Judge criticises use of fabricated AI-generated cases in HMRC appeal

The case involved an appellant who cited authorities that could not be traced by the tribunal or HMRC. During the proceedings, it became apparent that several of the referenced cases did not exist and appeared to have been generated using AI tools. The judge expressed concern that material had been submitted without proper verification, noting that the tribunal process depends on parties accurately presenting legal authorities and supporting evidence. While AI tools are increasingly used in professional and advisory work, the judgment underlined that responsibility for checking accuracy remains with the individual relying on the material.

The incident reflects a wider issue emerging across legal and professional services, where generative AI systems can produce convincing but entirely fictional citations or references. In a tax context, this creates particular risks where submissions involve technical legislation, tribunal authorities or procedural arguments. For advisers and businesses using AI tools in tax work, the practical message is straightforward: outputs must be checked carefully before being relied upon or submitted formally. The tribunal’s criticism makes clear that inaccurate or fabricated authorities will not be treated lightly, even where AI was involved in producing them.