When common stamp duty practice can block an overpayment claim
In brief
HMRC says a stamp duty overpayment claim can be blocked if the error followed a practice generally accepted when the tax was calculated.
- The practice must be established, visible and accepted.
- HMRC says it must prove the practice if the issue is disputed.
- The manual’s PAYE reference does not match the SDLT legislation.
Scroll down for the full analysis.
Read the original guidance here:
When common stamp duty practice can block an overpayment claim
When common stamp duty practice can block an overpayment claim
You may have paid too much stamp duty, but that does not always mean HMRC must repay it. A special limit, known as Case G, can apply where the mistake followed a tax practice that was widely accepted at the time.
What this rule is about
Overpayment relief is a way to ask HMRC to repay stamp duty land tax that was not due. It can cover HMRC demands you dispute.
Your calculation may now appear wrong, yet if it followed the usual approach when you filed the return, and that approach was widely accepted at the time, Case G may matter. Timing matters.
That distinction matters. A later change in how a rule is understood does not always reopen an old tax calculation.
What the official source says
HMRC’s manual says that overpayment relief is not available where too much tax arose from a mistake in calculating tax, and the calculation followed the practice generally prevailing at that time.
In everyday terms, HMRC is asking whether there was a recognised and established way of dealing with the point when the calculation was made. It is not enough that one person, firm or website took that view.
- HMRC says the question is one of fact, based on what really happened at the time.
- The practice should have been in place for a reasonable period.
- People affected by it should have been able to find out what it was.
- HMRC and tax advisers should both have accepted it.
- Not every person needs to have followed the practice.
- If the point reaches an appeal, HMRC’s manual says HMRC must show that the practice existed.
HMRC takes that view even if people are still challenging the decision.
What this means in practice
The key question is not simply whether the return was wrong. You must also ask both why it was wrong and which approach people generally used at the time.
If there was no settled common approach, Case G may not apply. Equally, a clear mistake in the return is not automatically protected just because someone says it was common.
- Keep the return, calculations and supporting papers.
- Save HMRC guidance that was available when you filed.
- Keep any written advice that explains the approach used.
- Look for professional material published at the same time.
- Check whether the approach had already been found to be wrong.
People often overlook this: current HMRC guidance may not reveal the practice of years ago. The relevant time is when someone calculated the tax.
How to analyse it
Start with the basic issue. Was stamp duty overpaid because the calculation used the wrong legal approach? If so, work through the evidence in order.
- Identify the exact part of the calculation said to be wrong.
- Fix the date when the return and calculation were made.
- Find the guidance, advice and published material available then.
- Ask whether they show a clear and established shared approach.
- Check whether HMRC appeared to accept that approach.
- Check whether advisers generally accepted it too.
- Find out whether a decision had already rejected the approach.
- Consider the other limits on overpayment relief, not only Case G.
Do not treat an HMRC manual as the final answer. The legislation is the law. The manual is useful evidence of HMRC’s view, but it does not bind you.
Example
Imagine Priya filed an SDLT return using an approach set out in HMRC material and echoed in professional guides. Years later, it becomes clear that the approach was wrong and Priya paid too much tax.
Her claim may face Case G if the approach was genuinely common when she filed. HMRC would need to support that position with evidence. If only one old article mentioned the approach, or someone had already disputed it, the outcome may differ.
Why this can be difficult in practice
“Generally prevailing” sounds simple, but it is not a headcount. The real issue is whether there was a settled, visible and accepted practice at the relevant time.
Old guidance can disappear or change. Advisers may have given advice orally. Different advisers may also have taken different views. Those facts can decide the result.
- Following HMRC guidance may be important evidence, but it may not settle the legal question.
- A widespread practice can still be wrong in law.
- A practice does not have to be universal to count.
- A practice can end before HMRC changes every page of guidance.
- The manual’s reference to PAYE income does not match the SDLT wording in the legislation.
The statute contains a different exception where tax was charged contrary to EU law. Because of that mismatch, the PAYE point in the manual should not be treated as an SDLT rule without checking the current primary law.
Key takeaways
- Paying too much stamp duty does not always guarantee a repayment.
- Case G can block a claim based on a once-common calculation approach.
- What mattered at the time of the return is central.
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
- FA 2003 Schedule 10 para 34 — claims to recover stamp duty not due
- FA 2003 Schedule 10 para 34A — exclusions from overpayment relief claims; Case G and generally prevailing practice; exception for tax charged contrary to EU law
Official guidance
The pages below are HMRC’s guidance. Guidance is not law. It sets out how HMRC 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. HMRC can also change or withdraw guidance, and it may not cover your facts.
Where this is not settled
- It is unclear why this SDLT manual page refers to a PAYE-income exception when the SDLT legislation instead refers to tax charged contrary to EU law.
- Whether a practice was long-established, clear and accepted by both HMRC and advisers depends on the evidence available at the relevant time.
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 SDLT return and calculation
- the date the return was made
- HMRC guidance available at that date
- professional publications or advice showing the wider practice
- material showing when any decision found the practice wrong
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 UK Stamp Duty Land Tax (SDLT), which applies in England and Northern Ireland. MY QUESTION When common stamp duty practice can block an overpayment claim [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 - FA 2003 Schedule 10 para 34 - claims to recover stamp duty not due https://www.legislation.gov.uk/ukpga/2003/14/schedule/10/paragraph/34/2025-11-17 - FA 2003 Schedule 10 para 34A - exclusions from overpayment relief claims https://www.legislation.gov.uk/ukpga/2003/14/schedule/10/paragraph/34A/2025-11-17 - FA 2003 Schedule 10 para 34A - Case G and generally prevailing practice https://www.legislation.gov.uk/ukpga/2003/14/schedule/10/paragraph/34A/2025-11-17 - FA 2003 Schedule 10 para 34A - exception for tax charged contrary to EU law https://www.legislation.gov.uk/ukpga/2003/14/schedule/10/paragraph/34A/2025-11-17 HMRC's guidance page on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm54170 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. HMRC guidance is HMRC's 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 - It is unclear why this SDLT manual page refers to a PAYE-income exception when the SDLT legislation instead refers to tax charged contrary to EU law. - Whether a practice was long-established, clear and accepted by both HMRC and advisers depends on the evidence available at the relevant time. Do not give me a conclusion you cannot support from the provisions above.
Legislation links show Finance Act 2003 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 1 September 2026
Useful article? You may find it helpful to read the original guidance here: When common stamp duty practice can block an overpayment claim
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