Marc Gunnarsson was asked to provide supporting arguments to an appeal at the Upper Tribunal after HMRC rejected two claims for self-employment income support scheme (SEISS) totalling £12,918 during the pandemic, but he blundered by using an AI chatbot to try to substantiate his argument.

The Upper Tribunal scolded Gunnarsson, who represented himself, for including fictitious cases in his skeleton argument, which was only provided to the court one day before the hearing date.

The skeleton contained reference to three previous decisions ‘purportedly made by the FTT which were said to support his interpretation of the legislation’, Judge Rupert Jones noted.

The phantom cases were Patel v HMRC [2023], Ali v HMRC [2022] and Kamran v HMRC [2023], claiming reliance on an accountant’s advice in one instance, while two pertained to SEISS, including the clarity of HMRC’s guidance and eligibility.

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