When HMRC misses the 45 day review deadline

Q: How might the dates work?

Illustration only. HMRC's Legal Group receives Priya's acceptance of a review of her income tax closure notice on 1 June. The 45 days begin that day and end on 15 July. No conclusion arrives. On 16 July the review officer phones to ask for another month; Priya declines because her adviser is ready to go to the tribunal. HMRC writes on 22 July saying the review is treated as having upheld its view. Priya can notify her appeal to the tribunal from 16 July, and the window ends 30 days after 22 July, on 21 August. If she misses that date, the deemed conclusion settles the appeal unless the tribunal gives permission to appeal late.

If HMRC does not send its review conclusions within 45 days, or within a longer period you have agreed, the law treats the review as having upheld HMRC’s position and HMRC must write to tell you so. You can then go to the tax tribunal at any time from the day after the review period ends until 30 days after the date of that letter. If you do nothing, the deemed conclusion settles the dispute in the same way as a real one.

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When does the 45 day review period start?

The start date depends on how the review began. For direct taxes, section 49E(7) of the Taxes Management Act 1970 says the period runs from the day HMRC received your acceptance of its offer, or, where you required the review, from the day HMRC notified you of its view of the matter. For VAT, section 83F(7) of the Value Added Tax Act 1994 uses the date HMRC received your acceptance, the date it received a third party’s request, or, for a review accepted late, the date HMRC decided to carry it out. ARTG4690 applies the same rules, including to late acceptances of direct tax reviews.

Under sections 49E(6) and 83F(6), HMRC must notify its conclusions and its reasoning within 45 days beginning with that date, or within such other period as is agreed with you. Because the period begins with the start date, that day counts as day one.

Can HMRC extend the deadline on its own?

No. The only alternative to 45 days in the legislation is a period agreed with you. ARTG4620 tells review officers to estimate early how long a review will take and, if more time is likely to be needed, to seek your agreement at the start rather than towards the end, though not as a matter of course. It adds that if you do not agree, the review must be completed within the 45 days.

ARTG4850 sets out what happens when a review officer is about to run out of time. They should contact you, by phone if possible, to negotiate an extension, and then confirm the agreed new deadline in writing. An extension has to be agreed by you; silence is not agreement.

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What happens if the deadline passes without agreement?

Section 49E(8) for direct taxes and section 83F(8) for VAT treat the review as having concluded that HMRC’s view, or the decision, is upheld. Sections 49E(9) and 83F(9) then require HMRC to notify you of the conclusion the review is treated as having reached. ARTG4850 says the review officer must stop work on the review and write telling you that the decision is treated as upheld and that you have the right to go to the tribunal within 30 days of that letter. The letter must go to you directly, with a copy to your agent.

A deemed conclusion is not a reasoned one. You will not get the review officer’s analysis of your arguments, which is one of the main benefits of a completed review.

When can you then appeal to the tribunal?

The window opens the day after the review period ends. For direct taxes, section 49G(5)(b) defines the post review period as beginning with the day after the last day of the 45 days, or agreed period, and ending 30 days after the date of the document in which HMRC gives notice under section 49E(9). For VAT, section 83G(5) allows an appeal at any time from the end of the review period to the date 30 days after the conclusion date, meaning the date of the document notifying the conclusion. ARTG2420 and ARTG3120 describe the same windows.

You do not have to wait for HMRC’s letter: once the period has expired you can notify the appeal. After the window closes, the tribunal’s permission is needed (section 49G(3) and section 83G(6)). See lodging a notice of appeal at the tax tribunal for the form and contents.

What if you do nothing after the deemed conclusion?

For direct taxes, section 49F applies to conclusions notified under section 49E(9) just as it does to a completed review. The conclusion is treated as a written agreement settling the matter under section 54(1), and you cannot resile from it, unless you notify the appeal to the tribunal under section 49G. For indirect taxes, ARTG3120 says that if you do not appeal within the time allowed the dispute is resolved in line with the review conclusions, subject to the tribunal accepting a late appeal. Our guide to settling an appeal by agreement explains why a section 54 settlement is so hard to reopen.

Should you agree to give HMRC more time?

Often it is sensible, but weigh it up. A completed review can vary or cancel the decision, saving you a tribunal appeal, and HMRC’s guidance says new information or specialist advice are common reasons for needing longer. Against that:

Interest. GOV.UK warns that interest can be charged on disputed tax until it is paid, so delay costs money if you lose.
Waiting. ARTG4850 says that if you agree to an extension after the review period has already expired, you cannot go to the tribunal until the agreed period ends or the review is completed, whichever is earlier.
Payment for VAT. Disputed indirect tax is not collected during a review, but ARTG4680 says the suspension is removed at the end, and a tribunal appeal then usually requires payment or a successful hardship application. See the VAT pay first rule.
No second chance. ARTG4860 says you are entitled to only one review, even if you provide new information.

If you do agree, confirm the new end date in writing so that both sides count from the same day.

How might the dates work?

Illustration only. HMRC’s Legal Group receives Priya’s acceptance of a review of her income tax closure notice on 1 June. The 45 days begin that day and end on 15 July. No conclusion arrives. On 16 July the review officer phones to ask for another month; Priya declines because her adviser is ready to go to the tribunal. HMRC writes on 22 July saying the review is treated as having upheld its view. Priya can notify her appeal to the tribunal from 16 July, and the window ends 30 days after 22 July, on 21 August. If she misses that date, the deemed conclusion settles the appeal unless the tribunal gives permission to appeal late.

What mistakes come up most often?

Waiting indefinitely for a late conclusion letter. Once the 45 days end, the review is treated as upheld.
Assuming HMRC can extend the period by telling you it needs longer. It needs your agreement.
Agreeing an extension by phone without a written note of the new end date.
Counting the tribunal deadline from the end of the 45 days instead of from the date of HMRC’s notice of the deemed conclusion.
Treating a deemed upheld conclusion as less binding than a real one. Without a tribunal appeal it settles the dispute. If the delay itself caused problems, see complaint or appeal.

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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.