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Company case

Primus Solicitors: 18 court citations that did not exist, taken from a client’s AI research

A solicitor at a small law firm filed a statement with 45 case citations. Eighteen of the cases did not exist. His client had produced the research with public AI tools, and nobody at the firm checked it. The court referred him to his regulator.

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Outcome Went wrong

Something failed in work where AI was used, and there is a public record of it.

In the guide Micro and small businesses

At a glance

Company
Primus SolicitorsLaw firm
Size
Micro and small (1–49 employees) Primus Solicitors Limited reported an average of 10 employees in its accounts for the year to 30 April 2025.
Industry
Professional services
Where and when
United Kingdom (England and Wales). April – June 2025.
Who produced the figures
Court or tribunal recordThe facts and quotations come from the High Court’s published judgment. The headcount comes from the firm’s accounts filed at Companies House.

What happened

The firm acted for a client who was claiming £89.4 million from a bank. In spring 2025 the client and his solicitor each filed a witness statement in support of an application. Both statements cited case law.

A judge noticed that many of the cases looked wrong and had them checked. She then sent the matter to a panel of two senior judges, who heard it together with a second case of the same kind.

The numbers

  • 45 citations were put before the court.
  • 18 of the cases did not exist. Many of the others did not contain the quotes attributed to them, or did not support the point they were cited for.
  • One of the fake decisions was attributed to the very judge who was hearing the application.
  • 10 employees on average at the firm in the year to April 2025, and 4 the year before.

What the court found

  • The client did the research with AI. He told the court that the citations were “generated using publicly available artificial intelligence tools, legal search engines and online sources”. He said he had trusted them completely.
  • The solicitor passed it on unchecked. He said he had relied on his client’s research “without independently verifying the authorities”. The court called this “a lamentable failure to comply with the basic requirement to check the accuracy of material that is put before the court”.
  • It was not deliberate. The court accepted that the solicitor did not know the citations were fake.
  • He owned up. He apologised, reported himself to the Solicitors Regulation Authority and stepped back from court work. The court made its own referral to the regulator and did not start contempt proceedings.

What the court said about AI tools

The judges wrote that freely available tools such as ChatGPT “are not capable of conducting reliable legal research”. Their answers can be confident, plausible and untrue.

They also said that whoever uses such a tool for research has a professional duty to check the result against real sources before using it. This applies equally to someone who relies on another person’s work.

And they addressed managers directly. People who lead legal practices must now take “practical and effective measures” so that everyone understands these duties. Publishing guidance, the court said, is not enough by itself.

The second case in the same judgment

In the other case, a law centre and a barrister filed papers citing five cases that did not exist. A lower court had ordered each of them to pay £2,000 in wasted costs. The barrister denied using AI, and the court did not decide where the fake cases came from. When the other side first pointed the cases out, the law centre’s reply called them “cosmetic errors”.

The judgment also shows how the check went missing. The barrister was a pupil, still in training. She told the court that “none of her written work was checked” during a busy part of her training. The law centre is a charity with “minimal public funding” and a “very significant volume of cases”. It said it had never been its practice to check counsel’s citations. Each side relied on the other, and nobody checked.

What the case shows

  • The risk can come in from outside. Here it was the client who used AI. The firm needed a check on what it received, as well as on what it wrote.
  • A ten-person firm is held to the same standard as a large one.
  • A check needs a named owner. In the second case, the law centre relied on the barrister and nobody checked the barrister’s work.
  • The check is simple. Look each source up in a real database before it goes out.

What this says about the practices

Practices the company applied

Practices that were missing

Sources

  1. R (Ayinde) v London Borough of Haringey and Al-Haroun v Qatar National Bank [2025] EWHC 1383 (Admin). Judgment of 6 June 2025. High Court of England and Wales, Divisional Court. judiciary.uk
  2. Companies House. Primus Solicitors Limited (company number 10999760). Filing history, accounts for the year to 30 April 2025. find-and-update.company-information.service.gov.uk