HMRC late payment penalties are now affecting 1.1 million UK taxpayers who missed the 31st January self-assessment deadline. If you haven’t filed yet, you could face increasing fines, interest charges, and even HMRC investigations. While the late payment interest rate has slightly decreased, the penalties remain severe. Here’s what you need to know and how to avoid extra charges.
HMRC Late Payment Penalties Adjusted – But Is It Enough?
HMRC late payment interest is currently 7% (Base Rate + 2.5%), reflecting the latest Bank of England base rate as of February 2026. Interest is charged daily on overdue amounts until fully paid. While this might seem like a relief, tax experts argue that it’s not as beneficial as it sounds. Tax expert Andy Wood of Tax Natives highlights a key issue:
“While this drop in HMRC’s late payment interest offers some relief, it’s hardly significant in the grand scheme of things. The real issue is that taxpayers still pay double the interest on late payments compared to what HMRC pays them in refunds. That’s a fundamental imbalance.”
HMRC Late Payment Interest vs. Refunds:
Late Payment Interest: 7% (Base Rate + 2.5%)
Interest on overpaid tax is 3.5% (Base Rate – 1%, minimum 0.5%), as per HMRC guidelines. This ensures a lower return than the interest charged on late payments
This means that if you owe HMRC money, you’re charged nearly double the interest rate than what they would pay you for an overpayment.
How Much Could You Be Fined?
If you haven’t filed your self-assessment tax return, here’s what to expect:
✔ Up to 3 months late – £100 fixed penalty
✔ 3–6 months late – 5% of tax due or £300, whichever is higher
✔ 6–12 months late – Additional 5% of tax due or £300, possible further penalties for deliberate late filing
✔ Over 12 months – Penalties increase further, especially if HMRC considers it deliberate.
Example Scenario:
If you miss the 31 January self-assessment filing deadline, HMRC may charge the £100 initial penalty, followed by additional 5% of the tax due or £300 after 3–6 months, potentially escalating to further penalties after 12 months.
For high earners (£150,000+), the penalties can be even more severe, with stricter scrutiny from HMRC.
Late Payments May Trigger HMRC Investigations
Beyond financial penalties, there’s another major risk HMRC investigations.
“The longer a tax bill remains unpaid, the greater the risk of HMRC scrutiny. Late payments can flag taxpayers for further investigation, which can be time-consuming and costly,” warns Andy Wood.
HMRC Red Flags for Late Taxpayers:
✔ Consistently late filings or payments
✔ Significant underpayment of tax
✔ Unusual financial transactions or deductions
✔ Large cash deposits or undeclared overseas income
If HMRC selects you for an enquiry or compliance check, you may be required to provide detailed records, bank statements, and justifications for expenses, which could lead to further penalties.
The End of the Tax Year- Act Now!
With April marking the end of the current tax year, taxpayers are urged to settle outstanding payments and take advantage of financial allowances before the deadline.
Key Allowances to Use Before April 5:
✔ £20,000 ISA allowance – maximise your tax-free savings for 2025/26
✔ £60,000 annual pension contribution limit – reduce taxable income while saving for retirement
✔ Carry-forward tax relief – Use any unused pension allowances from the past three years
How to Avoid Extra HMRC Fines & Charges
1. Pay Your Outstanding Tax ASAP
Even if you can’t pay in full, making a partial payment reduces interest and penalties.
2. Contact HMRC for a Payment Plan
If you’re struggling to pay, you may qualify for HMRC’s “Time to Pay” arrangement, allowing you to spread payments over months.
3. File Your Return Immediately
Even if you can’t pay yet, submit your return ASAP to avoid escalating fines.
4. Seek Professional Help
A qualified accountant or tax adviser can help you negotiate with HMRC, claim tax reliefs, and structure payments efficiently.
Final Warning: Don’t Delay Further!
If you’re one of the 1.1 million UK taxpayers who missed the January 31 deadline, act now to avoid extra penalties, mounting interest, and potential HMRC scrutiny.
Need Help Managing Your Tax Liabilities?
Professional accountants can assist with late filings, minimise penalties, and negotiate Time to Pay arrangements with HMRC. Acting promptly reduces financial and compliance risks.
