HMRC reasonable excuse rules matter if you miss a tax deadline and want to challenge a penalty. Many taxpayers assume their reason will qualify. However, HMRC sets the bar high. Understanding what counts, what does not, and how HMRC views each case can save you time, money, and frustration.
Missing a filing or payment deadline can happen to anyone. Life gets in the way. Problems appear when HMRC issues a penalty, and you believe you had a fair reason. That is where the idea of a HMRC reasonable excuse comes in. But the rules do not work on sympathy. They work on evidence, circumstances, and your behaviour.
In this blog, I outline what a reasonable excuse is, how HMRC decides, and the common pitfalls to avoid.
What Is a HMRC Reasonable Excuse?
There is no legal definition of a reasonable excuse. Parliament has never written one into tax law. That means every case depends on context.
HMRC looks at what a sensible, responsible person would have done. They compare your situation, abilities, and circumstances with that standard. If they believe a reasonable person could still have met the deadline, they reject the excuse.
What counts as reasonable for one person may not apply to another. Personal ability, mental health, disability, or sudden events can all change the picture. HMRC says that a HMRC reasonable excuse must show that something serious prevented compliance, not that something was inconvenient or difficult.
Examples HMRC Accept
HMRC publishes guidance that lists situations likely to qualify. These examples help, but they are not automatic guarantees. You still need evidence.
Below are common reasons HMRC may accept.
Bereavement
If a partner or close relative dies shortly before a deadline, HMRC usually accepts this. They expect people to deal with grief, funerals, and family disruption. Evidence is simple: a death certificate or funeral communication is normally enough.
Unexpected Hospital Stays
An unplanned hospital stay that stops you managing your tax affairs can qualify. HMRC will ask whether you could have delegated the work and how long you were incapacitated.
Serious Illness
A serious or life-threatening illness can form a strong reasonable excuse. Again, they want to see timing, severity, and impact.
Technical Problems
If your computer or software fails while preparing an online return, HMRC may accept this. You must show that the issue was unexpected and outside your control.
HMRC System Failures
When HMRC online services fail or suffer errors, that can count. HMRC keeps internal logs, so this is normally straightforward.
Natural Events
Floods, fires, thefts, or similar events that prevent access to your records or equipment can qualify.
Postal Delays Outside Your Control
Unexpected postal strikes or delays outside your control may be accepted. You must show you posted the return in good time.
Disability or Mental Illness
Where a taxpayer has a disability or mental health condition that affects their ability to meet a deadline, HMRC will consider this. They look at overall impact and timing rather than diagnosis alone.
Misunderstanding Legal Obligations
A misunderstanding of your obligations can sometimes qualify if the rules are unclear. However, claiming you “did not know” rarely succeeds on its own.
Relying on Someone Else
If you relied on an accountant or another person and they failed to act, HMRC may consider this. They assess whether you took reasonable care in choosing and managing that person.
What HMRC Will Not Accept
Some excuses fail instantly. HMRC lists several examples they will not accept under any circumstances.
Insufficient Funds
If your payment bounced because there was not enough money in your account, HMRC rejects it. Poor financial planning is not a reasonable excuse.
Problems Using HMRC Systems
Saying the HMRC system is “too difficult” never succeeds. HMRC expects you to seek help or use an agent.
No Reminder Received
HMRC has no duty to send reminders. Missing one does not give you grounds for appeal.
Simple Mistakes
Errors on the return are not grounds for a penalty appeal. HMRC expects corrections to be made through amendments.
These examples show that a HMRC reasonable excuse must involve something genuinely serious and unavoidable, not inconvenience.
Fixing the Problem Quickly
Even when HMRC accepts your reason, they expect prompt action. That means filing the return or making the payment as soon as you reasonably can. Delay weakens your case and risks refusal.
Evidence is essential. HMRC rarely accept excuses without documents. Provide dates, reports, receipts, hospital notes, screenshots, postal records, or photographs. A clear timeline helps HMRC see that the reason directly caused the delay.
How to Strengthen Your Appeal
If you appeal a penalty based on a HMRC reasonable excuse, follow this structure:
1. Explain What Happened
Keep it factual and brief.
2. Show Why It Prevented Compliance
Tie the incident to the deadline.
3. Show What You Did Next
Action is key. HMRC want to see effort.
4. Provide Evidence
Attach everything relevant.
5. Show It Was Unavoidable
Demonstrate that you acted as a reasonable person would.
Plan It, Do It, & Profit!
A HMRC reasonable excuse is not a free pass. It must be genuine, serious, and clearly linked to the missed deadline. Understanding HMRC’s expectations helps you avoid unnecessary penalties and strengthens any appeal you may need to make.
If you want expert help dealing with penalties, deadlines, or tax planning, book a call today. I can guide you through the process and help you stay compliant while keeping stress levels low.
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