A reasonable excuse is something that stopped you meeting a tax obligation despite taking reasonable care, such as a serious illness, a bereavement shortly before the deadline, a fire or flood, or a failure of HMRC’s online services. If you have one, you can appeal a penalty, usually within 30 days of the date it was issued. Lack of money, finding HMRC’s systems difficult, or not getting a reminder do not count.

What does HMRC accept as a reasonable excuse?

GOV.UK gives these examples:

  • your partner or another close relative died shortly before the deadline;
  • you had an unexpected stay in hospital;
  • you had a serious or life threatening illness;
  • your computer or software failed while you were preparing your return;
  • HMRC’s online services had problems;
  • a fire, flood or theft prevented you;
  • postal delays you could not have predicted;
  • a disability or mental health condition prevented you;
  • you were unaware of, or misunderstood, a legal obligation, in some circumstances;
  • you relied on someone else to file and they did not, in some circumstances.

Whatever the reason, you must put things right as soon as you can once it has gone.

What does not count?

  • a payment failed because there was not enough money;
  • you found HMRC’s online system too difficult to use;
  • you did not get a reminder from HMRC;
  • you made a mistake on your return.

How do I appeal a penalty?

GOV.UK says you usually have 30 days from the date the penalty was issued to appeal. If you appeal late, you must explain why. HMRC may offer a review, and you can take the appeal to the tax tribunal. See statutory review and the tax tribunal.

Does reasonable excuse apply to inaccuracy penalties?

Penalties for errors in returns work differently. They depend on whether you took reasonable care, and whether the error was careless or deliberate. See HMRC penalties for tax return errors and suspended penalties. For failing to register, see failure to notify penalties.

Who pays for help with an appeal?

A simple late filing appeal is often something you can do yourself. Disputes that arise from an HMRC enquiry need more work.

Tax investigation insurance pays your accountant’s fees if HMRC opens a check after your cover starts. Solar Protect cover pays up to £100,000 with no excess. It never pays tax, interest or penalties. Read how our cover works or get a quote today.

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 7 October 2026. Sources: GOV.UK, Tax appeals: reasonable excuses; GOV.UK, Appeal a penalty. This guide is general information, not personalised tax advice.