The short answer: a compliance check letter means HMRC wants to check part of your tax position. It does not mean you have done something wrong. Read the letter carefully, note the deadline, gather the records asked for and get advice before you reply. You have the right to be represented, and you must not ignore a formal information notice.
What a compliance check is
HMRC uses compliance checks to make sure people and businesses are paying the right amount of tax at the right time and getting the right allowances and reliefs. HMRC will write or phone to say what they want to check. A check can cover one return or several taxes, including Income Tax, VAT, PAYE and Corporation Tax.
What to do, step by step
- Make sure it is genuine. If you are unsure, contact HMRC using the details on gov.uk, not a number or link in an unexpected message.
- Read what HMRC wants and by when. Note the deadline. If you need more time, ask HMRC before it passes.
- Get advice. You can appoint an accountant to deal with HMRC for you. They will check your records before anything is sent.
- Gather your records. Bank statements, invoices, receipts and the workings behind your return.
- Answer accurately and only what is asked. Clear, complete answers usually help the check finish sooner.
- If something is wrong, say so. Telling HMRC about a mistake and helping them can reduce any penalty.
Can I ignore it?
No. If HMRC sends a formal information or inspection notice and you do not provide what is asked, HMRC may use its legal powers to get it, and penalties can follow. You cannot choose to ignore an information or inspection notice.
How long can HMRC take to start a check?
For a Self Assessment return filed on time, HMRC can normally open an enquiry up to 12 months after the date the return was delivered. Different time limits apply to late or amended returns.
How the check ends
When HMRC has finished, it sends a decision or agrees a settlement with you. If you paid too much, you are repaid. If you owe more, you usually have 30 days to pay it, with interest. A penalty may also be charged if a mistake was careless or deliberate. If you disagree, you can write to HMRC with your reasons, ask for a review or use alternative dispute resolution.
How we help
We read the letter with you, deal with HMRC for you, prepare the schedules and reconciliations they need and keep the check focused. See help with HMRC enquiries and penalty appeals.
Sources: gov.uk, Tax compliance checks; About compliance checks (CC/FS1a); HMRC Self Assessment Manual SAM31100. Checked 6 October 2026.
Common questions
Does a compliance check mean I am being investigated for fraud?
No. Most compliance checks are routine checks of a return or a particular figure. If HMRC suspects fraud, it uses separate procedures and you should get specialist advice straight away.
Can my accountant deal with HMRC for me?
Yes. You have the right to be represented and can appoint an adviser to act for you.
What if I need more time to send the information?
Ask HMRC before the deadline. HMRC asks you to tell them if you need more time.
Will I have to pay a penalty?
Not if you took reasonable care. If a mistake was careless or deliberate, a penalty may be charged, and it is reduced for telling HMRC, helping them and giving access to your records.
General information only, not personal advice. Tax rules, rates and thresholds change, so check gov.uk or speak to us about your own situation.