Missed the Self-Assessment Deadline?

Advice NI urges taxpayers who missed the Self-Assessment deadline to act quickly to avoid escalating penalties—even if no tax is owed.

An initial £100 fixed penalty applies immediately. After three months, daily penalties of £10 (up to £900) begin. After six months, an additional 5% of the tax due or £300 (whichever is greater) is charged, with the same penalty applying after 12 months. Unpaid tax also accrues interest.

Sinead Campbell, Head of Money, Debt & Quality at Advice NI, advises:

“Understanding your tax responsibilities is crucial to avoid penalties. You may need to file if you're newly self-employed and earned over £1,000, became a business partner, or received Child Benefit but must pay the High-Income Child Benefit Charge (for earnings over £50,000 in 2023/24). Even those earning below £1,000 might file voluntarily to protect National Insurance contributions.”

With side hustles on the rise—such as selling online, deliveries, or home-based beauty treatments—many people may unknowingly need to report earnings.

“If you earn less than £1,000 in a tax year, you don’t need to register or declare it. However, anything above this threshold must be reported to HMRC.”

Advice NI specialists are available to help.

“If you're unsure whether to file, have tax liabilities, or missed the deadline, contact our experts for support,” Sinead adds.

📞 Freephone 0800 915 4604 to speak with our advice team or Business Debt Team.