Yes, both can be due because they cover different years. Your 2025/26 online Self Assessment return is normally due on 31 January 2027. Your 2026/27 MTD updates relate to the following tax year, whose annual return is due on 31 January 2028.
Put both years on one timeline
| Work | Period | Usual online annual deadline |
|---|---|---|
| Earlier Self Assessment return | 6 April 2025 to 5 April 2026 | 31 January 2027 |
| MTD digital records and updates, then annual return | 6 April 2026 to 5 April 2027 | 31 January 2028 |
The MTD annual deadline does not move the earlier return into 2028. Specific HMRC notices can affect filing dates, so keep them with the relevant year.
What to label before sending documents
Use a separate folder for each tax year and income source. A statement downloaded in October 2026 might cover 2025/26; its download date does not decide the tax year. Give the accountant the actual transaction or statement dates where anything crosses the boundary.
Check which year your package covers
A plan including the annual return for your MTD service year does not automatically include the previous year’s separate return. Ask TaxSimba to identify both jobs and the fees. If two firms are involved, write down who finishes 2025/26 and who handles 2026/27.
Evidence that each job is done
Keep separate submission confirmations. A completed MTD update is not proof that the earlier Self Assessment return has been filed. Keep tax-payment evidence separately too: filing the figures and paying the amount due are different actions.
Keep two document requests separate
If the accountant asks for your 2025/26 P60 while also checking 2026/27 business records, both requests can be correct. Reply with the tax year in each filename and message. For example, label an employment document “P60 2025-26” and the current trade export “Trade records 6 April to 5 October 2026”.
Before approving anything, ask: which year does this submission finish? Keep a small tracker with one line for the earlier return and another for each current MTD business. A completed item in one line does not close the others.
Two tax years on the same desk
Illustrative example.
In autumn 2026, a taxpayer can be preparing the annual return for 6 April 2025 to 5 April 2026 while maintaining MTD records for 2026/27. A folder called “this year” makes it easy to mix them up.
Label documents with explicit start and end dates. Give the accountant an employment certificate for the earlier return and a separate current-year transaction export for MTD work. Completing one task does not establish that the other has been filed. Check each reporting obligation and its evidence independently.
| Check | Practical action |
|---|---|
| 2025/26 return records | Use income and expense evidence for that tax year. |
| 2026/27 MTD records | Maintain the current-year digital records and update history. |
| Submission evidence | Keep a separate confirmation for each return or update. |
Does a current MTD update finish the earlier return?
No. It covers a different reporting task and period. Confirm the earlier return position separately.
Can one accountant handle both?
Potentially, if the engagement covers both jobs and the accountant has the appropriate authority. Confirm the years and tasks in writing.
Download a checklist for this guide
- 2025/26 annual return status
- 2025/26 missing documents
- 2026/27 businesses and digital records
- 2026/27 update confirmations
- Separate owners and deadlines for both workflows