How long do you have to appeal an HMRC penalty? 30 days from the date on the notice, and the three clocks that follow

A client usually has 30 days from the date a penalty was issued to appeal to HMRC, on GOV.UK's guidance read on 1 October 2026. The clock starts from the date printed on the notice, not the day it reaches the client or the practice.

The law is section 31A of the Taxes Management Act 1970: notice of appeal must be given in writing, "within 30 days after" the date the notice was issued, and must state the grounds. Schedule 55 to the Finance Act 2009, which sets the late filing penalties, says a penalty appeal is treated in the same way as an appeal against an assessment.

Four clocks, in order

The wording differs, and it changes the last day. "Within 30 days after" a date gives 30 full days after it. A period "beginning with" a date counts that date as day one, so it ends a day sooner.

GOV.UK says a direct tax penalty, such as one for Income Tax, must be appealed to HMRC before the tribunal. If HMRC does not change its decision, it offers a review. A VAT penalty works differently: the review is offered in the penalty decision letter, and the client has 30 days to accept it or appeal to the tribunal.

A client who ignores a review offer loses by default. Section 49C says that if the offer is not accepted within the 30 days, HMRC's view is treated as agreed, unless the client has taken the appeal to the tribunal.

One penalty, worked through

A client's 2025 to 2026 return was due on 31 January 2027. She was in hospital for three weeks in January and the return went in on 12 February 2027. HMRC issues a £100 late filing penalty, and the practice appeals on 5 March.

The counting: 17 February plus 30 days is 11 days to the end of February and 19 in March. The acceptance period begins on 14 April itself, so its 30th day is 13 May. The last two periods are counted the same way.

If HMRC does not give its conclusions within the 45 days, or a longer period agreed with the client, section 49E treats the review as having upheld HMRC's view, and HMRC must write to say so.

If the 30 days have gone

A late appeal is still possible. Section 49 says notice can be given after the time limit if HMRC agrees or, where it does not, the tribunal gives permission. HMRC must agree where three conditions are met:

1. the client asks in writing for a late appeal to be accepted;
2. there was a reasonable excuse for missing the time limit;
3. the request was made without unreasonable delay after the excuse ended.

What counts as a reasonable excuse

GOV.UK's list of what may count includes the death of a partner or close relative shortly before the deadline, an unexpected stay in hospital, a serious illness, software failing while the online return was being prepared, problems with HMRC's online services, a fire, flood or theft, postal delays nobody could have predicted, and relying on someone else to send the return who did not.

It will not accept a payment that failed for lack of funds, finding HMRC's online system too difficult, not getting a reminder from HMRC, or a mistake on the return.

Relying on someone else is the excuse that lands on a practice, and the statute is narrower than the guidance. Paragraph 23 of Schedule 55 says reliance on another person is not a reasonable excuse unless the taxpayer took reasonable care to avoid the failure. The excuse also lasts only if the failure is put right without unreasonable delay once it has ended. A client who sent records late and blames the practice has to show their own care. The dated requests in our records request letter template are the evidence either way.

Paying while the appeal runs

GOV.UK says a client who has appealed against a penalty does not have to pay it until the appeal is settled. HMRC's Self Assessment guidance still suggests paying: if the appeal is rejected, interest runs on the penalty from the date it was due, and if it succeeds HMRC repays it with interest.

What the practice does

1. Read the date on the notice the day it arrives. Diary that date plus 30 days.
2. Collect what HMRC's appeal tool asks for. The dates the penalty was issued, the return filed and the tax paid, and the details of the excuse.
3. Use the tool on GOV.UK. It says whether the appeal goes online or by post on form SA370 or SA371.
4. Diary every later letter the same way. A review offer and a review conclusion each start 30 days.
5. Check which penalty regime the client is in. GOV.UK says a client in Making Tax Digital for Income Tax gets a letter for each penalty point or penalty, and the letter says how to appeal. Our MTD deadline checker has the points rule.

The amounts being appealed are in our Self Assessment penalty calculator. A Companies House late filing penalty is not an HMRC penalty, and our Companies House penalty calculator covers that appeal.

Overlyft can set up an AI assistant that holds each client's filing dates and tells the partner each morning which are at risk. The appeal and its wording stay with the accountant.

This is general information, not professional advice.