I've received a letter from HMRC about a compliance check, what do I do?

The first thing to establish is what kind of letter you have. HMRC compliance checks range from a simple request for a few figures to a full enquiry into a Self Assessment or Corporation Tax return. The letter should say which tax is involved, which year or accounting period is under review, and what HMRC wants from you. Read it twice before doing anything else, and check the name and phone number of the caseworker so you know who you're dealing with.

Next, look for a deadline. Compliance check letters usually give you a specific date to respond by, and information notices issued under Schedule 36 Finance Act 2008 will typically ask for records within a set period. Missing that date without explanation can escalate matters unnecessarily, so mark it clearly and start working backwards from it.

It's also worth checking the letter is genuine before you send anything sensitive. HMRC does not ask for bank details or payment by unusual methods in a first compliance letter, and genuine letters reference a real return or period you've filed.

Once you know what's being asked, pull together the records that relate to it: invoices, bank statements, expense receipts, payroll records, or whatever the letter specifies. Keep copies of everything you send, and use a covering letter or email that lists what's enclosed, so there's a clear record of what HMRC has received and when.

If the letter is vague about what documents are needed, it's reasonable to ask HMRC to clarify before you gather everything you own. A well-targeted response is more useful to HMRC and less risky for you than an over-disclosure that opens further questions.

Where you don't have a document, say so rather than guessing. Explaining that a record no longer exists, and why, is generally safer than providing an approximate or reconstructed version without flagging it as such.

Simple, factual requests, such as confirming a date or sending a single invoice, can often be dealt with directly. But if the check touches on your income, expenses, dividends, or anything where interpretation of the rules matters, it's worth having an accountant review the letter before you reply.

An adviser experienced in HMRC compliance work can help you understand what's actually being tested, whether the request is proportionate, and how to phrase your response so it doesn't inadvertently invite a wider enquiry.

This is particularly relevant for limited company directors, where personal and company tax positions interact through dividends, director's loans, and benefits in kind, and where a badly worded reply on one issue can prompt questions on another.

HMRC will review what you've sent and either close the check, ask follow-up questions, or move to a more formal enquiry stage. Response times vary, so don't assume silence means the matter is closed; ask for confirmation in writing once you believe things are resolved.

If HMRC proposes an adjustment to your tax bill, you'll usually receive a written explanation and the chance to respond before anything is finalised. Understanding this stage matters because it's where a well-supported case can prevent an unnecessary assessment or penalty.

Ignoring a compliance check letter, or responding carelessly, risks the check dragging on longer than it needs to and can increase the chance of penalties for careless or inaccurate information. Professional fees to resolve a mismanaged enquiry are usually higher than the cost of getting advice early.

Growth plan clients receive tax investigation insurance as standard, which covers professional representation costs if a compliance check becomes a full enquiry. See /fees for how the plans compare.

Don't assume a compliance check letter is a mistake and put it aside; verify it and act on the stated deadline.

Don't send more documents than requested in the hope of appearing cooperative; it can generate new questions.

Don't discuss the check informally by phone without a written record; confirm anything agreed on a call by email or letter afterwards.