In September 2025, HMRC published Guidelines for Compliance (GfC) 13, setting out the steps taxpayers should take to ensure that tax returns and other documents are correct and complete. Although there is no requirement to follow the guidelines, HMRC says that doing so will help taxpayers to reduce the risk of a compliance check and avoid unexpected tax liabilities. GfC13 is considered in detail in an earlier article.  

HMRC has now written to wealthy taxpayers who it believes may benefit from following GfC13 and, in particular, the guidance on legal interpretation. In GfC13, HMRC says that where the taxpayer has relied on a particular interpretation of the law when submitting a tax return or other document to HMRC, they should: 

• ensure that it is “based on all relevant facts”; and
• “honestly believe” that, where there is more than one way in which the law could be interpreted in the circumstances, that the interpretation adopted is, “on balance, the most likely to be found correct if the courts and tribunals were to consider the issue”. 

The letter: 

• reminds the taxpayer of their responsibility to ensure that any tax returns and other documents they submit to HMRC are correct and complete, and that this remains their responsibility where they have an agent. The letter advises the taxpayer to consider sharing the letter with their agent if they have one;
• encourages them to let HMRC know when submitting a tax return or other document that contains an unresolved uncertainty;
• warns them that, if they submit a return or document that they “don’t reasonably believe to be correct”, HMRC will take this into account when it considers “charging penalties for inaccuracies”; and
• asks that they read GfC13 and complete an anonymous survey to help HMRC understand how GfC13 is being used. 

ICAEW understands that the letter has been sent to other taxpayer groups to help promote awareness of GfC13.