LTT late payment interest: what happens if Wales stamp duty is late
LTT late payment interest
The Welsh Revenue Authority charges simple interest where Land Transaction Tax or a penalty remains unpaid. For most LTT amounts, interest starts the day after the filing date.
- The rate is the Bank of England rate plus 2.5 percentage points.
- Later corrections do not usually change the original interest start date.
- Different timing rules apply where no return was made.
Scroll down for the full analysis.
Read the original guidance here:
LTT late payment interest: what happens if Wales stamp duty is late
LTT late payment interest: what happens if Wales stamp duty is late
Pay Land Transaction Tax late and the Welsh Revenue Authority can charge interest on the unpaid amount.
It normally starts the day after the filing date. The longer the tax stays unpaid, the more interest builds up.
What this rule is about
Late payment interest charges you for paying tax after it should have been paid. It is separate from any penalty.
You can therefore face interest even where there is no penalty.
The key point is that interest can start from the original filing date even when an amended return or WRA notice reveals the amount later.
That date can matter most.
What the official source says
The WRA’s technical guidance says it charges interest on unpaid tax from the relevant late-payment interest start date until payment is made, including non-business days.
There is no weekend break.
- For an amount in your tax return, interest starts the day after the filing date.
- The same start date applies if you amend your return.
- It also applies where the WRA corrects your return.
- An amendment made by the WRA under sections 45 or 50 has the same starting point.
- For a WRA assessment, interest normally starts the day after the filing date.
- If the WRA makes a determination because no return was made, it starts after the date when the return should have been filed.
- The same rule applies to an assessment where no return was made.
The guidance calls this simple interest. It charges interest on unpaid tax, not on interest already built up.
The annual rate is the Bank of England rate plus 2.5 percentage points. That is a formula, not a fixed rate.
The Bank of England rate may change.
What this means in practice
Paying tax late can cost more than the missing amount. A later correction does not usually move the interest start date forward.
That catches people out.
- Check the filing date, not just the date you found the error.
- Keep proof of the day the WRA received payment.
- Include amounts set off against money the WRA owes you.
- Ask for a receipt if you want one. The guidance says the WRA must provide it when requested.
- Do not assume a weekend or bank holiday delays the interest start date.
Interest on an unpaid penalty differs in one respect: it starts when the penalty was due to be paid, rather than by reference to a return filing date.
Its clock uses another date.
How to analyse it
Start with the amount still unpaid. Then identify why that amount is due.
That answer sets the clock.
- Was the amount shown in an original return?
- Did you amend the return, or did the WRA issue a correction?
- Did the WRA amend, determine or assess the amount?
- Was a return missing when the WRA acted?
- What was the relevant filing date, or the date the return should have been filed?
- When was the tax paid, or set off?
- Is the unpaid amount tax, a penalty, or both?
For a penalty, check its payment due date. The WRA says interest runs from that date until you pay it in full.
Example
Rhodri files an LTT return but leaves £10,000 unpaid after the filing date. Interest starts the next day.
It runs until the WRA receives the £10,000.
If the Bank of England rate at the relevant time is used with the published formula, the annual rate is that Bank rate plus 2.5 percentage points.
No interest is added to earlier interest.
Now change one fact. If Rhodri made no return and the WRA later made an assessment, interest starts the day after his return should have been filed.
That becomes the relevant starting point.
Why this can be difficult in practice
Most disputes are likely to concern dates and amounts, rather than the basic formula. A correction letter may arrive much later than the filing date.
That delay may not help.
On the WRA’s account of the rule, it does not automatically stop interest running from the earlier date.
- A payment may cover only part of the tax due.
- A later amendment can reveal tax that was missing from the first return.
- A set-off may count as payment even where no money changes hands.
- Estate cases need careful records of the grant date and whether payment was possible before then.
- The current Bank of England rate and applicable interest rate should be checked for the period in question.
There is a special estate rule. Where someone dies before an amount becomes due and payable, and their executor cannot pay before probate or letters of administration, the start date is the later of the normal date and 30 days after the grant.
Records matter here.
Key takeaways
- Late LTT can attract interest from the day after the filing date.
- Interest is simple and uses the Bank of England rate plus 2.5 percentage points.
- Unpaid penalties can also attract interest from their payment due date.
Technical analysis
For advisers, and for anyone who wants to check the law behind this page. You do not need this section to understand the guidance above.
Legislation
- TCMA 2016 section 41 — taxpayer amendments to tax returns
- TCMA 2016 section 42 — WRA corrections of tax returns
- TCMA 2016 section 45 — WRA amendments to tax returns
- TCMA 2016 section 50 — WRA amendments to tax returns
- TCMA 2016 section 52 — WRA determinations where returns are missing
- TCMA 2016 section 54 — WRA assessments of unpaid tax
- TCMA 2016 section 55 — WRA assessments of unpaid tax
Official guidance
The pages below are the Welsh Revenue Authority’s guidance. Guidance is not law. It sets out how the Welsh Revenue Authority reads the legislation, and it is not binding on you, on a tribunal or on a court. Where guidance and the legislation differ, the legislation wins. the Welsh Revenue Authority can also change or withdraw guidance, and it may not cover your facts.
Where this is not settled
- The applicable Bank of England rate can change. The source gives the formula, not a fixed current percentage.
- The supplied statutory material does not include the late-payment interest provisions or the 2018 Regulations themselves.
Evidence you would need
This kind of case is decided on the facts of the individual property. These are the records that usually settle it, and the ones an adviser would ask you for.
- The original tax return and its filing date
- Any amended return, correction notice, determination or assessment
- Proof of when each amount was paid or set off
- For an estate, the grant of probate or letters of administration
Explore this with an AI
Readers often want to test their own situation. Copy the prompt below into ChatGPT, Claude or Gemini. It hands the model the actual legislation for this page rather than letting it answer from memory, and tells it to be explicit about what is uncertain. What comes back is information, not advice – check it against the links above.
I am researching Land Transaction Tax (LTT), the tax on property in Wales. It replaced Stamp Duty Land Tax in Wales on 1 April 2018, and SDLT does not apply in Wales. MY QUESTION LTT late payment interest: what happens if Wales stamp duty is late [Replace this with your own situation: what you are buying, the price, the dates, who the buyer is, and what you plan to do with the property.] THE LAW THIS TURNS ON - TCMA 2016 section 41 - taxpayer amendments to tax returns https://www.legislation.gov.uk/anaw/2016/6/section/41 - TCMA 2016 section 42 - WRA corrections of tax returns https://www.legislation.gov.uk/anaw/2016/6/section/42 - TCMA 2016 section 45 - WRA amendments to tax returns https://www.legislation.gov.uk/anaw/2016/6/section/45 - TCMA 2016 section 50 - WRA amendments to tax returns https://www.legislation.gov.uk/anaw/2016/6/section/50 - TCMA 2016 section 52 - WRA determinations where returns are missing https://www.legislation.gov.uk/anaw/2016/6/section/52 - TCMA 2016 section 54 - WRA assessments of unpaid tax https://www.legislation.gov.uk/anaw/2016/6/section/54 - TCMA 2016 section 55 - WRA assessments of unpaid tax https://www.legislation.gov.uk/anaw/2016/6/section/55 Guidance page from the Welsh Revenue Authority on this topic (guidance, not law): https://www.gov.wales/tax-collection-and-management-wales-act-2016-interest-technical-guidance#6673 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. Guidance from the Welsh Revenue Authority is its view of the law, not the law, and does not bind a tribunal or a court. 2. Tell me what the rule actually requires, in plain English. 3. Tell me which facts decide the answer, and which facts would change it. 4. Tell me what evidence I would need to support the position. 5. Be explicit about anything unsettled or fact-sensitive. Do not guess. 6. Your training data has a cutoff and SDLT rates and reliefs change at fiscal events. Say so if you are not sure the law is current. POINTS ALREADY KNOWN TO BE UNCERTAIN ON THIS TOPIC - The applicable Bank of England rate can change. The source gives the formula, not a fixed current percentage. - The supplied statutory material does not include the late-payment interest provisions or the 2018 Regulations themselves. Do not give me a conclusion you cannot support from the provisions above.
Legislation links show the Land Transaction Tax and Anti-avoidance of Devolved Taxes (Wales) Act 2017 as it stood on 2025-11-17. The law may have changed since, and the rules that apply are those in force on the date of your transaction. The official guidance this page is based on is here.
This page was last updated on 3 September 2026
Useful article? You may find it helpful to read the original guidance here: LTT late payment interest: what happens if Wales stamp duty is late
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