Missing a tax deadline does not always mean that a penalty must stand.
HMRC recognises that unexpected events can prevent taxpayers from filing a return, paying tax or responding to a formal request on time. In these circumstances, the taxpayer may have a reasonable excuse.
However, HMRC does not use one fixed definition that applies to everyone.
Instead, it considers the taxpayer’s individual circumstances, abilities, experience and actions. An event that provides a reasonable excuse for one person may not provide the same excuse for another.
The taxpayer must also show a clear connection between the event and the missed obligation. For example, having an illness is not automatically enough. The taxpayer should explain how that illness prevented them from filing or paying by the deadline.
Timing matters as well. Once the reasonable excuse ends, the taxpayer must normally correct the failure without unreasonable delay.
What Does HMRC Mean by a Reasonable Excuse?
HMRC generally describes a reasonable excuse as something that stopped a person from meeting a tax obligation despite them taking reasonable care.
In practical terms, HMRC will usually consider four questions:
- What exactly happened?
- Did it prevent the taxpayer from meeting the particular obligation?
- How long did the problem continue?
- Did the taxpayer correct the failure without unreasonable delay?
The taxpayer must normally satisfy HMRC, or a tribunal on appeal, that a reasonable excuse existed.
HMRC should consider the full facts rather than reject an appeal merely because the circumstances do not appear on a standard list. Its internal guidance confirms that several events which seem insufficient individually may create a reasonable excuse when considered together.
Which HMRC Penalties Can a Reasonable Excuse Affect?
A reasonable excuse may provide a defence against several types of penalty, depending on the legislation involved.
These may include penalties for:
- filing a Self Assessment tax return late;
- paying certain taxes late;
- submitting a VAT return late;
- failing to comply with an HMRC information notice;
- failing to notify HMRC of a tax liability;
- late PAYE or Corporation Tax obligations;
- missing certain appeal deadlines; and
- obstructing an HMRC inspection.
However, the precise rules differ between taxes and penalties.
For example, an inaccurate tax return usually involves a different test. HMRC will generally consider whether the taxpayer took reasonable care or acted carelessly or deliberately. Therefore, the phrase “reasonable excuse” should not automatically be used for every type of penalty.
A reasonable excuse also does not remove the underlying tax. It may cancel the penalty, but the taxpayer will normally still need to submit the return, pay the tax and settle any interest.
Examples That May Amount to a Reasonable Excuse
HMRC provides examples of circumstances that may support a reasonable-excuse appeal. However, none guarantees success.
The taxpayer must explain how the event affected their ability to comply.
Serious illness or an unexpected hospital stay
A serious physical illness may provide a reasonable excuse if it prevented the taxpayer from dealing with their tax affairs.
For example, a person may have suffered a heart attack shortly before a filing deadline and remained in hospital during the relevant period.
HMRC will consider:
- when the illness began;
- how serious it was;
- whether it affected the taxpayer’s ability to act;
- whether anybody else could reasonably have helped;
- how long the effects continued; and
- when the taxpayer eventually corrected the failure.
A minor illness that did not prevent normal activities may be less persuasive. In contrast, a prolonged recovery or serious treatment may explain a longer delay.
Mental health difficulties
Depression, anxiety, post-traumatic stress disorder and other mental health conditions may provide a reasonable excuse.
However, the diagnosis alone does not decide the appeal.
The taxpayer should explain how the condition affected their ability to:
- understand HMRC correspondence;
- organise records;
- communicate with an adviser;
- make decisions;
- complete the return;
- authorise its submission; or
- arrange payment.
HMRC’s internal guidance recognises that mental health conditions are complex and that it should consider every case on its own facts.
Where available, medical evidence may support the explanation. Nevertheless, the evidence should focus on the relevant period and the practical effect of the condition.
Bereavement
The death of a partner or close relative shortly before a deadline may provide a reasonable excuse.
The strength of the appeal will depend on factors such as:
- the taxpayer’s relationship with the person;
- when the death occurred;
- whether the taxpayer arranged the funeral or estate;
- the emotional and practical effect; and
- how close the event was to the deadline.
A bereavement several years earlier may still have ongoing effects, but the taxpayer will need to explain clearly why it prevented compliance during the particular period.
Fire, flood, theft or another serious incident
A fire, flood, burglary or similar incident may destroy records, prevent access to business premises or make computer systems unavailable.
A successful appeal should normally explain:
- when the incident happened;
- which records or systems it affected;
- why replacements could not be obtained before the deadline;
- what steps the taxpayer took; and
- when they eventually completed the obligation.
Insurance documents, police crime references, photographs, repair invoices or correspondence with software providers may support the account.
Computer or HMRC online-service failure
An unexpected computer or software failure may provide a reasonable excuse if it occurred while the taxpayer was preparing or submitting the return.
Similarly, problems with an HMRC online service may prevent filing.
Useful evidence may include:
- screenshots of error messages;
- service reference numbers;
- emails to a software provider;
- details of calls to HMRC;
- IT repair reports; and
- records showing earlier attempts to submit.
Waiting until the final minutes before a deadline can weaken the appeal, particularly if the taxpayer had enough time to use an alternative filing method.
Unpredictable postal delays
An unexpected postal delay may sometimes provide a reasonable excuse, particularly if the taxpayer allowed a sensible amount of time and retained proof of posting.
However, using ordinary post immediately before a known deadline may not show reasonable care.
A genuine misunderstanding of the obligation
In some cases, not knowing about or misunderstanding a tax obligation can provide a reasonable excuse.
This does not mean that ignorance of the law always excuses non-compliance.
HMRC will consider whether the obligation was difficult to understand and whether the taxpayer acted reasonably. Relevant questions may include:
- Was the rule new or unusually complex?
- Did HMRC provide clear information?
- Did the taxpayer seek appropriate advice?
- Did the taxpayer receive misleading information?
- When should the taxpayer reasonably have discovered the obligation?
Once the taxpayer becomes aware of the requirement, they must normally act promptly.
Circumstances HMRC Will Not Normally Accept
Some explanations will not usually amount to a reasonable excuse without additional facts.
| Explanation | Why it may fail |
| “I forgot the deadline” | Forgetting alone does not normally show that an event prevented compliance |
| “I did not receive a reminder” | Taxpayers remain responsible for knowing their filing and payment dates |
| “I found HMRC’s system difficult” | General difficulty is not the same as an unexpected system failure |
| “I was too busy” | Work pressure or poor organisation will not usually provide a defence |
| “My accountant failed to do it” | Delegating a task does not remove the taxpayer’s responsibility |
| “I did not have enough money” | Lack of funds alone will not normally provide a reasonable excuse |
| “I made a mistake on the return” | Inaccuracy penalties normally involve the reasonable-care test instead |
| “I was on holiday” | A planned absence should usually allow time to make other arrangements |
However, HMRC should still consider the full circumstances.
For example, a shortage of money alone may not amount to a reasonable excuse. Nevertheless, an unexpected event outside the taxpayer’s control that suddenly caused the shortage may support an appeal if the taxpayer paid promptly once funds became available.
Can You Blame Your Accountant?
Relying on an accountant does not automatically provide a reasonable excuse.
Taxpayers remain responsible for meeting their obligations. Therefore, saying “my accountant did not file it” may not be enough.
However, reliance on another person may contribute to a reasonable excuse if the taxpayer took reasonable care. HMRC may consider whether the taxpayer:
- appointed a suitably qualified or experienced adviser;
- supplied the records in good time;
- explained what needed to be done;
- agreed a clear deadline;
- responded promptly to questions;
- checked progress;
- chased the adviser where necessary; and
- had any reason to believe that the return had not been filed.
HMRC’s guidance confirms that reliance may amount to a reasonable excuse where the taxpayer took reasonable care to prevent the failure.
The taxpayer should therefore provide emails, engagement letters and evidence of supplying information rather than simply blaming the adviser.
What Does “Without Unreasonable Delay” Mean?
A reasonable excuse does not continue indefinitely.
Once the event that prevented compliance ends, the taxpayer must put matters right without unreasonable delay.
There is no universal number of days that applies in every case. HMRC should consider how long it was reasonable for that taxpayer to take.
For example, after leaving hospital, a taxpayer may still require time to recover, obtain records and instruct an accountant. However, doing nothing for several more months without explanation could weaken the appeal.
HMRC’s approach involves identifying when the excuse ended and then examining what the taxpayer did afterwards.
This part of an appeal is often as important as the original event.
A strong appeal should therefore include:
- the date the problem began;
- the date of the missed obligation;
- the date the problem ended or became manageable;
- the steps taken after that date; and
- the date the return, payment or response was completed.
What Evidence Should Support the Appeal?
HMRC should consider credible explanations even where formal documents are limited. Nevertheless, independent evidence can make the appeal stronger.
Depending on the circumstances, useful evidence may include:
- hospital admission and discharge dates;
- medical letters or appointment records;
- a death certificate or funeral information;
- police or insurance reports;
- photographs of flood or fire damage;
- IT repair invoices;
- screenshots of online errors;
- proof of posting;
- correspondence with HMRC;
- emails exchanged with an accountant;
- bank records showing an unexpected loss of funds;
- a dated timeline of events; and
- evidence showing when the failure was corrected.
Medical evidence does not always need to reveal every private detail. It should provide enough information to support the period and effect of the condition.
The appeal should also remain accurate. Exaggerated or inconsistent claims may damage the taxpayer’s credibility.
How to Write a Reasonable-Excuse Appeal
A useful appeal should remain clear, factual and specific.
It should include:
- the taxpayer’s name and tax reference;
- the date and reference of the penalty notice;
- the tax and period involved;
- the amount of the penalty;
- the obligation that was missed;
- what happened and when;
- how it prevented compliance;
- when the excuse ended;
- how quickly the failure was corrected;
- a list of supporting evidence; and
- a request for HMRC to cancel the penalty.
Avoid writing only:
“I was ill and could not file.”
Instead, explain the effect:
“I was admitted to hospital unexpectedly on 25 January and remained there until 8 February. During that period, I could not access my business records or authorise my accountant to submit the return. I contacted my accountant on 10 February and the return was submitted on 12 February.”
The second explanation gives HMRC a timeline and connects the illness directly to the missed deadline.
How Long Do You Have to Appeal?
The penalty notice should explain how to appeal and the applicable deadline.
For many HMRC penalties, the taxpayer has 30 days from the date of the penalty decision to submit an appeal. For example, HMRC’s Self Assessment appeal form instructs taxpayers to send it within 30 days of the date shown on the penalty notice.
Do not delay the appeal while waiting for every supporting document.
Where necessary, submit the appeal before the deadline, explain that further evidence will follow and send that evidence as soon as possible.
If the deadline has already passed, the taxpayer should explain both:
- the reasonable excuse for the original tax failure; and
- the reason the penalty appeal itself was late.
These are two separate issues.
What Happens If HMRC Rejects the Appeal?
If HMRC rejects the reasonable-excuse appeal, the taxpayer may be able to:
- provide further evidence;
- ask HMRC to review the decision;
- accept an offer of a statutory review; or
- appeal to the First-tier Tribunal.
A statutory review normally involves an HMRC officer who was not involved in making the original decision.
If the dispute continues, an independent tribunal can consider whether the taxpayer had a reasonable excuse.
Before continuing, the taxpayer should review:
- the strength of the evidence;
- the relevant legislation;
- HMRC’s reasons for rejecting the appeal;
- any inconsistencies in the explanation;
- the value of the penalty; and
- the time and cost involved.
The fact that HMRC rejected the first appeal does not necessarily mean that its decision is correct.
Reasonable Excuse and Special Circumstances Are Different
A taxpayer may fail the reasonable-excuse test but still have circumstances that justify reducing the penalty.
Some penalty rules allow HMRC to make a special reduction where special circumstances exist.
This is a separate consideration. Special circumstances should normally be unusual, exceptional or relevant to the fairness of the penalty. They cannot simply repeat the normal features already built into the penalty rules.
For example, a taxpayer might not have had a continuous reasonable excuse for the entire period, but an unusual combination of events may make the full penalty disproportionate.
HMRC should consider special reduction where the relevant legislation allows it. However, taxpayers should identify the circumstances clearly rather than assume HMRC will apply a reduction automatically.
Practical Guide
- Check the penalty notice, tax period and appeal deadline
- Correct the outstanding return, payment or response immediately
- Create a dated timeline of what happened
- Explain how the event prevented the particular obligation
- Identify when the reasonable excuse ended
- Show that you acted without unreasonable delay afterwards
- Collect independent supporting evidence
- Submit the appeal within the stated deadline
- Keep copies and proof of submission
- Consider a statutory review or tribunal appeal if HMRC rejects it
- Ask HMRC to consider special circumstances where appropriate
- Put a system in place to prevent another missed deadline
Most importantly, submit the outstanding return or pay the tax as soon as possible. An appeal against the penalty does not remove the underlying obligation.
Frequently Asked Questions
Is being ill always a reasonable excuse?
No. HMRC will consider the seriousness, timing and practical effect of the illness. The taxpayer should explain how it prevented them from meeting the particular obligation.
Does depression or anxiety count as a reasonable excuse?
It can. The diagnosis alone is not enough, however. The appeal should explain how the condition affected the taxpayer’s ability to understand, organise or complete their tax affairs during the relevant period.
Can lack of money provide a reasonable excuse?
Lack of funds alone does not normally qualify. However, an unexpected event outside the taxpayer’s control that directly caused the shortage may support an appeal, particularly if the taxpayer paid promptly afterwards.
Is forgetting the deadline a reasonable excuse?
Usually not. HMRC expects taxpayers to know their filing and payment deadlines and put suitable reminders in place.
Can I appeal because my accountant filed the return late?
Possibly, but blaming the accountant alone will not normally succeed. You should show that you appointed the adviser in good time, supplied the information, agreed the deadline and took reasonable steps to check progress.
Do I need medical evidence?
Not in every case. However, relevant evidence can strengthen an appeal, particularly where the illness continued for a long period or HMRC questions its effect.
Can HMRC cancel interest as well as the penalty?
A successful reasonable-excuse appeal normally concerns the penalty. Late-payment interest follows separate rules and may continue to apply even if HMRC cancels the penalty.
What if several problems happened at the same time?
Explain all of them. HMRC’s guidance recognises that several events, considered together, may amount to a reasonable excuse even if one event alone would not.
Can a company have a reasonable excuse?
Yes. However, HMRC will examine the people and systems through which the company acts. A company should explain why its directors, employees or agents could not reasonably meet the obligation.
Where to Find Official HMRC Information
You can find current guidance here:
- Reasonable excuses when challenging a tax decision or penalty, including HMRC’s public examples.
- HMRC Compliance Handbook: reasonable excuse, covering illness, mental health, reliance on others and other circumstances.
- HMRC guidance on what reasonable excuse means, explaining the individual nature of the test.
- How HMRC establishes whether a reasonable excuse exists, covering evidence and unreasonable delay.
- Appeal against a tax decision or penalty, explaining reviews and tribunal appeals.
- Get extra support from HMRC, for taxpayers whose health or personal circumstances make dealing with HMRC difficult.
The applicable rules depend on the tax, penalty and relevant legislation. Therefore, always check the penalty notice and current guidance.
💡 Key Takeaway
A reasonable excuse is not simply a reason why a deadline was missed.
The taxpayer must normally show that a genuine event prevented compliance, that the event affected them during the relevant period and that they corrected the failure without unreasonable delay once they could act.
The strongest appeals include a clear timeline, supporting evidence and a direct connection between the circumstances and the missed obligation.
Even where HMRC rejects the first appeal, the taxpayer may still request a review or ask an independent tribunal to consider the case.
Need Help?
If HMRC has charged you a late-filing, late-payment or other compliance penalty, Accounts Tax Group can review whether the facts may support a reasonable-excuse appeal.
We can examine the penalty notice, prepare a clear timeline, identify useful evidence and submit a structured appeal to HMRC. Where HMRC has already rejected the explanation, we can also review the available next steps.
Contact Accounts Tax Group promptly, as most penalty appeals have strict time limits.
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