There is no statutory clock on an HMRC investigation: no rule sets a date by which a compliance check must finish. How long one takes is decided by four things: how wide the check is, how quickly and completely HMRC's questions are answered, whether the figures end up in dispute, and the route by which it closes. A narrow question about one entry on one return can be dealt with in an exchange of letters; a full review of a business's records, or a case where HMRC suspects deliberate behaviour, is a different undertaking altogether. GOV.UK's compliance checks guidance sets out the framework. For how the compliance check process itself works, see our guide to HMRC's compliance check service.
What decides how long a check takes?
Scope is the biggest lever. HMRC's opening letter says what it is checking, from one aspect of one return to everything, and the scope can widen later: an enquiry into a return can extend to anything in it. The rest is largely in your hands. The table sets out what tends to move the timetable in each direction.
| Factor | Tends to shorten the check | Tends to lengthen it |
|---|---|---|
| Scope | A single aspect of a single return | Full returns, several years, or connected company and personal affairs |
| Records | Complete, organised, reconciled | Missing, reconstructed, or contradicting the returns |
| Responses | Prompt, complete answers through one channel | Late or partial replies that invite follow-up rounds |
| The figures | Agreed or narrowed early | Disputed valuations, estimates or behaviour arguments |
| Behaviour | An error accepted and corrected | Suspected deliberate conduct, which changes the process itself |
What are the stages of an HMRC compliance check?
Most checks move through the same sequence:
- An opening letter saying what HMRC is checking and asking for information or documents
- Review rounds: HMRC works through what you send and comes back with questions
- Meetings or visits: HMRC may ask to visit your business, your adviser's office, or your home if you run your business from there, or ask you to visit them, and you can have an accountant or legal adviser with you at a visit (both points are in GOV.UK's guidance)
- A position: HMRC sets out what it thinks the right figures are and why
- Closure: agreement or amended assessments, penalties where they are due, and your rights if you disagree
The cycle in the middle is where time is won or lost. An incomplete answer can buy another round.
What can HMRC ask you for?
The opening letter usually asks for information and documents relevant to what is being checked: business records, bank statements, invoices, working papers behind a return. Relevance is the boundary that matters. A check into one year's property pages is not an open door to a decade of personal bank statements, and part of an adviser's job is holding requests to the scope HMRC itself has defined, politely and in writing.
Visits follow the same logic. GOV.UK's guidance is explicit that HMRC may ask to visit your business, your adviser's office, or your home if you run your business from there, or ask you to come to them, and that you can have an accountant or legal adviser with you. A visit is rarely the first step, and where one is proposed, the venue, the agenda and who attends are all things to settle in advance rather than improvise on the day.
Two behaviours slow checks down more than any tactic: guessing (an answer that later needs correcting reopens settled ground and dents credibility on everything else) and over-supplying (handing over more than was asked invites questions the check never contained). Answers that cover what was asked, fully, with evidence and in one go, can leave less to follow up.
Can you speed an investigation up?
You cannot set HMRC's pace, but you can remove every reason for delay on your side. The factors on your side are replies by the dates given, complete answers, one channel of correspondence rather than parallel letters, a reconciliation sent with the records HMRC asked for so that it reviews an analysis instead of building one, and a written question, once everything has been answered, about what remains open. For an enquiry into a return, you can also ask the tax tribunal to direct HMRC to close it within a specified time.
If you reach deadlock, HMRC's closing decisions are not the end of the road: assessments and penalty decisions carry rights of review and appeal, with deadlines that matter.
When does an enquiry become serious?
Watch for the scope widening from one aspect to whole returns, questions shifting from what happened to why it happened, requests reaching back across more years, or any mention of Code of Practice 8 or 9. Those are the markers of an investigation changing character. Our Code of Practice 9 page explains the serious-fraud procedure, and our guide to how far back HMRC can investigate covers the time limits that open up as behaviour worsens.
Example
Example. Two checks, two shapes. First, a company receives a full enquiry into a year's return: sales cut-off, directors' loans and expenses are all in scope. Its records are complete but scattered across systems, so the adviser's first move is assembling one reconciled bundle before answering anything, and the check proceeds in defined rounds: information, questions, a meeting at the adviser's office, positions exchanged, figures agreed. The scope was wide, so the check was long; it did not become open-ended; every HMRC letter got a complete answer and a written question back: what remains open?
Second, a landlord receives a check into the property pages of one return. With her adviser she assembles the letting statements, the mortgage interest certificates and a bank reconciliation, and finds the deposit HMRC had matched against her account was a tenancy deposit later repaid, not rent. The adviser sends the reconciliation with a short covering analysis answering each question in HMRC's letter, and invites any remaining questions in one list. HMRC raises one follow-up on repairs, accepts the evidenced answer, and closes the check with no change. The same check handled with drip-fed bank statements and unanswered questions could have run to more rounds on the same facts.
What this means in practice
The letter in front of you sets the date to reply by and names the years and entries in question, and the records for those are the starting point for any answer. If the letter hints at behaviour, or mentions COP8 or COP9, it is a more serious check, and one to take advice on before replying: our tax investigations page explains how we take these over, including part-run enquiries that have stalled.
Frequently Asked Questions
HMRC has a limited window to open an enquiry into a filed return, and separate, longer time limits to assess tax it believes was lost. Those limits stretch as the behaviour involved worsens, from ordinary error through carelessness to deliberate conduct. Our guide to how far back HMRC can investigate covers the detail.
You do not have to agree to a meeting, but a formal inspection or information notice cannot be ignored, and refusing one can mean a penalty. HMRC says it will only ask to visit your home if you run your business from there. HMRC may ask to visit your home, business premises or your adviser's office, or ask you to visit them. You can have an accountant or legal adviser with you during a visit, and the adviser's office is often the sensible venue. How a visit request is handled is worth agreeing with your adviser before you reply.
For a narrow query about one figure, some people do. The case for an adviser strengthens quickly as the scope widens, more years are pulled in, or the questions move from the figures to your behaviour, because answers given early become part of the record HMRC works from for the rest of the check.
Closing decisions, amended assessments and penalties carry rights of review and appeal, and the deadlines for using them are short. Disagreeing is a process, not a stand-off: the routes include setting out the evidence, a review by HMRC, and an appeal to the tax tribunal.
Representation is something HMRC's Charter provides for: it says HMRC will respect your wish to have someone else, such as an accountant, deal with it on your behalf, and GOV.UK's guidance covers authorising an agent for a check. An authorised adviser can deal with HMRC on your behalf and help make each response complete.
Talk to us about a live check
If a compliance check has opened, or one has stalled, speak to Ghulam Alahi, Managing Director, who has more than 25 years' experience in HMRC enquiry work. We can talk through what HMRC has asked for and what needs to be provided. Call 020 8554 2135 or email info@visionconsulting.co.uk, or use our contact page.
By the Vision Consulting team.
This is general information, not advice. Your position depends on your circumstances. Speak to us before acting.