Stamp Duty Legal Hub
HMRC compliance, case law, anti-avoidance rules, and tax tribunal procedures for SDLT. Getting the legal side right protects you from penalties. Getting it wrong can cost far more than the original tax bill.
HMRC & Compliance
Legal Precedents & Cases
Your SDLT Obligations: Timeline
From completion to the HMRC enquiry window, understanding the key dates in the SDLT lifecycle helps you stay compliant and avoid costly mistakes.
Effective date (completion)
SDLT return clock starts. Instruct your solicitor to prepare the SDLT1 form.
SDLT filing deadline
SDLT return must be filed AND tax paid by this date. Late filing triggers automatic £100 penalty.
Late filing penalties begin
£100 automatic penalty. Interest accrues on unpaid tax at HMRC's standard rate (7.75% p.a. from 9 January 2026).
Penalty escalates
Late filing penalty rises to £200. This replaces the £100 rather than adding to it. Late payment of the tax carries interest, not a separate SDLT penalty.
HMRC enquiry window
HMRC can open a compliance check within 9 months of the filing deadline for routine cases.
Amendment window closes
Buyers can amend an SDLT return within 12 months of the filing deadline. After that, overpaid tax can only be reclaimed through an overpayment relief claim within 4 years, and underpaid tax should be disclosed to HMRC.
Penalty Summary
Late filing and incorrect returns attract fixed and tax-geared penalties. These are separate from the interest charged on any unpaid tax.
| Trigger | Penalty | Interest Charged? |
|---|---|---|
| Filed 1 day late | £100 flat | Yes |
| Filed 3+ months late | £200 flat | Yes |
| Filed 12+ months late | Up to 100% of tax due, on top of £200 | Yes |
| Tax paid late | No separate SDLT penalty | Yes |
| Inaccurate return (careless / deliberate / deliberate and concealed) | Up to 30% / 70% / 100% of the extra tax | Yes |
| Offshore non-disclosure | Up to 200% of tax due | Yes |
Buying through a company? The rates are different
Companies pay the 5% surcharge on homes, and a flat 17% above £500,000 unless a relief applies.
High-Risk Areas Under HMRC Scrutiny
HMRC targets specific categories of SDLT return where it believes non-compliance is widespread. If your purchase falls into one of these areas, ensure it is well documented.
Mixed-use classification
Claiming mixed-use rates on a home by pointing to a paddock, woodland or other minor non-residential element. HMRC has challenged many of these claims at tribunal, including Hyman v HMRC in the Court of Appeal in 2022, which the buyers lost.
Multiple dwellings annex claims
Past MDR or annexe claims that did not meet HMRC's tests. MDR was abolished for transactions from 1 June 2024, apart from contracts exchanged on or before 6 March 2024, but HMRC can still challenge earlier claims through enquiries and discovery assessments.
Additional dwelling surcharge avoidance
Using trust structures or nominee arrangements to avoid the 5% surcharge. Bare trusts and nominees are looked through to the beneficiary, and s75A can counteract multi-step schemes.
Linked transaction under-reporting
Splitting purchases to keep each below a rate threshold. Transactions between the same buyer and seller, or people connected with them, are linked under s108 FA 2003 when they form part of a single scheme, arrangement or series.
April 2025 Changed Everything
The nil-rate band dropped from £250,000 to £125,000 on 1 April 2025 and first-time buyer thresholds were significantly reduced. The additional dwelling surcharge had already risen from 3% to 5% on 31 October 2024 (Autumn Budget 2024). Every legal topic in this section includes before/after comparison tables showing how these changes affect compliance, disputes, and planning.