers remain responsible for legal research and reasoning and cannot hand that job over to AI. For the public, it matters because courts rely on accurate information, and mistakes can affect cases, costs, and trust in the legal system.

Source: Financial Times