Welsh land transaction tax: when WRA can assess a return for careless errors
When can WRA make an assessment?
WRA guidance says it can do so only in specified cases. Carelessness, deliberate action, later-discovered inaccuracies and what WRA knew can all matter.
- Check who gave the information
- Keep evidence of the care taken
- Act if you find an error later
Scroll down for the full analysis.
Read the original guidance here:
Welsh land transaction tax: when WRA can assess a return for careless errors
Welsh land transaction tax: when WRA can assess a return for careless errors
The Welsh Revenue Authority, or WRA, cannot simply reopen a tax return whenever it wants, because its technical guidance allows an assessment only in set situations. The limits matter. Key questions often include whether an error was careless or deliberate, what WRA knew at the time, and whether the return followed accepted practice.
What this rule is about
An assessment is a formal step WRA may take after looking at a tax return. It can matter when WRA thinks a return contains a problem described in its related TCMA/1100 guidance.
This goes beyond a typing error. The guidance looks at how the problem happened and what became known later. That can make a real difference.
The supplied page does not list the TCMA/1100 situations. This page therefore explains the conditions for an assessment, not every type of problem that may lead to one.
What the official source says
The WRA technical page says it may make an assessment only in the circumstances it lists, including where you, someone acting for you, or a partner in the same partnership caused the relevant situation carelessly or deliberately. That is one route.
- Carelessness means failing to take reasonable care to avoid the situation.
- It can also include finding out later that information was inaccurate.
- In that case, the guidance says you must take reasonable steps to tell WRA.
- A deliberate action can also lead to an assessment.
- This includes deliberately inaccurate information in a document sent to WRA.
There are other routes: after WRA’s chance to open an enquiry has ended, or after it has finished one, it may act if it could not reasonably have been expected to know about the relevant situation from the information then available. Timing matters.
The source also says WRA may make an assessment when it makes an adjustment under the general anti-avoidance rule.
What this means in practice
You may think using an agent ends your responsibility for a return. It does not. The guidance includes information supplied by someone acting on your behalf.
What matters in practice? Keep a clear record of what you checked, what you were told, and what you did when you spotted a possible error.
- Check the return before it is sent to WRA.
- Keep emails, figures and documents used to prepare it.
- Record any later discovery that information was wrong.
- Keep proof of steps taken to tell WRA about it.
The guidance limits WRA’s power where a mistake about the basis for working out tax caused the relevant situation and the return followed practice generally prevailing when it was made. Both parts matter.
A mistake alone is not enough.
How to analyse it
Start with the exact issue WRA says exists. Then work through the facts in order. Do not jump straight to whether the result feels fair.
- Identify the relevant situation described in TCMA/1100.
- Ask whether it resulted from an error in the return.
- Work out who supplied the information and who made the decision.
- Consider what reasonable care looked like in those circumstances.
- If an error was found later, check what was done and when.
Next, consider what WRA knew: if it had already finished an enquiry, the source says the information available to it at that time matters because the question is whether WRA could reasonably have been expected to spot the issue from it. Look closely.
Finally, test the accepted-practice protection. Was the issue a mistake about the basis used to work out tax? Was that basis generally followed when the return was made?
Example
Sam sends a return using figures prepared by an agent, then months later finds an email showing that one figure given to the agent was wrong. Sam does nothing.
Under the WRA guidance, that later discovery and failure to take reasonable steps to tell WRA may mean the situation is treated as careless.
Change one fact. Sam spots the error and promptly tells WRA, keeping a copy of the message. That does not decide every issue, but it removes the particular failure to notify described in the source.
Why this can be difficult in practice
Evidence is usually the hard part. The supplied page does not give “reasonable care” a fixed checklist.
What was sensible may depend on the return, the information available, and the role of any agent or partner. Context matters.
Accepted practice can also be hard to prove, because it means more than saying that one person gave you that view and requires evidence that the practice was generally followed at the relevant time. You need evidence.
- An agent’s mistake does not automatically settle the question.
- Finding an error later can create a separate duty to act.
- A completed enquiry does not always prevent an assessment.
Key takeaways
- WRA guidance says an assessment is available only in listed circumstances.
- Carelessness can include failing to report information later found to be wrong.
- Accepted practice may matter, but the source sets two conditions for that protection.
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.
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 supplied materials do not include the underlying Tax Collection and Management (Wales) Act 2016 provisions or a currency notice for them.
- The facts that count as reasonable care, reasonable steps, a deliberate action, and generally prevailing practice can depend on the individual case.
- The source does not set out the TCMA/1100 situations that can lead to an assessment.
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 return and all information sent to WRA
- Records showing the checks made before the return was filed
- Dates when any error was found and when WRA was told
- Evidence of the tax practice generally followed when the return was made
- Details of anyone who prepared or supplied information for the return
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 When the WRA Can Make a Tax Assessment [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.] Guidance page from the Welsh Revenue Authority on this topic (guidance, not law): https://www.gov.wales/tax-collection-and-management-wales-act-2016-tax-returns-enquiries-and-assessments-technical#5942 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 supplied materials do not include the underlying Tax Collection and Management (Wales) Act 2016 provisions or a currency notice for them. - The facts that count as reasonable care, reasonable steps, a deliberate action, and generally prevailing practice can depend on the individual case. - The source does not set out the TCMA/1100 situations that can lead to an assessment. 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: Welsh land transaction tax: when WRA can assess a return for careless errors
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