What is a reasonable excuse for missing a tax deadline?

Missing a tax deadline can result in penalties from HMRC, but a taxpayer may be able to appeal if they have a genuine reasonable excuse. Whether an excuse is accepted depends on the individual facts and whether the taxpayer took action to put things right without unnecessary delay.

HMRC does not provide a complete list of acceptable excuses, as each case is considered on its own facts. However, examples that may qualify include serious illness, bereavement, unexpected events outside the taxpayer’s control, or problems with HMRC’s systems that prevented a return or payment being made on time.

Other situations may also be accepted where the taxpayer can demonstrate that circumstances prevented them from meeting the deadline and that they took action to put matters right without unreasonable delay once those circumstances ended. For example, a taxpayer may have experienced an unexpected failure of computer equipment or lost essential records due to circumstances beyond their control.

A reasonable excuse will generally not include situations such as forgetting a deadline, relying on another person who failed to complete the task, or not having enough money to pay a tax bill unless the financial difficulty was caused by an exceptional circumstance.

If HMRC accepts that there was a reasonable excuse, the penalty may be cancelled. Taxpayers should appeal promptly, normally within 30 days of the date on the penalty notice, and explain what happened, when it occurred and why it prevented them from meeting their obligation.

Keeping good records and contacting HMRC as soon as a problem arises can help demonstrate that reasonable steps were taken to meet tax responsibilities.

Source:HM Revenue & Customs | 23-08-2026
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Aitch
I'm Aitch, the Founder and CEO of CIGMA Accounting Ltd. As a Chartered Management Accountant and as a CIMA member, I've spent more than 16 years helping businesses, entrepreneurs, landlords, and individuals with tax planning, accounting, and HMRC compliance. As a chartered accountant in London, I'm passionate about making complex tax matters easier to understand and helping clients make confident financial decisions. Over the years, I've advised start-ups, SMEs, established companies, and high-net-worth individuals across a wide range of tax and accounting matters. My expertise includes Corporation Tax, Self-Assessment, Capital Gains Tax, Inheritance Tax planning, R&D tax relief, capital allowances, international tax, and resolving complex HMRC compliance issues. Whether clients need a business accountant, tax accountant, or strategic tax advisor, my focus is always on delivering practical advice that creates long-term value. One of my specialist areas is Making Tax Digital (MTD). I've worked extensively with businesses preparing HMRC's digital reporting requirements, helping them move to cloud accounting, improve financial processes, and adopt technology that makes compliance more efficient. I regularly speak at Making Tax Digital roadshows, industry events, and educational sessions in collaboration with Zoho Books, sharing practical insights into digital accounting, tax legislation, and the future of the profession. Many business owners looking for the best accounting firm in London are not simply searching for an accountant they're looking for trusted advice, responsive support, and long-term value. That's the approach I've taken in building CIGMA Accounting. My team and I work closely with businesses across London and the UK, providing accounting services, tax advisory, bookkeeping, payroll, VAT, company accounts, and strategic tax planning tailored to each client's goals. Through this website, I share practical guidance on UK taxation, Making Tax Digital, HMRC updates, Corporation Tax, Self-Assessment, and business finance. My aim is to provide reliable, straightforward information that helps business owners understand changing regulations, reduce compliance risks, and make informed financial decisions with confidence.