EM1506 - Opening the Enquiry: Statute: ITSA Time Limits
Source: gov.uk (2025-09-04)


TMA70/S9A(2)TMA 70/S12AC(2)

Returns made on or before usual filing date

Testing the Change Notes

Until 31 March 2008 the time limit for opening enquiries into returns received on or before the fixed 31 January filing date was the following 31 January.

Before FA2001 the time limit for opening such enquiries was 30 January.

From 1 April 2008 when a tax return is received on or before the relevant filing deadline, the enquiry window will run for a full 12 months from the date the tax return is received. So for a return received by HMRC on 20 June 2018, the enquiry window will run to 20 June 2019.

The date a voluntary return is received by HMRC is treated as the date a notice requiring the return is given. A voluntary return will always therefore be received on the same date as the notice is given so it will always be made on or before the filing date, which is explained at EM1505 (https://www.gov.uk/hmrc-internal-manuals/enquiry-manual/em1505). The enquiry window will always be 12 months from the date a voluntary return is received.

Late returns

If a return is delivered after the fixed filing date, the enquiry period is extended. The enquiry window will in these cases not close until the quarter day next following the first anniversary of the day on which the return was made.

As a voluntary return will always be made on or before the filing date, it can never be late and the extended enquiry window will not apply.

Amendments

A taxpayer can make an amendment to their return up to 12 months from the filing date, see EM1505 (https://www.gov.uk/hmrc-internal-manuals/enquiry-manual/em1505).

For the 2020-21 tax year, if a notice to file was given, or for a voluntary return treated as given, on or before 31 October 2021, the filing date for the purposes of amending the return is 31 January 2022. A taxpayer can make an amendment to their return up to 31 January 2023.

For the 2020-21 tax year, if a notice to file was given, or for a voluntary return treated as given, on any day after 31 October 2021, the filing date is 3 months later. For example, if this date is 1 November 2021 the filing date for the purposes of amending the return is 1 February 2022. A taxpayer can make an amendment to their return up to 1 February 2023.

The amendment does not change the enquiry period for the return, which is explained above.

There is however a separate enquiry window for the amendment. The enquiry period for the amendment is up to the quarter day next, following the first anniversary of the date that the amendment was made.

The quarter days are 31 January, 30 April, 31 July and 31 October.

If a 2020-21 return was made on 31 January 2022 it could be amended up to 31 January 2023. If it was amended on 2 January 2023, the last date for giving a notice of intention to enquire into the amended return is 31 January 2024.

Receipt of notice and evidence

Your notice must be received before the time limit.

It is important that you retain evidence that the enquiry notice has been posted, just in case the customer challenges receipt of it. For all cases, it is best practice to note on Caseflow/SA the date that the notice left the office. You should also contact the customer and/or agent by telephone to inform them that the notice is on the way. Notes of the calls should be made and retained in the case papers. If you need written authorisation from your manager for the use of first class post or tracked delivery, a copy of the authority should be uploaded to Caseflow and/or also placed in the file as evidence.

This list of evidence is not intended to be exhaustive and you should keep any further evidence that you have of the notice being issued. We should not wait until too near to the last date for the enquiry to issue the notice. In cases where it is unavoidable that the notice is issued within one week of the last date for the enquiry, you should, in addition to retaining the evidence detailed above, ensure that the notice is sent via tracked delivery and evidence of this is retained.

Unless the contrary is proved, the notice is taken to be delivered as it would have been through the ordinary course of post. Royal Mail’s published position is that second class post takes up to 3 working days to be delivered and first class post takes 1 working day. Working days include Saturdays but not Sundays or Bank Holidays.

From 28 July 2025 Royal Mail updated their position for second class post only. They still aim to deliver second class post within 3 weekdays but will only deliver every other weeekday over a two week period. (Weekdays include Mondays - Fridays, but do not include Saturdays, Sundays or Bank Holidays).

You should consider how long the post takes to leave the office when considering this. If you are ever in doubt as to whether a notice will be sent in time using Royal Mail, send it via tracked delivery instead so we have proof of receipt.

This is only a guide and each case will need to be decided on their own facts.

All notices relating to Income Tax, Capital Gains Tax or Corporation Tax enquiries must be in writing, see EM0067 (https://www.gov.uk/hmrc-internal-manuals/enquiry-manual/em0067).