In September 2025, HMRC published “Guidelines for Compliance - GfC13” relevant to taxpayers who are:
• Uncertain of the correct interpretation of the law after making their best efforts to resolve the ambiguity.
• Considering / adopting a novel or improbable interpretation of the law, including after taking professional advice
The guidelines highlight the legal obligation of the taxpayer to provide a tax submission document that is correct (in both fact and law) and complete to the best of their knowledge. In adopting a filing position, HMRC make it clear that:
• A taxpayer has an obligation to make best efforts to resolve uncertainty on how the law should be applied before making tax filings.
• When seeking professional advice, this must be from a suitably qualified advisor.
• Where more than one interpretation of the law might be applied, the taxpayer must choose the interpretation that they believe is, on balance, most likely correct.
• The taxpayer is encouraged to disclose any novel interpretation / uncertainty to HMRC.
One to many postal campaign
Since the publication of the new guidelines, HMRC have written to wealthy taxpayers, asking them to review this guidance and complete an anonymous survey to collate feedback.
Implications for taxpayers
The issued guidelines do not represent a change in the law but HMRC will no doubt refer to them when making an assessment of taxpayer behaviour in relation to penalties. Careful reference to the guidelines should help the taxpayer (in a self-assessment system) reduce the risks of compliance checks and unexpected tax liabilities.
The publication of these guidelines forms a significant part of HMRC’s broader efforts to enhance compliance standards targeted at both taxpayers and also advisers who from May 2026 will be subject to mandatory government registration.
