How long does an HMRC enquiry take

Q: What timetable is HMRC meant to work to?

Several parts of HMRC's own guidance set the pace: Opening letter. EM1580 says the first informal request should state a date and that officers are encouraged to agree a time limit of normally at least 30 days, with an extra week for enquiries opened between 1 and 20 December and two extra weeks for those opened between 21 December and 31 January. Turnaround. EM1814 says officers, taxpayers and agents should aim to work within a 15 working day turnaround, and should agree a realistic timetable at the start. Expected completion. EM1813 says the officer's intervention plan may estimate how long it will take to obtain and examine the information, and that in suitable cases the officer must tell the taxpayer or agent the date by which they expect to finish examining the records. After meetings. EM1855 says the taxpayer should leave knowing what is needed and by when, and the officer should undertake to deal with things promptly.

Q: How can you move a slow enquiry forward?

Reply fully and on time. Answer every question and say clearly if something does not exist. A partial answer usually brings another letter. Ask for a timetable. Ask the officer what is still needed and when they expect to finish, as EM1813 and EM1855 contemplate. Offer a meeting. A focused meeting with an agenda can deal with several points at once (see meeting HMRC in an enquiry). Ask for a partial closure notice on issues that are already resolved (see partial closure notices). Use alternative dispute resolution. HMRC's guidance says ADR can be used where progress in an enquiry has stalled, but not for complaints about HMRC delay. Apply to the tribunal for a closure notice. Under section 28A(4), or paragraph 33 of Schedule 18 for a company, the taxpayer can apply at any time. The tribunal must direct HMRC to close the enquiry within a set period unless HMRC shows reasonable grounds for not doing so. EM1984 notes that some agents apply routinely once a period, perhaps a month, has passed after records were supplied without a substantive reply. Complain about delay. Delay is a service issue, handled through HMRC's complaints process and then the Adjudicator (see HMRC complaints and the Adjudicator).

There is no fixed time limit on an HMRC enquiry once it has been opened: it stays open until HMRC issues a closure notice. A narrow check of one entry can be finished after a single exchange of letters, while a full enquiry into business records can run on for a long time, especially if it spreads to earlier years. HMRC does not publish standard durations, but its own guidance sets turnaround targets, and a taxpayer can apply to the tribunal to force an enquiry to close.

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Is there a time limit on an HMRC enquiry?

The law limits when HMRC can open an enquiry, not how long it can last. Section 9A of the Taxes Management Act 1970 (TMA 1970) and paragraph 24 of Schedule 18 to the Finance Act 1998 give HMRC a window, generally 12 months from delivery of a return filed on time, to give notice of enquiry (see the enquiry window). After that, section 28A says the enquiry is completed only when an officer issues a final closure notice. There is no end date written into the legislation.

HMRC accepts that this can be a burden. Its Enquiry Manual at EM1814 says that in some enquiries the volume and complexity of the issues make a long enquiry inevitable, but that in others the time taken is unnecessarily long, which is often a factor in complaints.

How long do aspect, full and VAT checks take?

HMRC does not publish average durations for each type of check, and we have not found an official figure, so treat any number quoted elsewhere with caution. What can be said is how the type of check shapes the timetable.

Aspect enquiries. EM1575 tells officers to concentrate the opening request on the documents relevant to the point being checked and to ask for everything they will need in that first letter. EM1580 says simple, limited information in an aspect enquiry may even be gathered by phone. If the answer supports the return, the enquiry can close after one round of correspondence. Delays usually come from third party input, such as a property valuation.
Full enquiries. EM1561 lists what a full enquiry into a business may cover: books and prime records, bank reconciliations, private drawings and the director’s loan account. These usually involve reviewing records, often a meeting, follow up questions and then negotiation of any settlement. If errors are found, EM1835 notes the enquiry may extend into earlier years, which adds time.
VAT checks. A VAT check is not an enquiry into a self assessment return and there is no closure notice. It often centres on a visit to inspect records (see HMRC VAT compliance checks). The outer limit is set by the assessment rules: section 73(6) of the VAT Act 1994 requires an assessment within two years after the end of the VAT period or one year after HMRC has enough evidence, whichever is later, subject to the overall limits in section 77.

The practical difference between the first two types is covered in aspect versus full enquiries.

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What timetable is HMRC meant to work to?

Several parts of HMRC’s own guidance set the pace:

Opening letter. EM1580 says the first informal request should state a date and that officers are encouraged to agree a time limit of normally at least 30 days, with an extra week for enquiries opened between 1 and 20 December and two extra weeks for those opened between 21 December and 31 January.
Turnaround. EM1814 says officers, taxpayers and agents should aim to work within a 15 working day turnaround, and should agree a realistic timetable at the start.
Expected completion. EM1813 says the officer’s intervention plan may estimate how long it will take to obtain and examine the information, and that in suitable cases the officer must tell the taxpayer or agent the date by which they expect to finish examining the records.
After meetings. EM1855 says the taxpayer should leave knowing what is needed and by when, and the officer should undertake to deal with things promptly.

What makes an enquiry drag on?

Delay can come from either side. On the taxpayer’s side, the most common causes are slow or partial replies, incomplete records, difficulty explaining cash or private spending, and changing explanations. EM1590 says that if information is not produced by the date in the opening letter, the officer should issue a formal information notice, which adds another stage. On HMRC’s side, EM1813 recognises that sickness or staff changes can cause delay and that the officer should at least tell the taxpayer. Other causes include waiting for valuations or third party information, enquiries into a company and its director that must move in step, disagreement about the facts, and an enquiry being widened to other entries or years.

How can you move a slow enquiry forward?

Reply fully and on time. Answer every question and say clearly if something does not exist. A partial answer usually brings another letter.
Ask for a timetable. Ask the officer what is still needed and when they expect to finish, as EM1813 and EM1855 contemplate.
Offer a meeting. A focused meeting with an agenda can deal with several points at once (see meeting HMRC in an enquiry).
Ask for a partial closure notice on issues that are already resolved (see partial closure notices).
Use alternative dispute resolution. HMRC’s guidance says ADR can be used where progress in an enquiry has stalled, but not for complaints about HMRC delay.
Apply to the tribunal for a closure notice. Under section 28A(4), or paragraph 33 of Schedule 18 for a company, the taxpayer can apply at any time. The tribunal must direct HMRC to close the enquiry within a set period unless HMRC shows reasonable grounds for not doing so. EM1984 notes that some agents apply routinely once a period, perhaps a month, has passed after records were supplied without a substantive reply.
Complain about delay. Delay is a service issue, handled through HMRC’s complaints process and then the Adjudicator (see HMRC complaints and the Adjudicator).

What does a long enquiry cost?

Professional fees grow with every round of correspondence. If tax turns out to be due, late payment interest runs throughout. EM1813 says that where HMRC anticipates delay and has already identified likely errors, the officer must remind the taxpayer that interest is accruing and invite a payment on account (see paying HMRC during an enquiry). Cooperation also affects penalties: HMRC’s factsheet CC/FS1a says helping with the check allows it to be completed quickly and can reduce any penalty.

What might the timeline look like?

Illustration only. A sole trader’s return is opened for an aspect enquiry into a large repairs claim. The opening letter allows 30 days. The adviser sends invoices and an explanation within three weeks. The officer replies three weeks later asking whether one invoice relates to an extension; the adviser confirms it does and agrees to treat it as capital. The officer issues a closure notice amending the return a few weeks later. By contrast, if the same trader’s cash takings were questioned in a full enquiry, the records review, a meeting, a business economics exercise and penalty negotiations could easily add many months.

What mistakes make enquiries longer?

Sending information in instalments instead of one complete reply.
Letting deadlines pass without asking for more time, which can lead to a formal notice.
Assuming that because nothing has been heard for months, the enquiry has lapsed. It has not until a closure notice is issued.
Waiting for HMRC rather than asking for a timetable or applying for closure.
Treating a VAT check like an income tax enquiry and expecting a closure notice.

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Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 24 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.