HM Revenue and Customs (HMRC) is issuing a final warning to taxpayers across the UK: the deadline for settling Self Assessment tax bills is now just two weeks away. Missing the cut-off on 31 January 2026 could trigger a cascade of penalties, potentially reaching £1,600 or more.
The tax authority stresses that anyone required to file an online tax return must ensure their outstanding tax is paid in full by 11.59pm on 31 January. This follows the earlier deadline for paper returns, which passed on 31 October of the previous year.
Who Needs to File a Self Assessment Tax Return?
You are legally obligated to submit a Self Assessment return if you fall into specific categories for the last tax year. This includes being a self-employed sole trader who earned more than £1,000, or if you needed to pay Capital Gains Tax after selling an asset that increased in value. Partners in a business partnership must also file.
Furthermore, you may need to complete a return if your situation involves:
- Paying the High Income Child Benefit Charge without it being collected through your PAYE tax code.
- Receiving untaxed income from various sources, such as foreign earnings, tips and commissions, or rental income from property.
HMRC provides an online tool on GOV.UK to help individuals check if they need to send a return.
How to Pay and Avoid Steep Penalties
With the deadline fast approaching, HMRC is actively encouraging people to use its official app to make payments. Myrtle Lloyd, HMRC's Chief Customer Officer, highlighted its convenience: "Thousands have already paid via the HMRC app. It is quick and easy, and you can also see your payment history." The app can send helpful payment reminders.
While the app is a promoted option, a full range of payment methods is available on the GOV.UK website.
The Cost of Missing the Deadline
HMRC's penalty regime for late returns is strict and can quickly become expensive. It begins with an immediate £100 fixed penalty, even if you owe no tax.
If the return remains outstanding after three months, daily penalties of £10 per day are added, up to a maximum of £900. At the six-month mark, a further penalty of 5% of the tax owed or £300 (whichever is higher) is applied. An identical charge is added after 12 months.
Separately, late payment of the tax itself incurs penalties. If the tax bill is not paid by 31 January, a 5% charge on the unpaid amount is applied after 30 days. This penalty increases by another 5% at six months and again at 12 months late. Interest will also accrue on any outstanding tax from the due date.
What to Do If You Receive a Penalty
If HMRC issues a penalty for a late return or payment, you may have grounds to appeal. The key is demonstrating you had a 'reasonable excuse' for the delay.
Taxpayers typically have 30 days from the date the penalty notice is issued to contact HMRC and formally lodge an appeal. The process varies depending on your employment status and the type of tax involved, with full guidance available on the government's website.
The clear message from HMRC is that these financial penalties are entirely avoidable by filing and paying on time. With the 31 January deadline rapidly approaching, acting now is crucial to avoid unnecessary fines.
