You recently received a letter from HMRC querying one of the figures on an earlier tax return. The normal deadline for such enquiries was 31 January 2025. Can you simply ignore HMRC’s questions?
Tax enquiries
Soon after self-assessment was introduced the rules for tax enquiries were overhauled. They allow HMRC sufficient time to raise questions about a tax return while preventing it from having an open-ended right. On the face of it the rules seem clear but below the surface they get decidedly trickier.
Changing deadlines
In the early days of self-assessment the deadline for HMRC starting a tax enquiry if you submitted your tax return at any time up to and including the normal filing date of 31 January, was 31 January the following year. Many people are unaware that this changed in 2008. The basic deadline for HMRC to start an enquiry is now twelve months from the date you submitted your tax return. For example if you submitted your 2022/23 return on 20 January 2024, if HMRC wants to start an enquiry it must have notified you by no later than 19 January 2025.
Tip. If the letter informing you of an enquiry arrives after the deadline, even if it is dated earlier, HMRC has missed the enquiry boat. You should immediately contact the HMRC office that issued it, initially by phone and then in writing to confirm the deadline was missed. HMRC has an internal procedure for checking the timing of enquiry notices which should identify if a tax inspector has left it too near the deadline to ensure timely delivery, or there were other reasons that corroborate your story.
Late tax returns and amendments
The enquiry deadline is different where you submitted your tax return or amended it after the normal filing deadline.
Late returns. If you submit your self-assessment return after the normal filing date, the enquiry window is longer than twelve months. It is twelve months from the end of the quarter in which you submitted your tax return. The quarter days are 31 January, 30 April and so on. For example, if you submitted your 2023/24 tax return on 1 May 2025, HMRC has until 31 July 2026 in which to start an enquiry.
Amended returns. The tax enquiry deadline is also extended to give HMRC a fair chance to enquire into amended figures. Without the extension you could amend your tax return after the normal enquiry deadline had passed which would give HMRC no way to challenge it unless it could use the “discovery” rules to issue an assessment. The enquiry deadline for amendments is therefore twelve months from the end of the quarter in which you submitted your tax return.
Tip. HMRC can only enquire into the amendment, not any other aspect of your tax return, once the normal enquiry deadline has passed.
Example. Gerry submitted his 2023/24 tax return on 1 July 2024. The normal enquiry deadline ended on 30 June 2025. But Gerry amended one entry on his tax return on 1 January 2025. HMRC can start an enquiry into the amendment up to 31 January 2026, but cannot enquire into any other figures on the tax return unless they directly relate to the amended figure.
This article has been reproduced by kind permission of Indicator – FL Memo Ltd. For details of their tax-saving products please visit www.indicator-flm.co.uk or call 01233 653500.