Stamp duty on a conditional property contract: substantial performance
Conditional contracts and stamp duty
A condition in a property contract does not prevent SDLT arising if the contract is substantially performed before completion.
- Taking possession can trigger the rule.
- Paying nearly all the price can also trigger it.
- The facts and timing need careful checking.
Scroll down for the full analysis.
Read the original guidance here:
Stamp duty on a conditional property contract: substantial performance
Stamp duty on a conditional property contract
A condition in your property contract does not always delay stamp duty when, before completion, you take possession or pay nearly all the price. SDLT may arise then. People call this substantial performance.
What this rule is about
Many property deals depend on something happening first, such as planning permission, before the parties can satisfy the condition and complete the sale formally.
That can mislead. You may think stamp duty only matters once that condition is met and the sale completes. That is not always right.
The key question is what has happened in practice. A conditional contract can still be substantially performed before formal completion.
What the official source says
HMRC’s manual says that a conditional contract remains within SDLT if it is substantially performed, even though the condition remains unmet and formal completion has not yet occurred.
That is guidance, rather than law. The legislation says that, when substantial performance happens before completion and the contract remains conditional, the contract is treated as the property transaction for SDLT purposes.
The timing matters.
- You take possession of all, or almost all, of the property.
- A person connected with you takes that possession.
- You pay or provide all, or almost all, of the amount due.
What this means in practice
The date of substantial performance becomes the effective date for SDLT. In simple terms, it can bring the tax point forward from completion.
- Do not assume an unmet condition ends the SDLT question.
- Check whether anyone has moved in or started receiving rent.
- Check payments made before the legal sale completes.
How to analyse it
Start with the real events, not just the contract label. The facts decide the answer.
- Read the condition and identify what remains to happen.
- Find the date possession was given.
- Check whether it covered all, or nearly all, of the property.
- Add up what was paid and compare it with the total due.
Example
Amir agrees to buy a shop for £200,000, subject to planning permission. Before permission is granted, he pays the full £200,000 and, under a temporary licence, can occupy the whole shop.
Although the condition remains unmet and completion has not happened, Amir has paid the full price and can occupy the whole shop. Those facts point strongly towards substantial performance. The relevant SDLT date may therefore be earlier than completion.
Why this can be difficult in practice
This is the part people get wrong. There is no set percentage for an amount that is “substantial”, and access to part of a property may not be enough.
- Keys alone may not show that full possession was given.
- A deposit is not automatically a substantial payment.
- A temporary licence can still count when considering possession.
Key takeaways
- A conditional contract can trigger SDLT before completion.
- Possession and payment are the main statutory tests.
- The detailed facts and dates matter.
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 section 44 — when contract performance triggers SDLT before completion
- FA 2003 section 119 — the effective date for a land transaction
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 can be unclear whether the buyer has taken the whole, or substantially the whole, of the property.
- It can also be unclear whether payments amount to substantially the whole of the price.
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 signed contract and every condition in it
- Completion and possession dates
- Any licence, lease or agreement allowing occupation
- Payment records and the total amount due
- Rent records, where the contract includes rent
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 Stamp duty on a conditional property contract: substantial performance [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 section 44 - when contract performance triggers SDLT before completion https://www.legislation.gov.uk/ukpga/2003/14/section/44/2025-11-17 - FA 2003 section 119 - the effective date for a land transaction https://www.legislation.gov.uk/ukpga/2003/14/section/119/2025-11-17 Guidance page from HMRC on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm08150 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. Guidance from HMRC 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 - It can be unclear whether the buyer has taken the whole, or substantially the whole, of the property. - It can also be unclear whether payments amount to substantially the whole of the price. 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 31 August 2026
Useful article? You may find it helpful to read the original guidance here: Stamp duty on a conditional property contract: substantial performance
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