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What counts as a reasonable excuse for filing an online return late?

When filing a return online, you should do everything possible to meet the deadline. If you file a return late and you don't have a 'reasonable excuse' you may have to pay a penalty.

This guide provides an overview of what HM Revenue & Customs (HMRC) may generally consider to be a reasonable excuse. It sets out what you should do if you want to appeal against a late filing penalty. It also contains specific guidance for Self Assessment, VAT and Corporation Tax, with links to forms you can use to make your reasonable excuse claim.

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Reasonable excuse - some examples

Generally, a 'reasonable excuse' is when some unforeseeable or unusual event beyond your control has prevented you from filing your return on time. For example:

  • a failure in the HMRC computer system
  • your computer breaks down just before or during the preparation of your online return
  • a serious illness, disability or serious mental health condition has made you incapable of filing your tax return
  • you registered for HMRC Online Services but didn't get your Activation Code in time

Remember, these are just examples. They can only apply if the problem actually prevented you from filing your return on time when you otherwise would have done. Each case is unique and will be considered on its own merits. You should still always send your tax return as soon as you can.

HMRC will not accept an excuse where you haven't made a reasonable effort to meet the deadline. For example, you:

  • found the online system too complicated to follow
  • left everything to your accountant to do and they let you down
  • forgot about the deadline
  • did not try to re-submit your return on time once a problem with the IT system was put right
  • registered for HMRC Online Services after the filing deadline (eg 31 January for Self Assessment)


Problems with HMRC Online Services

You first need to be sure that there is a genuine issue with HMRC Online Services, you may just have filled something in incorrectly. You also need to check that, if there is an issue, there is no work-round in place.

Check you have completed everything correctly

If the system won't accept your online return it's important to check you have filled in all the relevant boxes in the correct format. Where you do find an error you can normally correct it and re-send your return.

Check for service issues and error messages

If you have checked everything, but the HMRC service won't accept your return, you should:

  • print or make a note of any error message details
  • check the link below for any known problems with the service and to get further advice
  • contact HMRC's Online Services Helpdesk if you're still having problems

If you can't submit your return online by the deadline, you should send it online as soon as you can.

Read about current service issues affecting HMRC's Online Services

Online Service Helpdesk - contact details

VAT Online Services Helpdesk - contact details


Problems with your own equipment or software

If you find that you can't file your return online due to a problem with your own computer or software provider then you will need to:

  • check with your software provider as part of your normal support arrangements
  • save, print or make a note of the error message details - this will allow your provider to help you and you may also need it to explain why your return was late

If you can't submit your return online by the deadline, you should send it online as soon as you can.



HMRC expects customers with a disability to meet their tax obligations on time. If a customer who has a disability claims their disability has prevented them from meeting a deadline, HMRC will, of course, consider the claim. They will take into account whether the customer made every reasonable effort to get things done on time. HMRC does not usually accept the same reasonable excuse more than once. If customer has a disability which might affect meeting their tax obligations on time, HMRC will consider whether it would be reasonable for the customer to have plans in case that happened.


Making a claim for reasonable excuse

If you think you have a reasonable excuse for filing late - or for filing a Corporation Tax return in the wrong format - then you should contact HMRC immediately. This is especially important if HMRC has charged a penalty and you wish to appeal against it. You will need to provide:

  • your name (or your client's name if you are acting on behalf of someone else)
  • your authorised agent name, address and contact details (if acting on behalf of someone else)
  • your reference number - for example, your Self Assessment Unique Taxpayer Reference (UTR), your VAT registration number, your Corporation Tax reference number, etc
  • full details of why you filed your online return late
  • the date you tried to file your return online with details (or a copy print out) of the IT system error message

HMRC does not want to penalise customers who would have filed on time but were prevented from doing so by events beyond their control. For this reason a reasonable excuse claim received without details of the IT error message will still be considered.

You must make your reasonable excuse claim in writing and send it to your HMRC Office. HMRC provides forms to help you make a Self Assessment, VAT or Corporation Tax reasonable excuse claim. Using these forms correctly will allow HMRC to consider your reasonable excuse claim more easily.

Please note: these reasonable excuse forms were developed jointly by HMRC and accountant representatives from the accountancy bodies. But they can be used by anyone - not just tax agents and advisers.

Self Assessment tax returns and penalties

If you miss the online tax return deadline and have a reasonable excuse for doing so, you should complete the reasonable excuse claim form straight away. You can only use this form for late online tax returns. Send it back to your HMRC Office. You'll find the address on Self Assessment letters and statements. You can still use the form if you have received a penalty for a late tax return. You have 30 days from the date of the penalty notice to do this.

HMRC will write to you and let you know if they agree that you had a reasonable excuse.

Download HMRC's Self Assessment reasonable excuse claim form (PDF 144K)

Appeals against HMRC tax decisions - find out more


If you don't pay your VAT Return online by the deadline date, you may have to pay a surcharge. A surcharge is an additional amount you may have to pay if you don’t pay your VAT return on time. You won't have to pay a surcharge if you have reasonable excuse for being late. To do this, you can download the form below, complete it and send it to HMRC to make your reasonable excuse claim.

If HMRC agrees that you have a reasonable excuse, they will cancel the surcharge. If HMRC does not accept that you have a reasonable excuse, you will be told how you can take the matter further if you do not agree the decision.

Follow the links below to download a flow diagram and explanation. This will guide you through what you need to do to submit your VAT Return online and who to contact if you're having problems. This diagram will help you decide if you have a reasonable excuse. It also explains what you’ll need to do if you make your VAT Return payment by Direct Debit via HMRC’s VAT Online service.

Download HMRC's VAT Return online filing flow diagram (PDF 30K)

Download HMRC's VAT reasonable excuse claim form (PDF 85K)

Contact HMRC about VAT

Corporation Tax

Company Tax Returns for accounting periods ending after 31 March 2010 must be submitted online and related payments made electronically. In addition, computations must be submitted in Inline eXtensible Business Reporting Language (iXBRL) format. Generally, you must send the accounts forming part of your Company Tax Return in iXBRL format, although there are some exceptions where PDFs are acceptable.

Many companies - and their tax agents and advisers - use HMRC's Corporation Tax Online service to successfully submit their returns in the correct format but IT problems can occur and things can sometimes go wrong. HMRC will take a sympathetic approach where you have made all reasonable attempts to submit your Company Tax Return online using iXBRL, but have been unable to do so due to an IT issue beyond your control.

More on HMRC's online filing requirement and the help available

Read HMRC's approach to managing the transition to online filing (PDF 29K)

If you encounter an IT issue which falls within the approach outlined above, and which prevents you from being able to send the return online using iXBRL you may be allowed further time to file online or, exceptionally, to file on paper where this is the only realistic alternative.

Follow the links below to download a flow diagram to help you submit your Company Tax Return online. This diagram will help you decide if you have a reasonable excuse, so please read it before you download the form to make a claim. You need to complete this form if any of the following applies:

  • You're submitting your online return late due to IT problems.
  • You're sending a paper return to HMRC.
  • Your online return includes accounts/computations as a PDF file where it should be an iXBRL file

Download HMRC's Company Tax Return online filing flow diagram (PDF 30K)

View a narrative version of the online filing flow diagram (PDF 28K)

Download HMRC’s Corporation Tax reasonable excuse claim form (PDF 94K)

If you think you have a reasonable excuse, please attach your form to your online return and submit it to HMRC. If you are submitting a paper return, your form should accompany it.

Whilst each case will be considered individually, if an IT issue affects a number of companies, it may be possible to consider the position collectively. Please be aware that HMRC may not always be able to tell you their decision immediately.

Contact your Corporation Tax Office


More useful links

Self Assessment tax return: deadlines and penalties

Penalties for mistakes and delays with your VAT

Penalties for submitting a VAT Return on paper instead of online

PAYE/National Insurance payments and deadlines

Deadlines and requirements for Corporation Tax

CIS: late return and late return penalties

SDLT filing and payment deadlines

Telephone or write to an HMRC Office

Read more about grounds for reasonable excuse (SAM 10090)