Simple assessment letters - sometimes called a PA302 – are tax bills issued to those taxpayers not in self assessment who did not pay enough tax in the previous year and where the shortfall could not be collected through the pay as you earn system. Tax collected under simple assessment commonly includes the state pension and bank and building society interest.

A record 1.8 million taxpayers are expected to receive simple assessment letters in 2025/26, up from the 675,000 letters HMRC sent just five years ago. The uplift is driven by a number of factors including the freezing of the income tax personal allowance at £12,570, the impact of the state pension triple lock and increases in interest rates since the COVID-19 pandemic.

Some taxpayers and pensioners have already received their simple assessment letters, while a second tranche of correspondence related to bank and building society interest data will be sent between October and December 2026.

The due date for paying a simple assessment tax bill for 2025/26 is 31 January 2027, unless a different date is shown on the letter.

ICAEW has encouraged taxpayers receiving a simple assessment letter to call or write to HMRC if they:

• believe that the letter contains an error. Taxpayers should check the figures used in the simple assessment calculation against their records, and contact HMRC to ensure that any figures estimated based on historic amounts, such as via employer benefits, pension contributions and donations under gift aid, are accurate;
• think it should be withdrawn. Where a simple assessment letter is sent to a taxpayer who is within self assessment the taxpayer, or their agent, should contact HMRC and ask for the simple assessment to be withdrawn;
• have any queries. However, before contacting HMRC, ICAEW advised taxpayers to check guidance online.

Katherine Ford, ICAEW Tax Technical Manager, said: “With a large uptick in the number of taxpayers receiving simple assessment letters, we would urge anyone who receives a letter to check it carefully and to contact HMRC if they have queries, believe the letter contains an error, or think it should be withdrawn.”

ENDS

Notes to editors:

Taxpayers may wish to read HMRC’s guidance for pensioners; on checking a simple assessment tax bill; and on calculating tax on bank and building society interest.