The deadline has passed. File the return today anyway, and pay what you can. Late filing and late payment are billed separately, and both get more expensive the longer you leave them.
For the 2025/26 return the online deadline was 11:59pm on 31 January 2027. Paper was 31 October 2026. If you are reading this in time, the calendar has the dates. If you are not, keep going.
File even if you cannot pay
Sending the return stops the filing penalties from climbing. It does not magically clear the tax, but it turns two problems into one. If the money is the issue, file first, then follow what to do if you cannot afford the bill.
Late filing
HMRC charges you for a late return like this:
- The day after the deadline: £100. This is charged even if you have no tax to pay.
- After 3 months: £10 a day, capped at £900 (90 days).
- After 6 months: a further 5% of the tax due, or £300, whichever is greater.
- After 12 months: another 5% or £300, whichever is greater.
A return that is a year late with tax outstanding can cost £100 + £900 + two percentage charges. The £100 is automatic. The later charges need tax to be due before they bite at the 5% level, but the £300 minimum still applies.
If you are in a partnership, each partner can be charged.
Late payment
This is a different ladder, on the unpaid tax:
- 30 days late: 5% of the tax still unpaid
- 6 months: another 5%
- 12 months: another 5%
Interest also runs from the day after the deadline until the tax is paid. Paying a chunk now, even if you cannot clear it, reduces the figure those percentages apply to.
HMRC has a penalty estimator if you want a number.
They stack
A late return with late tax means both ladders. File a year late and still owe the bill, and you are looking at filing penalties plus three 5% late-payment charges plus interest. That is why "I'll deal with it when I have the money" is the expensive order. File now. Arrange the tax second.
Late registration is a third thing
If you never registered in the first place, you may also have a failure-to-notify penalty. That is a percentage of the tax you should have paid, and it is separate from the two ladders above. Registering late covers that one. The practical order is still: register, get the UTR, file, pay or arrange to pay.
One useful exception on filing: if you register after 5 October, HMRC should send a letter or email giving you three months from that notice to send the return. The 31 January payment date does not move. You can be on time with the form and still late with the money.
Reasonable excuse
If something outside your control stopped you filing or paying, and you sorted it as soon as that thing passed, you can appeal the penalty. Serious illness, a close bereavement, a fire or flood, or HMRC's own systems being down can count.
Not knowing the deadline, finding the form confusing, or waiting on an accountant who went quiet generally does not. "I could not afford it" is not a reasonable excuse for a late return. It can be a reason to set up a payment plan for the tax.
You usually have 30 days from the date on the penalty notice to appeal. The notice itself tells you how.
What to do this afternoon
- If you have no UTR, register now and wait for the letter. You cannot file without it.
- If you have a UTR, file the return online. Use the best figures you have. Provisional figures are allowed if you say so on the return and replace them later.
- Pay what you can today. Faster Payments from your bank is the quickest.
- If you cannot clear it, set up a Time to Pay plan rather than hoping HMRC forgets.
The first-timer walkthrough is the version of this process without the penalties piled on. Use it for next year.