Self Assessment on 31 January, MTD on 7 February: a winter plan for practices
Self Assessment for 2025/26 is due on Sunday 31 January 2027. The third quarterly update for Making Tax Digital for Income Tax is due on Sunday 7 February. For the first time, both land on the same clients, a week apart.
6 min read · For UK accountancy practices
Our founder Daniel Stachowiak set out the case on AccountingWEB this week: Two Sundays in a row: why January's chase has to start in November. This post is the practical version: what's due, which clients to start with, and a timetable you can copy.
What's due this winter
| Date | What | Who |
|---|---|---|
| Tue 24 Nov 2026 | HMRC late payment interest rises to 8% (base rate 4% plus 4%) | Clients paying Self Assessment late |
| Wed 30 Dec 2026 | Last date to file online and have a balance under £3,000 collected through the tax code | Clients already paying through PAYE |
| Sun 31 Jan 2027 | 2025/26 return, balancing payment and first payment on account for 2026/27 | All Self Assessment clients, including the first MTD cohort |
| Sun 7 Feb 2027 | Third MTD quarterly update, covering 6 April 2026 to 5 January 2027 | Sole traders and landlords with qualifying income over £50,000 |
| Tue 6 Apr 2027 | MTD for Income Tax starts for qualifying income over £30,000, judged on the 2025/26 return | The next cohort |
Both main deadlines fall on a Sunday. In practice, your deadlines are the Fridays before.
Why the January return matters more than usual
HMRC decides who joins MTD at £30,000 from April 2027 using qualifying income on the 2025/26 return. Its guidance says it reviews each return and writes to people over the threshold. A borderline client who files on 31 January may get that letter in February or March, only weeks before their first MTD year begins.
So the order you file in matters. File the clients close to £30,000 first and you can agree software, records and a fee for quarterly work before HMRC writes, not after.
Step 1: split the client list into three
- First MTD cohort: a 2025/26 return by 31 January and a quarterly update by 7 February. Two deadlines, one set of records requests.
- Possible £30k clients: landlords after a rent review, sole traders who had a good year. The return decides whether they join MTD in April. File these first.
- Everyone else: the usual Self Assessment run, with an earlier records date than last year.
Step 2: send one records request, not two
For first-cohort clients, ask once for everything: what you need for the 2025/26 return, and how the October to January records for the quarterly update will reach you. List each item by name: bank statements for each account, sales invoices, expense receipts, and for landlords the agent statements and repair invoices.
Give one return date, and make it early December. Clients plan around the date you give them, not the date HMRC gives you.
Step 3: put reminders on fixed dates
Most of the January rush comes from records that arrive late or half complete, not from the tax work. A reminder that goes out every week until the records are in does more than a phone call in mid-January. Chase only what is still missing, item by item, so clients who have sent most of it aren't asked for everything again.
Step 4: use the money dates to get records in
- Give every client their January figure by mid-December, so they can budget for the balancing payment and the first payment on account.
- Tell PAYE clients who may owe under £3,000 about 30 December: file online by then and HMRC can collect it through their tax code instead of a lump sum in January.
- Mention the interest rate. At 8%, "I'll pay in February" now costs real money, and that is a good reason to send records in November.
Step 5: keep the first week of February clear
The third quarterly update closes on 5 January, so its records arrive in exactly the weeks you are finishing returns. Block out 1 to 7 February in the diary now, so the update isn't squeezed into whatever time is left after 31 January.
There are no penalty points for late quarterly updates in 2026/27, but each update must still be sent before the 2026/27 return can be filed, and the points regime starts in 2027/28. Treat 7 February as the rehearsal.
A timetable you can copy
| When | What to do |
|---|---|
| Mid-November | Split the list into three. Send one records request to each client with a return date in early December. |
| Late November | Weekly reminders start. Chase only the missing items. |
| Early December | File the possible £30k clients first, then talk to them about MTD and quarterly fees. |
| Mid-December | Send every client their January figure. Flag 30 December to PAYE clients owing under £3,000. |
| Early January | Ask first-cohort clients for records to 5 January for the quarterly update. |
| By Fri 29 Jan | Remaining returns filed. |
| 1 to 5 Feb | Third quarterly updates submitted before the Sunday deadline. |
These dates are our suggestions, not HMRC rules. Adjust them to your client mix.
Where MyDocSafe fits
If you'd like one place to send the request, collect the files and run the weekly reminders, MyDocSafe client portals do that for UK practices. The plan above works whatever tools you use.
Frequently asked questions
When is the Self Assessment deadline for 2025/26?
11:59pm on Sunday 31 January 2027, for online returns and for the balancing payment and first payment on account for 2026/27.
When is the third MTD for Income Tax quarterly update due?
Sunday 7 February 2027. It covers 6 April 2026 to 5 January 2027, and updates are cumulative.
Do first-cohort MTD clients still file a 2025/26 tax return?
Yes. Clients who joined MTD for Income Tax in April 2026 still file their 2025/26 return the usual way by 31 January 2027.
How does HMRC decide who joins MTD at £30,000 in April 2027?
It uses qualifying income on the 2025/26 return. HMRC says it reviews each return and writes to people who are over the threshold.
Can a client pay their tax bill through their tax code?
Yes, if they owe less than £3,000, already pay tax through PAYE and file their return online by 30 December 2026.
