Guidance on Powers of Attorney and SDLT Requirements for Land Transactions

When an Attorney Can Sign an SDLT Return

An attorney can sign an SDLT return for a purchaser only if the power of attorney is legally valid and clearly gives authority to deal with SDLT. HMRC will usually expect SDLT to be mentioned expressly, and general wording about the property purchase or mortgage may not be enough.

• The SDLT declaration is normally signed by the purchaser, but an attorney may sign if they have proper legal authority.
• HMRC says the power of attorney must be valid under the relevant law and must cover SDLT matters specifically.
• General authority to deal with the property, loan or mortgage will often not be accepted for SDLT purposes.
• Standard mortgage clauses called a “Power of Attorney” may fail if they do not meet legal requirements or do not mention SDLT.
• If the authority is defective, HMRC may reject the attorney’s signature and refuse to share confidential tax information with them.
• A court order may sometimes correct an invalid power and allow HMRC to accept the return and disclose information in line with that order.

Scroll down for the full analysis.

When an attorney can sign an SDLT return for a purchaser

This page explains when someone acting under a power of attorney can make the declaration in a Stamp Duty Land Tax (SDLT) return on behalf of a purchaser. The point matters because HMRC will not accept just any general authority to act. If the power of attorney is not legally valid, or does not clearly cover SDLT matters, HMRC may refuse to accept that the attorney can sign the return or receive confidential tax information.

What this rule is about

An SDLT return includes a declaration. Normally, that declaration must be made by the purchaser. In some cases, another person may act for the purchaser as their attorney. The question is when that is legally effective.

The source material deals with powers of attorney used for SDLT purposes. It focuses on whether the attorney has proper authority to deal with SDLT, not just general authority connected with the property transaction or mortgage.

The rule is also tied to taxpayer confidentiality. Even if a lender, broker or conveyancer is involved in the transaction, HMRC cannot disclose confidential SDLT information to them unless there is a proper legal basis for doing so.

What the official source says

HMRC says that where the SDLT declaration is made by an attorney under:

• a General Power of Attorney,
• an attorney appointed under section 10 of the Powers of Attorney (Northern Ireland) 1971, or
• in Scotland, an attorney appointed under the common law of agency,

the power of attorney must do two things:

• it must be legally valid, and
• it must give the attorney power to deal with SDLT matters.

HMRC says it will normally expect SDLT matters to be referred to expressly in the document. If they are not, HMRC may take the view that it is unclear whether the purchaser intended to give authority over SDLT and whether they gave informed consent to that authority.

If there is no valid power of attorney that includes SDLT powers, HMRC’s position is that only the purchaser can sign the declaration in the land transaction return.

The manual also highlights a recurring problem with mortgage documentation. Some mortgage terms contain a section called “Power of Attorney”, but HMRC says these clauses often do not satisfy the statutory requirements for a valid power of attorney and do not expressly cover SDLT matters. In those cases, HMRC does not accept that the lender or its agent is authorised to submit the SDLT return on the purchaser’s behalf.

HMRC also says it cannot disclose confidential taxpayer information to such a lender or agent unless there is a proper statutory basis. The source refers to section 18 of the Commissioners for Revenue and Customs Act 2005, which protects taxpayer confidentiality.

If a court order has been obtained that rectifies an invalid power of attorney and authorises disclosure of taxpayer information, HMRC says it can then disclose information in line with that order and accept a return filed under the rectified power.

What this means in practice

The practical message is simple: if someone other than the purchaser is going to sign the SDLT declaration, the authority for that must be properly documented and must clearly extend to SDLT.

A broad statement that someone can “deal with the property” or “act in connection with the mortgage” may not be enough. HMRC’s stated approach is that SDLT should normally be mentioned explicitly. That is because signing an SDLT return is not just an administrative step in the conveyancing process. It is a tax declaration made on the purchaser’s behalf.

This matters particularly where lenders or their agents try to rely on standard mortgage wording. HMRC is signalling that a clause tucked into mortgage terms may not create a valid power of attorney for SDLT purposes, especially if it does not comply with the relevant legal framework and does not specifically mention SDLT.

There are two separate consequences if the authority is defective:

• the SDLT return may not be validly signed by the attorney, and
• HMRC may refuse to discuss the return or disclose information to the supposed attorney because of confidentiality rules.

So this is not just about formality. It affects whether the filing can be made properly and whether HMRC will deal with the representative at all.

How to analyse it

If an attorney is expected to sign or submit an SDLT return, the sensible questions are:

• Who is the purchaser for SDLT purposes?
• Who is actually making the declaration in the return?
• What is the legal source of that person’s authority?
• Is the power of attorney valid under the relevant law?
• Does the document clearly authorise the attorney to deal with SDLT matters, not just the purchase or mortgage generally?
• If HMRC needs to discuss the return, is there a proper legal basis for HMRC to disclose confidential information to that person?

Where the document is a standard lender form or mortgage condition, it is important not to assume that the heading “Power of Attorney” settles the issue. The substance matters. HMRC’s view is that many such clauses are not enough.

If there is doubt about validity, the source material indicates that a court order may sometimes be used to rectify the position. But unless and until that happens, HMRC may treat the authority as insufficient.

Example

A buyer is purchasing a property with a mortgage. The lender’s standard mortgage terms say that the lender may act as the buyer’s attorney for matters connected with the loan and security. The terms do not mention SDLT, and the clause does not satisfy the legal requirements for a valid power of attorney under the relevant law.

The lender’s agent signs and files the SDLT return on the buyer’s behalf.

On HMRC’s approach in the source material, that is not enough. HMRC may say the buyer did not validly authorise the agent to deal with SDLT, so only the buyer could sign the declaration. HMRC may also refuse to discuss the return with the lender or its agent because taxpayer information is confidential.

If a court later makes an order rectifying the power and permitting disclosure, HMRC may then accept the position in line with that order.

Why this can be difficult in practice

The difficulty is that documents used in property transactions often give someone wide practical authority, but that does not necessarily mean they give the right legal authority for SDLT purposes.

There are also different legal routes mentioned in the source material depending on the jurisdiction and type of appointment. Validity is therefore not just a tax question. It may depend on the law governing powers of attorney or agency.

Another practical difficulty is that HMRC says it will “normally” expect SDLT to be referred to explicitly. That suggests a strong expectation, but it is still an administrative statement rather than a full statutory test set out in the manual. In practice, however, a document that does not expressly mention SDLT is likely to face difficulty with HMRC.

The confidentiality point can also catch people out. A person may think they are authorised to handle the transaction, but HMRC may still be unable to speak to them unless there is a proper legal mechanism allowing disclosure.

Key takeaways

• An attorney can sign an SDLT declaration only if the power of attorney is valid and covers SDLT matters.
• HMRC will normally expect the document to refer expressly to SDLT, rather than relying on general wording.
• Standard mortgage “power of attorney” clauses may be ineffective for SDLT and may not let HMRC disclose confidential taxpayer information.

This page was last updated on 24 March 2026

Useful article? You may find it helpful to read the original guidance here: Guidance on Powers of Attorney and SDLT Requirements for Land Transactions

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