Picture this: The dreaded brown HMRC envelope lands on your doormat. You open it to find a £100 late filing penalty notice for your Self-Assessment tax return. Your heart sinks. But you *had* a good reason—you were in the hospital for a week, or a close relative passed away, and tax was the last thing on your mind. If you've ever faced this, you're not just frustrated; you're looking for a solution.
That £100 penalty is just the start. If a return is three months late, daily penalties of £10 can be added, up to a maximum of £900. After six months, there's another penalty of 5% of the tax due or £300 (whichever is greater), with another identical penalty at 12 months (HMRC, 2025). This can spiral to over £1,600 even before interest. But HMRC has a formal system for this: the 'Reasonable Excuse' appeal. The problem? The line between a valid excuse that gets your penalty cancelled and a failed appeal is thin, highly specific, and often confusing for freelancers and the self-employed.
Key Takeaways
- Core Rule 1: A 'reasonable excuse' is an **unexpected or unusual event** that was genuinely outside your control (e.g., sudden serious illness, bereavement, major IT failure at the last minute).
- Core Rule 2: Excuses like 'I was too busy,' 'I forgot the deadline,' 'I couldn't afford the tax,' or 'my accountant was slow' are **almost always rejected** by HMRC.
- Key Data Point: HMRC's own internal guidance confirms that 'pressure of work' is not a valid excuse, but 'an unexpected, serious or life-threatening illness' is (HMRC Compliance Handbook, 2025).
- When to Act: You typically have **30 days** from the date of the penalty notice to submit your appeal to HMRC.
- Disclaimer: This article provides informational guidance based on HMRC rules as of November 2025. It is not financial or tax advice. Penalty rules are complex and outcomes depend on specific facts—always consult a qualified accountant for your personal situation.
What *Is* a 'Reasonable Excuse' in HMRC's Eyes?
Let's explore what HMRC decision-makers are trained to look for. The core of a successful appeal rests on two principles: the event was **unexpected** and **outside your control**.
Think of a 'reasonable excuse' like appealing a parking ticket. 'The ticket machine was broken and wouldn't take payment' (out of your control) might work. 'I was late for a meeting and didn't have time to buy a ticket' (your own poor planning) will almost certainly fail. HMRC views tax deadlines in a similar light. They expect you to plan for foreseeable events, but they can make allowances for genuine, unforeseeable crises.
A successful appeal also depends on what you did *after* the event. HMRC expects you to have filed the return (or paid the tax) as soon as the excuse ended. For example, if you were in the hospital for two weeks, HMRC would expect you to have filed the return within a reasonable period *after* you were discharged—not six months later. The excuse is valid only for the period the event prevented you from acting.
Winning vs. Losing Appeals: A Scenario-Based Breakdown
The "reasonable excuse" test is subjective and depends heavily on facts and evidence. To make this practical, let's explore common scenarios I've seen discussed on forums like r/UKPersonalFinance and what the likely outcome would be. The difference is often in the *evidence* and *framing*.
| Your Scenario | Reasonable Excuse? | Why HMRC Will (or Won't) Accept It | Crucial Action & Evidence Needed |
|---|---|---|---|
| "I was in the hospital for 10 days with appendicitis right before the deadline." | Yes (Very Likely) | This is a classic example of an unexpected, serious medical event that was completely outside your control. | Appeal as soon as you are able. Provide evidence: a copy of your hospital admission or discharge letter showing the dates. |
| "A close relative (e.g., parent, partner) passed away in January." | Yes (Very Likely) | Bereavement of a close loved one is a well-established reasonable excuse. HMRC is generally understanding of this. | Appeal when you are able. You may need to provide the date of death and your relationship, but HMRC often handles this sensitively. |
| "I had severe flu and was bed-bound for the week of the deadline." | Maybe | This is a grey area. A simple cold will be rejected. Severe, debilitating flu *might* be accepted if it genuinely incapacitated you. | Evidence is key. A doctor's note covering the specific period is ideal. You must show you filed as soon as you recovered. |
| "I was suffering from severe depression and couldn't face my finances." | Maybe (Difficult) | Mental health is increasingly recognised, but "I was stressed" is not enough. You must demonstrate a diagnosed, serious condition. | This is a very difficult appeal to win without strong evidence from a GP or mental health professional explaining the *severity* and *dates* of the episode. |
| "My accountant got sick / went on holiday / made a mistake." | No (Almost Never) | HMRC's stance is clear: you are responsible for your own tax return, even if you delegate it. Your accountant's failure is not *your* reasonable excuse. | You cannot appeal this. Your only recourse is to pay the penalty and potentially make a formal complaint against your accountant. |
| "My laptop died with my records on it on January 30th." | Maybe (Difficult) | This depends on what you did next. If you can prove you took immediate steps (e.g., went to a repair shop) it might be considered. | You'll need evidence, like a dated repair invoice. "My internet was slow" or "my software crashed, and I left it" will be rejected. |
As you can see, the common theme is that excuses based on personal disorganisation, misunderstanding, or the failure of your agent (accountant) are almost guaranteed to fail. The only successful appeals are for events that are truly exceptional and unavoidable.
Step-by-Step: How to Officially Appeal Your Penalty
So, you've received a penalty and you're confident you have a valid, evidence-backed reasonable excuse. What do you do next?
Think of the appeal process as your formal opportunity to state your case. Filing online is like sending a secure, trackable email, while the SA370 form is like sending a 'signed-for' letter. Both are official, but the online method is often faster and provides an instant confirmation.
Step 1: Gather Your Evidence (The Most Critical Step)
Before you write a single word, get your proof. Don't just *say* you were in the hospital; *prove* it. Get copies of hospital discharge letters, bereavement certificates, dated IT repair invoices, or a strongly-worded letter from your GP. Your appeal is only as strong as your evidence.
Step 2: Choose Your Method (Online vs. Paper)
- Online (Recommended): The quickest way is to appeal via your HMRC Government Gateway account. When you log in and view your statement, there is usually an option to "appeal a penalty." This method allows you to state your case and attach digital copies of your evidence directly.
- By Post (Form SA370): If you prefer, or if the online option isn't available, you can download, print, and fill out form SA370 ('Self Assessment: Appeal against penalties for late filing'). You then post this, along with photocopies of your evidence, to the address on the form.
Step 3: Write Your Appeal Clearly and Factually
Whether online or on paper, your explanation should be clear, concise, and factual. Avoid emotion. Stick to the facts:
- What happened? (e.g., "I was admitted to hospital for emergency surgery.")
- When did it happen? (e.g., "The dates of admission were 25th January to 3rd February.")
- How did this prevent you from filing? (e.g., "I was hospitalised and then recovering, with no access to my records.")
- When did you file? (e.g., "As soon as I was able, I filed my return on 10th February.")
Finally, clearly state "I am attaching a copy of my hospital discharge letter as evidence."
What Happens if HMRC Rejects Your Appeal?
So, you sent your appeal with all your evidence, and 6-8 weeks later, you receive *another* letter: "Appeal Rejected." This is disheartening, but it is not the end of the road. You have two further options.
Option 1: Request a 'Statutory Review'
You can ask HMRC to take a second look. This is called a 'statutory review.' Your case will be passed to a different, often more senior, decision-maker within HMRC who was not involved in the first decision. This is a good option if you feel the first reviewer missed a key piece of evidence.
Option 2: Appeal to the First-tier Tribunal (Tax Chamber)
If the review also fails, you can appeal to an independent body: the First-tier Tribunal. This is the UK's independent tax court. It is free to appeal, but it can be a daunting legal process. However, this is where having a truly "reasonable" excuse can finally win out. According to **Ministry of Justice (MOJ) Tribunal Statistics for 2023/24**, a significant number of taxpayers who appeal to the tribunal are successful in having their cases allowed in full or in part. This shows that an independent judge may agree with you even if HMRC's internal reviewers did not, provided your case is strong and well-documented.
Common Questions About 'Reasonable Excuse' Appeals
Based on questions I've seen across UK freelancer forums and Reddit's r/UKPersonalFinance, here are the most common points of confusion.
What's the difference between a reasonable excuse and just a mistake?
The key difference is *control*. A mistake is typically within your control (e.g., "I forgot the deadline," "I put the wrong date in my calendar," "I misread the guidance"). A reasonable excuse is an event outside your control that *prevented* you from filing (e.g., "I was in a coma," "My house burned down with my records").
Will HMRC accept 'my accountant was busy' or 'they gave me bad advice'?
Almost certainly not. HMRC's guidance (and decades of tax law) is built on the principle that the taxpayer is ultimately responsible for their own tax affairs. If you hire an agent (like an accountant), you are responsible for ensuring they do the work on time. Their failure is not your reasonable excuse. Your only recourse would be to pay the penalty and then seek compensation from the accountant, often through their professional indemnity insurance or standards body.
My appeal was rejected by HMRC. Is it really worth taking my case to the First-tier Tribunal?
This depends entirely on the strength of your evidence and the amount of money at stake. As the MOJ statistics suggest, success at the tribunal is absolutely possible for taxpayers with a genuine, well-documented case. It is free, but you must be prepared to present your case clearly. If your penalty is £100 and your excuse is weak (e.g., "my laptop was slow"), it is likely not worth the time. If your penalties are over £1,600 and you have a hospital letter proving you were incapacitated, it is often worth pursuing.
Conclusion: Your Next Steps
Getting a Self-Assessment penalty is stressful, but a 'reasonable excuse' appeal is your formal right as a taxpayer. The key is to act quickly, provide irrefutable evidence, and understand that HMRC's definition of 'reasonable' means 'unexpected and uncontrollable.' Vague excuses about being busy or stressed, or blaming your accountant, will not work.
If you've received a penalty and believe you have a valid, evidence-backed excuse, use the online portal or form SA370 to lodge your appeal, ideally within the 30-day window. For simple cases like a sudden hospital stay, the process can be straightforward. However, for more complex situations (like severe mental health issues) or if your appeal is rejected and you are considering the tribunal, I strongly recommend consulting a qualified tax advisor or accountant. They cannot be your excuse, but they can be an invaluable guide through the appeals process.
About the Author
Alex Williams
Alex Williams is the founder and developer of FinTools UK. Driven by a passion for making complex financial topics accessible, Alex Williams combines development skills with in-depth research to build easy-to-use calculators and write clear, informational articles. The goal is to simplify UK tax and finance for everyone.
Please note: The content on this site is for informational and educational purposes only and should not be considered financial advice. Alex Williams is not a certified financial advisor.