HMRC ‘flying blind’ on over 1.2m tax demands after failing to track error rates 

HMRC issued more than 1.2 million simple assessment tax calculations in 2024/25 but does not track how many taxpayers challenge them as incorrect, or how many are revised or cancelled. The gap has prompted criticism that the authority cannot measure the scale of errors in a system that automatically calculates tax for some people without requiring a self-assessment return.

The figures, obtained through a Freedom of Information request, show 1,254,201 PA302 assessments were sent that year. HMRC said it could not provide challenge or correction figures because it does not hold them in a readily available form, and its records do not reliably distinguish complaints about errors from other enquiries. Tax advisers estimate 1.8 million forms were sent in 2025/26; frozen income tax thresholds and rising state pensions are bringing more people into the tax system.