ICAEW is urging taxpayers to take action ahead of the 31 January 2026 deadline for submitting their income tax self assessment (ITSA) tax return for 2024/25 online and for paying any tax due.

Stephen Relf, ICAEW Technical Manager, Tax said:

“Taxpayers must take the appropriate action before 31 January 2026, from submitting their tax return and paying their tax to contacting HMRC to have the requirement to submit a return withdrawn. Failure to act in time may mean they have to pay interest or penalties - costs that could otherwise have been avoided.

“If the taxpayer is struggling to raise the funds to pay their tax bill, they should consider contacting HMRC by 31 January 2026 to agree a payment plan, remembering that interest will continue to accrue on tax paid late.”

Submitting the tax return

Taxpayers who have registered for ITSA should have received a notice to file a tax return for 2024/25 from HMRC. The easiest way for the taxpayer to check if HMRC is expecting a return from them is by logging into their HMRC account or by using the HMRC app.

Before submitting their return, the taxpayer should check if a return is required as changes have been made to the criteria for 2024/25. This can be done by using HMRC’s online tool.

If a return is required, the taxpayer should submit their return by 31 January 2026 to avoid a £100 late filing penalty. If they are waiting on information to complete their return, they should consider using provisional figures.

If the taxpayer believes that a return is not required, they should contact HMRC before 31 January 2026 to have the notice withdrawn. If they fail to submit a return after receiving a notice to file, they could incur a penalty.

Paying the tax

Any tax due for 2024/25 must be paid by 31 January 2026 to avoid interest. The rate of interest charged by HMRC on underpaid tax is currently 7.75%. Any tax still outstanding after 30 days will attract a late payment penalty of 5%. For guidance on how to make a payment, see HMRC's guidance.

The total amount due may include a payment on account (POA) of their tax liability for 2025/26 by 31 January 2026, calculated based on the taxpayer’s tax liability for the previous year. The taxpayer can apply to reduce their POA where they believe their tax liability for 2025/26 will be less than that for 2024/25.

Taxpayers who are unable to pay the full amount by the 31 January deadline should consider contacting HMRC to agree a time to pay arrangement. This will allow them to settle their tax liability in instalments over an agreed period of time. HMRC will still charge interest on any tax paid late, but penalties may be avoided if a payment plan is agreed in good time and is stuck to.

ENDS

Notes to editors: