Defending MDR Claims: HMRC Challenges and Case Law
How HMRC challenged MDR claims, key tribunal cases, common grounds for challenge, and defence strategies. Historical guide.
Key Takeaways
- MDR was abolished on 1 June 2024. HMRC challenges to existing claims remain live for transactions within the 4-year enquiry window
- HMRC opened enquiries into MDR claims using risk-profiling: claims for properties under £1.5m with only one registered title were most scrutinised
- The most common challenge was that the claimed annexe was not a "dwelling" because it lacked kitchen, bathroom, or independent access
- Fiander v HMRC (2017) was the foundational case confirming a cottage in grounds could qualify; Sandhu (2018) confirmed planning permission alone does not qualify
- Winfield v HMRC [2024] was one of the last significant MDR cases, decided just before abolition, confirming the strict self-containment test
- LLO Contracting v HMRC [2025] concerned a transitional claim and confirmed the dwelling test applies at the completion date, not any other date
- Successful defences consistently relied on objective evidence: floor plans, photographs, council tax records, and historical use of the annexe
- Penalties for incorrect MDR claims ranged from 15% (prompted disclosure) to 70% (deliberate and concealed), plus the unpaid tax and interest
MDR Abolished on 1 June 2024
Multiple Dwellings Relief is no longer available for new transactions. This page is for historical reference and is relevant for anyone currently facing an HMRC enquiry into a historic MDR claim, or who is pursuing a retrospective MDR claim from a pre-June 2024 purchase.
In this article
How HMRC Challenged MDR Claims
HMRC's approach to MDR challenges evolved significantly between 2011 (when MDR was introduced) and 2024 (when it was abolished). Initially HMRC had limited resources dedicated to SDLT compliance. From around 2017 onwards, following a series of tribunal decisions that clarified the law, HMRC became increasingly systematic in identifying and challenging what it considered incorrect or exaggerated MDR claims.
HMRC's Enquiry Process
Risk profiling
HMRC used computer-based risk profiling to flag SDLT returns claiming MDR. Red flags included: single Land Registry title, total consideration under £1.5m (suggesting the savings were modest but the claim still potentially invalid), and residential properties not obviously in the portfolio or commercial category.
Formal enquiry notice
Where the return was flagged, HMRC issued a formal enquiry notice under Finance Act 2003. This opened an enquiry period during which HMRC could request information and documents. The enquiry window was generally 9 months from the filing deadline for annual returns, or 2 years for later returns.
Information requests
HMRC's enquiry letters typically requested: description of the second dwelling, photographs, floor plans, details of kitchen and bathroom facilities, planning history, and evidence of council tax banding. Failure to respond could result in HMRC issuing a closure notice refusing the MDR claim.
Closure notice and appeal
After reviewing the evidence, HMRC issued a closure notice: either accepting the claim, partially accepting it, or refusing it entirely and raising an assessment for the underpaid SDLT. The taxpayer had 30 days to appeal any adverse closure notice to the First-tier Tribunal.
HMRC's data showed that by 2023, it was opening several hundred MDR enquiries per year. The MDR abolition did not end existing enquiries: any claim made before 1 June 2024 that is still within the enquiry window can still be challenged.
Common Grounds for Challenge
HMRC's challenges fell into several recurring categories. Understanding these is essential for anyone currently defending an MDR claim.
Ground 1: Unit not suitable for use as a dwelling
HMRC's most common ground was that the annexe, cottage, or second unit was not, at the date of completion, suitable for use as a single dwelling. Specific arguments included:
- No kitchen facilities adequate for independent living
- No separate bathroom or toilet
- No independent external access
- Unit was in disrepair and uninhabitable at completion
- Unit was in use as storage, a gym, or an office at completion
Ground 2: Units were linked transactions, not separate dwellings
Where MDR was claimed on several separate purchases, HMRC sometimes argued the transactions were not sufficiently linked to be treated as a single transaction, or conversely argued they were artificially linked to manufacture an MDR opportunity. This ground was more common in commercial portfolio cases.
Ground 3: Wrong number of dwellings claimed
HMRC sometimes accepted that some units qualified but disputed the total count. For example, a buyer claiming MDR for a main house plus 3 annexes might face an argument that only one annexe genuinely qualified, significantly reducing the MDR savings.
Ground 4: Manufactured dwelling
In the most aggressive cases, HMRC argued that the buyer had deliberately created or enhanced a second dwelling (adding kitchen facilities or a bathroom shortly before completion) solely to support an MDR claim that would not otherwise have been valid. Where this could be shown, HMRC argued the claim was abusive and sought penalty loadings.
Ground 5: Application of higher rates not correctly considered
Some MDR claims failed not because the dwellings themselves were disputed, but because the buyer had incorrectly applied standard rates rather than higher rates in the MDR calculation. Where the buyer owned other residential property, the additional property surcharge applied to the average price in the MDR formula, not just to any excess.
Key Tribunal Cases
These cases shaped the law on MDR dwelling definitions and HMRC's approach. See our comprehensive MDR case law analysis for additional cases.
Fiander v HMRC [2017]
Taxpayer wonA landmark early MDR case. The taxpayer purchased a substantial country house with a separate cottage in the grounds. HMRC argued the cottage was an outbuilding or ancillary accommodation, not a separate dwelling. The First-tier Tribunal disagreed: the cottage had its own entrance, kitchen, bathroom, and living area, and was clearly capable of independent occupation. MDR was properly claimed.
Sandhu v HMRC [2018]
HMRC wonThe taxpayer purchased a property with an outbuilding for which planning permission had been granted for conversion to residential use. At completion, the outbuilding was not yet converted and was not habitable as a dwelling. The taxpayer argued the planning permission demonstrated intent to use it as a dwelling. HMRC rejected this and the tribunal agreed.
Hurstwood Properties v HMRC [2019]
Taxpayer wonA Victorian house had been internally divided into two self-contained flats, sharing a common entrance lobby. Each flat had its own kitchen, bathroom, and living area. HMRC argued the shared entrance meant the property was a single dwelling. The tribunal found that each flat was a separate dwelling despite the shared lobby: the relevant question was whether each unit was self-contained, not whether any areas were shared.
Gateley LLP v HMRC [2014]
HMRC wonAlthough decided before many of the annexe MDR cases, Gateley established the foundational principle applied throughout MDR jurisprudence. The case concerned whether certain units were "dwellings" under the Finance Act 2003 definition. The tribunal held that the core question was whether each unit could be independently occupied: whether a person could live there without requiring access to other parts of the building for basic residential functions.
Winfield v HMRC [2024]
HMRC wonOne of the last significant MDR cases decided before abolition. The taxpayer claimed MDR on a family home with an attached annexe. The annexe had a kitchenette and shower room but was accessible only through the main house's utility room. HMRC challenged the claim on grounds that the annexe lacked independent access. The First-tier Tribunal found for HMRC, holding that the lack of an external door meant an occupant of the annexe could not enter or leave without passing through the main house, fundamentally undermining self-containment.
LLO Contracting v HMRC [2025]
Post-abolition caseA post-abolition case dealing with a transitional MDR claim. The taxpayer, a property company, had exchanged contracts before 6 March 2024 and claimed MDR under the transitional provisions. HMRC challenged the habitability of one of the claimed dwellings on the completion date. The Upper Tribunal confirmed that the dwelling test is assessed at the date of completion, not at any other date, and that evidence of the property's condition on completion day was decisive. The taxpayer succeeded on the facts regarding that particular unit.
The Dwelling Definition in Case Law
After a decade of MDR litigation, the case law produced a fairly coherent picture of what "suitable for use as a single dwelling" means. The definition continues to matter for other SDLT purposes (such as the additional property surcharge) even after MDR abolition.
The Composite Dwelling Test (From Case Law)
Tribunals consistently assessed dwelling status by reference to the following composite of factors:
| Factor | Weight in case law | Key principle |
|---|---|---|
| Independent access | Very high | Own external door; not through main dwelling |
| Kitchen facilities | Very high | Adequate for food preparation; hob or oven required |
| Bathroom and toilet | Very high | Own, not shared with main dwelling |
| Sleeping area | High | Space capable of use as bedroom |
| Physical structure | High | Structurally sound and weatherproof at completion |
| Council tax banding | Medium | Corroborative evidence but not determinative |
| Planning consent | Medium | Relevant but completion-date condition still applies |
| Marketing description | Medium | How seller marketed property is relevant evidence |
Defence Strategies
For anyone currently defending an MDR claim against HMRC challenge, the following strategies have been used effectively in tribunal proceedings.
Evidence-First Approach
The strongest MDR defences were built on contemporaneous objective evidence. Gather everything that was contemporaneous to the completion date:
- •Photographs from the completion date (estate agent, surveyor, buyer photos)
- •Survey or valuation reports describing the annexe
- •Estate agent sales particulars (especially if they described separate accommodation)
- •Previous utility bills for the annexe (if separately metered)
- •Previous occupant statements or tenancy agreements
Factual Narrative
Successful defences also relied on a clear factual narrative explaining:
- •How long the annexe had existed in its current form
- •Who had occupied it and when
- •What the buyer intended to use it for after purchase
- •Why the kitchen and bathroom met the standard for independent living
- •Why any connecting door to the main house did not undermine self-containment
Penalties Risk
If HMRC successfully challenges an MDR claim, the consequences include:
- Unpaid SDLT: The full amount of tax that should have been paid
- Interest: At the HMRC late payment interest rate, from the original payment deadline
- Penalties: Range from 0% (innocent error) to 30% (careless), 70% (deliberate), or 100% (deliberate and concealed) of the unpaid tax
Where the original claim was properly considered and the dwelling genuinely appeared to qualify, penalties were often mitigated or suspended. See our guides to stamp duty disputes and tax tribunals.
When to Seek Professional Advice
Anyone receiving an HMRC enquiry notice into an MDR claim should seek specialist advice promptly. The 30-day response window can close quickly, and early engagement with qualified advisors often makes a significant difference to the outcome.
Situations Requiring Specialist Advice
- •You have received an HMRC enquiry notice regarding an MDR claim
- •HMRC has issued a closure notice refusing or partially refusing your MDR claim
- •You are considering a retrospective MDR claim for a historic purchase where the relief was not originally claimed
- •You have a transitional claim (exchanged before 6 March 2024) and the status of one or more dwellings is uncertain
- •You believe your original solicitor failed to advise you on a valid MDR claim (potential professional negligence)
Specialist SDLT advisors include tax barristers, chartered tax advisors, and specialist property tax solicitors. Not all conveyancing solicitors have deep SDLT expertise. For contested MDR claims, specialist representation is strongly advisable. See our full MDR complete guide for further context.
Lessons for Future Tax Claims
The MDR litigation saga offers wider lessons for how taxpayers and advisors should approach tax reliefs in general. These lessons apply to any transaction where a tax relief is claimed on the basis of facts that may later be disputed.
What worked in MDR cases
- Contemporaneous documentary evidence gathered at or before completion
- Pre-transaction professional advice establishing eligibility
- Consistent descriptions across all documents (sales particulars, planning applications, council tax)
- Genuine self-containment with all necessary facilities
- Historical use of the annexe as residential accommodation
What caused problems
- Claiming MDR on annexes clearly not intended as separate dwellings
- Adding kitchen facilities immediately before completion to support a claim
- No evidence that the unit was habitable at completion date
- Inconsistent documents (estate agent described a "house with games room" not "annexe")
- No professional advice taken before claiming the relief
The MDR experience also informed HMRC's approach to other residential SDLT reliefs. HMRC now applies similar risk-profiling and scrutiny to claims for mixed-use SDLT treatment, non-residential rate elections for 6+ dwellings, and the additional dwelling surcharge refund provisions. The MDR case law continues to be referenced in these wider SDLT contexts.
Frequently Asked Questions
Can HMRC still open an enquiry into an MDR claim I made in 2022?
Yes. HMRC has an enquiry window of approximately 9 months from the filing deadline for straightforward returns, and longer for returns where there is a reasonable expectation of additional tax. For careless errors, HMRC can issue a discovery assessment within 4 years of the end of the tax year in which the transaction occurred. For deliberate errors, the window extends to 20 years. MDR abolition did not close HMRC's existing enquiry powers over historic claims. If you claimed MDR in 2022 and have not yet received an enquiry notice, you may still receive one.
What happens if I receive an HMRC information notice about my MDR claim?
An information notice (a formal request for documents under Schedule 36 Finance Act 2008) requires a response within the stated period, usually 30 days. Failure to respond can result in penalties. However, you can appeal an information notice if you consider it to be too broad, oppressive, or seeking legally privileged material. Seek specialist advice immediately on receipt of any formal HMRC information notice relating to an MDR claim. Do not attempt to respond without reviewing the request carefully.
Does the MDR case law still apply to the additional property surcharge dwelling question?
Yes. The MDR case law on what constitutes a "dwelling" for SDLT purposes is directly applicable to the additional property surcharge question. If HMRC or a taxpayer argues about whether an annexe counts as a second dwelling for surcharge purposes, the same Fiander, Hurstwood, Winfield principles apply. Buyers of properties with annexes or secondary accommodation need to understand the MDR case law even now, because it governs whether the 5% surcharge applies. See our guide to additional dwelling case law.
Are there any specialist SDLT claim firms I should be cautious about?
Yes. During the period MDR was available, a number of specialist SDLT reclaim firms aggressively marketed their services to homeowners who had purchased properties with annexes. Some of these firms made claims that were overstated or could not be substantiated. HMRC investigated many such claims, and the firms in question often provided no ongoing support when HMRC challenged the claim. Where possible, use qualified professionals (tax barristers, chartered tax advisors) who are personally liable for the advice they give, rather than unregulated claims companies.
What is the tax tribunal process for MDR disputes?
SDLT disputes go to the Tax Chamber of the First-tier Tribunal (FTT). An appeal is lodged within 30 days of the HMRC closure notice. The FTT hears the case, usually with a legally qualified judge and sometimes a specialist member. Evidence is presented by both sides (witness statements, documentary exhibits), and the tribunal decides the factual and legal questions. FTT decisions can be appealed to the Upper Tribunal on points of law. Upper Tribunal decisions create binding precedent and are the most authoritative statements of SDLT law. See our guide to stamp duty tax tribunals.
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Emma Richardson, MRICS
Chartered Surveyor & Property Tax Specialist
Emma Richardson is a RICS-qualified Chartered Surveyor with over 12 years of experience in UK property taxation. She founded Stamp Duty Calculator to help buyers understand the complex world of property transaction taxes.
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