There is a warning that tens of thousands of people could face penalties after HMRC’s online filing system failed to reflect the 2024 Budget changes to capital gains tax (CGT). Rates increased from 10% to 18% for basic-rate taxpayers and from 20% to 24% for higher-rate taxpayers on most assets from October 30, 2024. However, HMRC’s system was locked before the update, causing miscalculations for those filing digitally without advisers. Mistakes could lead to underpaid tax, 8% interest charges, and fines up to 30%.

The issue arises as HMRC prepares a wider digital overhaul, including mandatory third-party filing from 2026.  I continue to raise my concerns about their system readiness and my lack of confidence in tax administration.