Last updated: 28 August 2026
The Self Assessment deadline most UK practices are working to right now is 31 January 2027. That is the online filing deadline and the payment deadline for the 2025/26 tax year, which ran from 6 April 2025 to 5 April 2026. The 2026/27 tax year is a different animal. It began on 6 April 2026, its return is not due until 31 January 2028, and for clients inside Making Tax Digital for Income Tax it carries four quarterly update deadlines along the way: 7 August 2026, 7 November 2026, 7 February 2027 and 7 May 2027. That third one lands seven days after the January filing peak. It is the single reason the coming season will not feel like any January your practice has worked before.
Most guides to the Self Assessment deadline are written for the taxpayer. This one is written for the practice that files on their behalf, because the operational problem in January was never understanding the date. It was absorbing roughly half a year of compliance work into four weeks with the same team you had in September.
I have spent the last two years talking to principals about exactly this, most recently across two days at Accountex London. Almost nobody opened the conversation with cost. They opened with capacity. Below is the full deadline and penalty picture for 2026/27, verified against HMRC guidance at the time of writing, followed by what the January volume actually looks like in the data and how firms are structuring around it.
Key takeaways
- Two tax years are live at once. The 2025/26 return is due by 31 January 2027 under the old rules. The 2026/27 year is already running under MTD for Income Tax for clients above the £50,000 threshold.
- The January 2027 peak now has a tail. The Q3 MTD quarterly update deadline of 7 February 2027 sits seven days after 31 January. There is no recovery week.
- Filing penalties and payment penalties run on separate clocks. A client can be hit by both at once, and the £100 fixed filing penalty applies even where no tax is owed.
- Late payment interest is 7.75%. That is the Bank of England base rate plus four percentage points, in effect since 9 January 2026, charged daily from 1 February.
- Nearly half the annual filing volume arrives in the final four weeks. HMRC recorded 6.36 million returns filed by early January 2026 with 5.65 million still outstanding.
- MTD sign up is incomplete and HMRC is closing the gap. Of 864,000 taxpayers in the first phase, 436,000 had filed a first quarterly update by mid August 2026. HMRC began signing up the remainder from September.
- Capacity is a planning number, not a feeling. The compression test set out below turns January into arithmetic you can run in ten minutes.
What is the Self Assessment deadline for the 2026/27 tax year?
The Self Assessment deadline for the 2026/27 tax year is 31 January 2028 for online filing and for paying any balance owed. The 2026/27 tax year runs from 6 April 2026 to 5 April 2027, and the filing deadline always falls on the 31 January that follows the end of the tax year.
This trips people up constantly, including in published guidance. A large number of pages currently answering the query “self assessment deadline 2026/27” give the answer 31 January 2027. That date is real, but it belongs to the 2025/26 return. If you are briefing a client or writing a deadline reminder, the distinction matters, because getting it wrong by one year moves a payment obligation by twelve months.
For clients mandated into MTD for Income Tax from 6 April 2026, the 2026/27 obligation is not a tax return in the old sense at all. It is four quarterly updates followed by a final declaration, and the final declaration is the thing due on 31 January 2028. Our MTD for Income Tax readiness guide sets out who is in scope and how the qualifying income test is applied.
Which return are you actually filing in January 2027?
In January 2027 you are filing the 2025/26 return, under the existing Self Assessment rules, for every client who needs one. That includes clients who have already joined MTD for Income Tax, because MTD applies from 6 April 2026 and the 2025/26 year sits entirely before that date. HMRC has confirmed that current penalties apply to the 2025/26 return even for taxpayers who joined MTD in April 2026.
The table below is the one to put in front of a client who is confused about which obligation is which.
| Obligation | 2025/26 tax year | 2026/27 tax year |
|---|---|---|
| Tax year runs | 6 April 2025 to 5 April 2026 | 6 April 2026 to 5 April 2027 |
| Reporting system | Self Assessment (SA100) | Self Assessment, or MTD for Income Tax if mandated |
| Register if new | 5 October 2026 | 5 October 2027 |
| Paper return | 31 October 2026 | 31 October 2027 (not available to MTD filers) |
| Quarterly updates | None | 7 Aug 2026, 7 Nov 2026, 7 Feb 2027, 7 May 2027 |
| Online return or final declaration | 31 January 2027 | 31 January 2028 |
| Balancing payment | 31 January 2027 | 31 January 2028 |
| Payments on account | 31 January 2027 and 31 July 2027 | 31 January 2028 and 31 July 2028 |
The practical consequence is that a mandated client has obligations under both systems in the same twelve month window. They file a 2025/26 SA100 by 31 January 2027 and, one week later, a Q3 quarterly update for 2026/27. Neither replaces the other.
What are the full Self Assessment deadlines for the 2025/26 return?
Five dates carry consequences for the 2025/26 return, and one of them, 30 December 2026, is routinely missed because nothing bad happens immediately when you skip it.
| Date | What is due | What happens if it slips |
|---|---|---|
| 5 October 2026 | Register for Self Assessment if the client is new to it | Failure to notify penalty, calculated on the potential lost revenue |
| 31 October 2026 | Paper return must reach HMRC | Return is treated as late unless filed online by 31 January 2027 |
| 30 December 2026 | File online if the client wants a balance under £3,000 collected through their 2027/28 PAYE code | No penalty, but the client loses a twelve month interest free spread and must pay in full on 31 January |
| 31 January 2027 | Online return, balancing payment for 2025/26, first payment on account for 2026/27 | Two separate penalty tracks start, one for the return and one for the money |
| 31 July 2027 | Second payment on account for 2026/27 | Interest accrues from 1 August, though the 5% surcharges do not apply to payments on account |
The 30 December date is worth a proactive email campaign in November. For a client with a £2,400 balance, coding out spreads the cost across twelve monthly pay packets instead of landing in one January payment. It costs your practice one earlier filing slot and removes a cash flow conversation you would otherwise have in the last week of January, which is the most expensive week of your year to spend on cash flow conversations.
A fuller month by month view of every UK filing obligation sits in our UK tax year 2026/27 key dates calendar.
What are the MTD for Income Tax deadlines for 2026/27?
MTD for Income Tax became mandatory on 6 April 2026 for sole traders and landlords whose qualifying income exceeded £50,000, measured on their 2024/25 Self Assessment return. Qualifying income is gross turnover from self employment and UK or foreign property combined, before expenses or allowances. Employment income, pensions, dividends, interest and capital gains do not count towards it.
| Period covered (standard quarters) | Submission deadline | Notes |
|---|---|---|
| 6 April 2026 to 5 July 2026 | 7 August 2026 | First update. Cumulative from 6 April |
| 6 April 2026 to 5 October 2026 | 7 November 2026 | Cumulative, not just the second quarter |
| 6 April 2026 to 5 January 2027 | 7 February 2027 | Falls seven days after the 31 January peak |
| 6 April 2026 to 5 April 2027 | 7 May 2027 | Final quarterly update for the year |
| Whole of 2026/27 | 31 January 2028 | Final declaration and balancing payment |
Three features of this regime change how a practice schedules work. First, updates are cumulative, so an error in Q1 is corrected in Q2 rather than amended separately. Second, clients can elect calendar quarters (1 April to 30 June and so on) instead of tax year quarters, which suits anyone drawing accounts to 31 March, but the election must be made in the software per income source before the first update and cannot be changed mid year. Third, and most importantly for workflow, all four quarterly updates must be submitted before the final declaration can be filed. A client who quietly skipped Q2 does not discover the problem in November. They discover it in January 2028, when you cannot file.
If you are still deciding how to run submissions at volume, the comparison in our MTD for Income Tax software guide for accountants covers bulk submission, client status dashboards and agent authorisation handling.
What are the late filing penalties if a client misses 31 January?
HMRC charges an automatic £100 penalty the day a Self Assessment return is late, and it applies even where the client owes no tax at all. The charges escalate on a fixed ladder from there. For the 2025/26 return filed after 31 January 2027, the ladder is as follows.
| How late | Penalty | Running total on a nil liability |
|---|---|---|
| 1 day | £100 fixed, regardless of tax owed | £100 |
| 3 months | £10 per day for up to 90 days | £1,000 |
| 6 months | The greater of £300 or 5% of the tax due | £1,300 |
| 12 months | A further £300 or 5% of the tax due. Up to 100% of the tax where the failure is deliberate and concealed | £1,600 |
The nil liability column is the one clients find hardest to believe. A dormant sole trader with no profit and no tax to pay can still accumulate £1,600 in penalties purely for not filing, because the filing ladder is triggered by lateness, not by liability. It is the single most useful figure to put in a chaser email in early January.
HMRC estimated that around one million taxpayers missed the 31 January 2026 deadline, against 11,489,825 returns received and 12,029,168 expected. That is a stable annual pattern rather than a bad year, and the Low Incomes Tax Reform Group guidance on missed deadlines is a good plain English resource to send clients who fall into it.
What does HMRC charge for paying late, and how much is interest?
Paying late costs a client two separate things: percentage surcharges and daily interest. They are calculated independently and both apply.
The surcharges are 5% of the tax still unpaid at 30 days after the due date, a further 5% at six months, and another 5% at twelve months. Each one is calculated on whatever remains outstanding at that moment, so a part payment before each trigger date reduces every later charge. Clearing half the balance before the six month point halves both the six month and twelve month surcharges.
Interest runs on top. The current late payment rate is 7.75% a year, set at the Bank of England base rate plus four percentage points and in effect since 9 January 2026, per the HMRC interest rates for late and early payments. It is simple interest, charged daily from the day after the due date, with no grace days for weekends or bank holidays. The margin rose from base rate plus 2.5% on 6 April 2025, which means paying HMRC late is materially more expensive than it was two seasons ago. Repayment interest, what HMRC pays when it owes the client, sits at 2.75%, so the spread between what a client pays HMRC and what HMRC pays a client is five percentage points.
The rate has been stable for eight months and is likely to stay that way into the filing season. The Monetary Policy Committee held Bank Rate at 3.75% on 30 July 2026, having last cut it in December 2025, and the next scheduled decision is 17 September 2026. If it moves, HMRC normally follows within a few weeks. The table below is the arithmetic so you do not have to redo it, showing the resulting HMRC rate and the daily interest cost per £10,000 of unpaid tax.
| If Bank Rate is | HMRC late payment interest | Daily cost per £10,000 unpaid |
|---|---|---|
| 3.25% | 7.25% | £1.99 |
| 3.50% | 7.50% | £2.05 |
| 3.75% (held on 30 July 2026) | 7.75% | £2.12 |
| 4.00% | 8.00% | £2.19 |
| 4.25% | 8.25% | £2.26 |
One nuance worth knowing: the 5% surcharges apply to the 31 January balancing payment but not to payments on account. A missed 31 July instalment attracts interest only. That does not make it free, and it is not a reason to advise a client to deprioritise it, but it does change the ranking when a client can only pay one of two things.
The size of the balancing payment itself follows from the 2026/27 income tax rates and personal allowances, which is worth checking before you tell a client what to expect in January. Where a client genuinely cannot pay, a Time to Pay arrangement usually prevents the first 5% surcharge if it is agreed before the 30 day point. Self Assessment liabilities up to £30,000 can be set up online without calling HMRC, a threshold raised from £10,000 in October 2020. Interest continues to accrue on the outstanding balance either way.
What does a missed deadline actually cost a client?
Nobody acts on a penalty ladder. They act on a number. So here are three client positions worked through in full, using the published 2025/26 rates and the 7.75% interest rate, on the assumption the return relates to 2025/26 and the deadline missed is 31 January 2027. Every figure is arithmetic from HMRC’s own charges, not an estimate.
| Client position | Filing penalties | Payment penalties and interest | Total cost |
|---|---|---|---|
| Dormant sole trader, no tax due, return filed 12 months late | £100 + £900 + £300 + £300 = £1,600 | Nil, because there is no tax to pay late | About £1,600 |
| £4,000 balance, return and payment both six months late | £100 + £900 + £300 = £1,300 | £200 + £200 surcharges, plus about £155 interest | About £1,855, which is 46% of the bill |
| £18,000 balance, return filed on time, payment six months late | Nil | £900 + £900 surcharges, plus about £696 interest | About £2,496, which is 14% of the bill |
Compare rows two and three and the single most useful piece of client advice falls out of the table. The client with the £18,000 bill owed four and a half times as much tax, was equally late paying it, and paid a smaller share of the liability in charges, purely because the return went in on time. Filing on time while unable to pay removes the entire £1,300 filing ladder and leaves only the payment charges, which a Time to Pay arrangement can then reduce further.
Put plainly: file, even when the client cannot pay. It is the cheapest intervention available in January and it is the one clients resist most, because they assume the two obligations are linked. They are not. The return and the money run on separate clocks, and only one of them is free to stop.
How do the new points based penalties work for MTD clients?
The points regime replaces fixed penalties with a driving licence style system. A taxpayer receives one penalty point for each missed submission deadline, and once they reach four points they receive a £200 penalty, plus a further £200 for every subsequent late submission. Only one point is given per deadline, even where a client runs several businesses and files multiple quarterly updates.
For 2026/27 there is a soft landing, and it is narrower than most clients assume. HMRC will not issue penalty points for late quarterly updates in the 2026/27 tax year. That is the whole of the concession. It does not cover the final declaration due on 31 January 2028, it does not cover late payment penalties or interest, and it does not remove the obligation itself, because the updates must still be filed before the return can be submitted. From 6 April 2027 the points regime applies to quarterly updates in full, and anyone joining in a later phase gets no grace year at all. The detail is set out in the GOV.UK guidance on penalties for Making Tax Digital for Income Tax and in the LITRG explainer on MTD penalties.
My honest view is that the soft landing is doing more harm than good in some practices, because it has been read as permission to defer the operational build for a year. The clients who drift through 2026/27 without a working record keeping habit are the ones who will collect four points quickly in 2027/28, and by then the threshold drops to £30,000 and the population in scope grows again.
Why will January 2027 be harder for practices than January 2026?
Because for the first time, the peak has a tail attached. The 31 January 2027 filing deadline is followed seven days later by the 7 February 2027 quarterly update deadline for every mandated client. In every previous cycle, the first week of February was recovery time. In 2027 it is a second deadline for a population of 864,000 taxpayers, a meaningful share of whom sit on practice client lists.
Three further pressures compound it.
- MTD sign up is incomplete. HMRC reported that 436,000 sole traders and landlords had filed a first quarterly update by mid August 2026, with more than 570,000 signed up, out of 864,000 expected to be in scope. The gap is not small, and it is not evenly distributed across practices.
- HMRC started closing the gap in September. From September 2026, HMRC began signing up customers who need to use MTD for Income Tax for 2026/27 but had not done so themselves. Those clients receive a letter, and the letter usually arrives on your desk rather than theirs.
- Q3 covers the Christmas period. The quarterly update due on 7 February 2027 is cumulative to 5 January 2027, so the underlying bookkeeping has to be complete for a period that includes the two weeks of the year when client responsiveness is at its lowest.
None of this is a reason to panic. It is a reason to move the record request cycle earlier by about three weeks and to treat the mandated cohort as a separate workflow rather than folding it into the general January list.
Where does January volume actually concentrate?
The volume is not spread across January. It is stacked at the end of it, and HMRC publishes enough data each year to see the shape precisely.
For the 2024/25 returns due on 31 January 2026, HMRC reported that more than 6.36 million taxpayers had filed by the start of January, leaving almost 5.65 million still to complete. In other words, with roughly 8% of the filing window remaining, about 47% of the work had not been done. For the previous year, HMRC recorded 732,498 returns filed on deadline day itself, including 31,442 in the final hour between 23:00 and midnight.
| Filing checkpoint | Figure | What it tells a practice |
|---|---|---|
| Returns expected for 2024/25 | 12,029,168 | The denominator for planning, stable year on year |
| Filed by early January 2026 | 6.36 million | Just over half the work done with one month left |
| Still outstanding at that point | 5.65 million | The real January workload across the profession |
| Filed by the deadline | 11,489,825 | Around 5.1 million returns filed inside the final four weeks |
| Estimated to have missed it | About 1 million | Roughly £100 million in fixed penalties before the ladder starts |
Read that as a workload distribution rather than as client behaviour and it changes the planning question. The profession is not slow. The profession is structurally asked to deliver something close to half its annual compliance output inside four weeks, and the record request cycle is the only variable a practice fully controls.
The wellbeing cost is documented. caba, the occupational charity for ICAEW members, reports that 56% of accountants have experienced burnout against 41% of employees in other sectors, with heavy workloads and tight deadlines identified as the primary drivers.
How much January capacity does your practice actually need?
Most practices estimate January by feel, then discover the gap in the third week when it is too late to do anything about it except work weekends. Here is a five step arithmetic test that takes about ten minutes and produces a number you can act on in October. We call it the compression test, and it deliberately uses your figures rather than industry averages, because average turnaround times across firms are close to meaningless when the variable that matters is your own review bottleneck.
- Step 1. Count the returns still open on 1 December. Not total clients. Open files with no complete record set. Last year’s number is a fair proxy if you have not started tracking it.
- Step 2. Multiply by your true average preparation time. Take the total hours booked to personal tax last January and divide by the returns filed in that month. This gives you a blended figure that already includes chasing, rework and query handling, which a per return estimate never does.
- Step 3. Add review time separately. Review is the bottleneck, not preparation, because it sits with the smallest number of people. Count reviewer hours per return and the number of people qualified to sign off.
- Step 4. Calculate available hours, not headcount. Working days in January, minus holiday, minus the days lost to client meetings and admin, multiplied by realistic productive hours per person. Six is honest. Eight is not.
- Step 5. Compare, then look at the reviewer line on its own. If total capacity clears but reviewer capacity does not, adding preparation resource makes the queue longer, not shorter. That is the most common and most expensive misdiagnosis in January. The same bottleneck logic applies at company year end, which our note on year end accounting bottlenecks works through.
The output is one of three positions. You have enough capacity and a scheduling problem. You have a preparation shortfall, which is solvable with additional resource. Or you have a review shortfall, which is not solvable by adding juniors and needs either a qualified reviewer or a genuine reduction in the number of files reaching review in the final fortnight.
Run it in October and the answer is still actionable. Run it on 10 January and you are choosing between overtime and turning work away. Wolters Kluwer research on firm responses to workload surges found that more than half of surveyed firms added remote or outsourced help and 70% increased hours for existing staff, which tells you how the profession currently resolves the gap and why the same gap reappears the following year.
How do practices handle January volume without breaking the team?
Six levers move the number. They are listed roughly in order of how much work they take to implement, cheapest first.
- Move the record request cycle to September. Not October. September, so that the second chaser lands before the Q2 MTD deadline on 7 November rather than competing with it. Use the same pass to check agent authorisation is in place for every file, because a missing 64-8 or an MTD client who has not authorised your Agent Services Account is a blocker you cannot solve in the final week. A request sent in September and chased twice converts far better than one sent in November and chased four times.
- Segment the client list before you start. Split into files that can be prepared from bank feed and software data alone, including anyone still waiting on a UTR from a late registration, files needing one specific document, and files needing a conversation. The three groups need different chasers, different owners and different deadlines. Treating them as one list is what produces the last week pile up.
- Run the coding out campaign in November. Every client with an expected balance under £3,000 who files by 30 December gets a twelve month interest free spread through their PAYE code. This pulls filings forward and removes January payment conversations at the same time.
- Triage payments on account in December, not February. Where a client’s 2026/27 income is clearly down, an SA303 claim to reduce payments on account is a genuine cash flow intervention. Made in December it is planning, and it sits naturally alongside the wider year end tax planning checklist. Made in February it is damage control, and the interest position is already worse.
- Isolate the MTD cohort into its own workflow. Mandated clients have a 7 February obligation your other clients do not. Give them a separate owner, a separate deadline board and a Q3 record cut off in early January. Folding them into the general list guarantees the update slips.
- Decide the capacity question before December. Overtime, a temporary hire or outsourced preparation are all defensible answers. Deciding in the third week of January is not, because none of the three can be stood up in a fortnight. Our peak season playbook for scaling a practice works through the trade offs, and the outsourced accounting quality control checklist sets out the two stage model, offshore preparation with onshore review and sign off, that keeps the review layer inside the practice.
One thing I would push back on, having watched a lot of firms try it: hiring permanently to solve a four week peak rarely works out. The recruitment market for qualified personal tax staff is difficult enough that the role is often unfilled by December, and the cost sits on the payroll for the other eleven months. The structural view of the accountancy talent shortage is worth reading before committing to a permanent hire as a seasonal fix.
What should the 2026/27 cycle look like month by month?
This is the schedule we would run for a practice with a mixed personal tax and MTD client base. Adapt the volumes, keep the sequence.
| Month | Priority action | Why it sits here |
|---|---|---|
| September 2026 | Issue 2025/26 record requests. Confirm which clients HMRC has auto signed up for MTD | Two clear months before the Q2 update competes for attention |
| October 2026 | Run the compression test. Decide the capacity route. First chaser round | Last month in which added resource can realistically be sourced |
| November 2026 | Q2 MTD update by 7 November. Coding out campaign for balances under £3,000 | The coding out window closes on 30 December and needs lead time |
| December 2026 | File coding out cases by 30 December. Triage payments on account. Set Q3 record cut off | Everything filed here is a file not competing in January |
| January 2027 | Filing and review only. Protect reviewer time. Payment reminders in week two, not week four | Reviewer capacity is the binding constraint from about 15 January |
| February 2027 | Q3 MTD update by 7 February. Then penalty mitigation and appeals for any misses | The 7 February deadline removes the traditional recovery week |
| March to May 2027 | Q4 update by 7 May. Debrief the season with real numbers | A debrief written in May is honest. One written in February is emotional |
How can you reduce a client’s penalty exposure after a miss?
Four routes are worth working through, in this order.
- File immediately, whatever else is unresolved. The daily £10 charges begin three months after the deadline and run for up to 90 days. Filing an estimated return and amending it later stops a clock that an unfiled return leaves running.
- Arrange Time to Pay before day 30. An agreement reached before the 30 day point usually prevents the first 5% surcharge. Balances up to £30,000 can be arranged online. Interest still accrues, so this manages penalties rather than eliminating cost.
- Appeal on reasonable excuse where one genuinely exists. Serious illness, bereavement, a service failure at HMRC and unexpected hospital stays are recognised. Being busy, or having found the return harder than expected, is not, and a weak appeal spends goodwill you may need later.
- Reduce payments on account where the evidence supports it. An SA303 claim lowers the 31 January and 31 July instalments where income has genuinely fallen. Reduce them too far and HMRC charges interest on the shortfall, so the claim needs to be defensible rather than optimistic.
For clients with genuinely complex personal tax positions, where the exposure sits in residence, non UK income or capital gains rather than in lateness, our note on choosing a partner for complex personal tax work sets out what to look for in review quality.
What do practices get wrong about the January deadline?
Three things, consistently.
They treat January as a capacity problem when it is a scheduling problem. The work is knowable from April. What varies is when the practice asks for it. A firm that requests records in September and one that requests them in November do the same volume of work with entirely different amounts of pain, and the difference is almost never staffing.
They add preparation resource to a review bottleneck. If two people can sign off and eight can prepare, adding a ninth preparer lengthens the review queue. This is the misdiagnosis that turns a £6,000 outsourcing spend into no measurable improvement, and it is why the compression test separates the two lines.
They price January work at the same rate as October work. A return delivered complete in October and one delivered incomplete on 25 January are not the same product and should not carry the same fee. Whether you implement that as a late records surcharge or an early filing discount is a positioning choice, and our note on fixed fee versus hourly billing for UK practices works through both. What is not defensible is absorbing the cost silently, which is what most firms do.
One further point, on the £3,000 reporting threshold that keeps appearing in client conversations. The government announced in March 2025 that the Self Assessment reporting threshold for trading income will rise from £1,000 to £3,000, with a simplified online service for those in between. It is not in force, no start date has been confirmed, and published estimates of when it lands range from 2027/28 to 2029/30. The £1,000 trading allowance itself is not changing. Until HMRC confirms a date, the answer to a client asking whether they can stop filing is no. IPSE’s explainer is a reasonable link to send them.
Planning the 2026/27 season
The dates in this guide will not change. The 31 January 2027 filing deadline and the 7 February 2027 quarterly update deadline are both fixed, and the seven days between them is the tightest the UK compliance calendar has ever been for personal tax. What is still open is when your practice asks clients for records, whether you know your reviewer capacity number, and whether the resource decision gets made in October or in the third week of January.
If you want a second view on the capacity maths before you commit to a route, talk to our team. Bring the actual constraint rather than a brief. If outsourcing is not the right answer for your firm, we would rather say so in September than discover it together in February.
Frequently Asked Questions (FAQ)
31 January 2028 for online filing and payment, because the 2026/27 tax year ends on 5 April 2027. The 31 January 2027 deadline that appears in many search results belongs to the 2025/26 return.
Both, for different years. The 2025/26 return is due by 31 January 2027. The 2026/27 return or MTD final declaration is due by 31 January 2028. If someone asks about "this year’s" return in late 2026, they almost always mean 2025/26.
Yes. MTD for Income Tax applies from 6 April 2026, so the 2025/26 year falls entirely under the old rules and the SA100 is due by 31 January 2027 in the normal way. HMRC has confirmed that existing penalties apply to that return even for taxpayers who joined MTD in April 2026.
£100, applied automatically, whether or not any tax is owed. It is not proportionate to the delay and there is no grace period, so a return filed at 00:01 on 1 February carries the same £100 as one filed in March.
7.75% a year, in effect since 9 January 2026, calculated as the Bank of England base rate plus four percentage points. It is simple interest charged daily from the day after the due date, including weekends and bank holidays, and it is separate from the 5% surcharges at 30 days, six months and twelve months.
No. They are cumulative summaries of income and expenses submitted through compatible software, and they create no payment obligation on their own. Payment dates remain 31 January and 31 July. However, all four updates must be submitted before the final declaration can be filed.
No penalty points are issued for late quarterly updates in the 2026/27 tax year under HMRC’s soft landing. The obligation remains, the update must still be filed before the final declaration, and the concession does not extend to the final declaration itself, to late payment penalties, or to any later tax year.
Yes, through two routes. Filing online by 30 December with a balance under £3,000 lets HMRC collect it through the following year’s PAYE code at no interest cost. After that, a Time to Pay arrangement covers balances up to £30,000 online, and agreeing it before day 30 usually avoids the first 5% surcharge, though interest continues to accrue.
September, for the 2026/27 cycle specifically, so the second chaser round lands before the 7 November quarterly update deadline rather than competing with it. HMRC data shows roughly 47% of returns were still outstanding at the start of January 2026, which is a request timing outcome as much as a client behaviour one.
Yes, and it catches practices out. A disposal of UK residential property must be reported and paid through the HMRC property account within 60 days of completion, separately from the annual return. A completion in late November or December therefore produces a 60 day deadline that lands in January or early February, on top of the Self Assessment peak. The gain is then reported again on the SA100. Flagging December completions in your November client review is a two minute check that removes a very expensive surprise.
It reduces preparation pressure. It does not reduce review pressure, because sign off stays with the practice. If your compression test shows the bottleneck sits at review, outsourcing preparation will shorten the queue into review but not the queue out of it, and the capacity plan needs a qualified reviewer as well. Our tax compliance outsourcing service is built around that distinction, and the comparison of UK tax outsourcing providers covers how different models handle the review layer.
