Guidance on Completing SDLT Forms and Local Authority Codes

SDLT Paper Returns and the Local Authority Code

When you file an SDLT return on paper, you must enter a valid local authority code for the lead property or HMRC may reject the return. This rule applies to paper forms SDLT1, SDLT3 and SDLT4. The code does not affect the amount of tax due, but it does affect whether HMRC will accept the form for processing.

• The code must match the local authority area where the lead property is situated.
• If a property crosses two local authority areas, either code can be used, but HMRC prefers the one covering most of the property.
• For late notifications, use the authority code that applied at the effective date of the transaction, even if the authority has since been renamed, merged or abolished.
• HMRC’s list may include old or obsolete authority names because historic codes may still be needed for older transactions.
• This guidance is only for SDLT paper returns and does not apply to Scottish LBTT or Welsh LTT transactions.

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SDLT paper returns: how to complete the local authority code field

This page explains the local authority number that must be entered on certain Stamp Duty Land Tax paper forms. Although it is only one box on the form, it matters because HMRC says a paper return will be rejected if it does not contain a valid code. The point mainly affects paper form SDLT1, but the same guidance also applies to SDLT3 and SDLT4.

What this rule is about

When an SDLT return is filed on paper, HMRC requires the filer to identify the local authority area for the property. On form SDLT1 this is question 29. Online, it is shown as 1.29. The same approach applies to question 2 of SDLT3 and question 10 of SDLT4.

The rule is administrative rather than a tax charging rule. It does not determine how much SDLT is due. But it does affect whether HMRC will accept the return for processing.

The guidance is also framed by the fact that SDLT no longer applies to land transactions in Scotland from April 2015, and does not apply to Welsh land transactions from 1 April 2018, because those are instead subject to LBTT in Scotland and LTT in Wales.

What the official source says

HMRC states that, from 1 October 2014, anyone filing a paper SDLT1 must enter a valid local authority code. If the return does not include a valid code, HMRC will reject it.

The code required is the number for the local authority in whose area the lead property is situated.

If the property crosses a local authority boundary, HMRC says you may use the code for either authority, though preferably the one covering most of the property.

HMRC’s list includes some authorities that no longer exist. The reason given is that some transactions are notified late, so the code used should reflect the authority that was appropriate at the effective date of the transaction.

HMRC also says that where local government areas have since merged or been reorganised, and the new authority does not appear in the list, you should use the code for the authority that existed before the change.

What this means in practice

If you are completing a paper SDLT return, you should not treat the local authority box as optional or minor. HMRC’s position is that the return must contain a valid code or it will be rejected.

The practical steps are:

• identify the lead property for the transaction
• work out which local authority area that property is in
• find the matching code from HMRC’s list
• if the property spans two authority areas, choose either code, preferably the one covering most of the property
• if the authority has changed since the transaction date, consider the authority that applied at the effective date

This matters particularly for older transactions notified late. HMRC’s list deliberately includes obsolete authority names and codes so that the return can reflect the position at the relevant time, not just the current map of local government.

It also means you should be careful not to substitute a modern authority name if HMRC’s list instead expects the predecessor authority code.

How to analyse it

A sensible way to approach the field is to ask the following questions.

• Is this an SDLT return at all? If the land is in Scotland or, from 1 April 2018, in Wales, the transaction may fall under LBTT or LTT instead of SDLT.
• Is the return being made on paper? This guidance is specifically about paper forms SDLT1, SDLT3 and SDLT4.
• What is the lead property? The code must relate to the lead property, not necessarily every parcel involved in the transaction.
• Which local authority area was the lead property in at the effective date of the transaction?
• Has the authority since been abolished, merged or renamed? If so, HMRC’s guidance indicates that the earlier authority code may still be the correct one.
• Does the property cross a boundary? If yes, either authority’s code may be used, though HMRC prefers the authority covering most of the property.

The key point is that the code is tied to location and timing. Current local authority geography is not always the decisive factor if the transaction is being notified late.

Example

Illustration: a buyer files a paper SDLT1 late for a transaction whose effective date was several years ago. Since then, the local authority structure has changed and the old district council no longer exists. HMRC’s guidance indicates that the filer should use the code for the authority that applied at the effective date, if that is how the authority appears in HMRC’s list.

Illustration: a large property extends over two local authority areas. HMRC says either code can be entered, but the preferred code is the one for the authority covering most of the land.

Why this can be difficult in practice

The main difficulty is that this is an old administrative coding system overlaid on changing local government boundaries and names. A filer may know the current council area, but HMRC may expect the historic code if the transaction is being notified late.

Another difficulty is identifying the lead property where a transaction involves more than one property. The source material assumes that the filer can identify which property is the lead property, but it does not explain that concept on this page.

Boundary issues can also be awkward. HMRC allows either code where a property straddles two authority areas, which is helpful, but the filer still needs enough information to know that the property genuinely crosses the boundary and which authority covers most of it.

Finally, the guidance is specifically about SDLT forms. It should not be carried across to Scottish or Welsh land transaction taxes, which have their own systems.

Key takeaways

• On a paper SDLT1, the local authority code is mandatory and HMRC says the return will be rejected without a valid code.
• The code should be for the local authority area of the lead property, using the authority relevant at the effective date if the transaction is notified late.
• If the property crosses a boundary, either authority’s code may be used, though HMRC prefers the one covering most of the property.

This page was last updated on 24 March 2026

Useful article? You may find it helpful to read the original guidance here: Guidance on Completing SDLT Forms and Local Authority Codes

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