Guidance on Completing SDLT1 Questions 49-51 for Individuals and Non-Individuals

Completing SDLT1 Questions 49 to 51

Questions 49 to 51 on the SDLT1 return are used to identify the purchaser, so the correct reference must be entered in the correct box. The answer depends on whether the lead purchaser is an individual or a non-individual such as a company or partnership. Mistakes can delay processing, cause rejection of the return, and may not always be capable of later amendment.

• For an individual lead purchaser, use question 49 for a valid National Insurance number and include the date of birth; if there is no National Insurance number, leave question 49 blank and use question 51.2 instead.
• If question 51.2 is used for an individual, enter a non-UK tax reference, or if none exists, a passport, driving licence or ID card number, and complete question 51.3 with the issuing country.
• For a non-individual purchaser, use either question 50 or question 51, not both; question 50 is for a VAT registration number, and if there is none, move to question 51.1.
• Question 51.1 must contain the 10-digit HMRC-issued company or partnership UTR, not a Companies House registration number; using the registration number there may lead to rejection.
• If a non-individual has no VAT number and no UK UTR, use question 51.2 for a Companies House registration number or non-UK tax reference, and always complete question 51.3 with the issuing country.
• Before filing, confirm who the lead purchaser is and check all reference details carefully, as HMRC treats VAT numbers, UTRs and company registration numbers as different identifiers for different fields.

Scroll down for the full analysis.

How to complete SDLT1 questions 49 to 51 correctly

This page explains how to fill in the identity and reference number questions on an SDLT return. These questions matter because HMRC uses them to identify the purchaser and process the return. If the wrong type of reference is entered, or the details are inconsistent, the return may be rejected or may need to be replaced with a fresh return.

What this rule is about

Questions 49, 50 and 51 on form SDLT1 ask for a unique identifying reference for the purchaser. The right answer depends mainly on whether the purchaser is an individual or a non-individual, such as a company or partnership.

The purpose is administrative rather than substantive. It does not decide whether SDLT is due. But it can affect whether HMRC can process the return smoothly and whether the filing is accepted without delay.

The source material also makes an important practical point: these details need to be accurate, and it may not be possible to amend them later. In some cases, an error may mean sending in a fresh return.

What the official source says

HMRC’s guidance draws a clear distinction between individual purchasers and non-individual purchasers.

For an individual purchaser:

• Question 49 should be completed if the lead purchaser is an individual who has a National Insurance number.
• The National Insurance number must be the correct one for the lead purchaser. HMRC says not to use a temporary number.
• If question 49 is completed, the lead purchaser’s date of birth should also be given.
• If the lead purchaser does not have a National Insurance number, question 49 should be left blank, including the date of birth field, and the filer should instead go to question 51.2.
• Question 51.2 is only used if question 49 has not been answered. It should contain a non-UK tax reference, or if there is none, a passport number, driving licence number or ID card number.
• If question 51.2 is used, question 51.3 must also be completed with the country that issued the reference.

For a purchaser that is not an individual:

• You should answer either question 50 or question 51, but not both.
• Question 50 is for a VAT registration number, if there is one.
• HMRC says a valid VAT registration number should be 9 digits, contain no letters, and not start with 00.
• If there is no VAT registration number, leave question 50 blank and go to question 51.1.
• Question 51.1 is for a UK company UTR or UK partnership UTR, depending on the purchaser.
• HMRC says this must be the HMRC-issued 10-digit UTR, not the Companies House company registration number.
• If a company registration number is entered in question 51.1, HMRC says the form will be rejected.
• If there is no company or partnership UTR, go instead to question 51.2.
• Question 51.2 is then used for a Companies House company registration number, or if there is none, a non-UK tax reference.
• If question 51.2 is used, question 51.3 must also be completed with the country that issued the reference.

What this means in practice

The practical task is to identify the purchaser correctly and then give the right kind of identifier in the right box.

The main mistakes HMRC is trying to prevent are:

• using an identifier meant for a different type of purchaser
• completing more than one route when only one should be used
• putting a Companies House company registration number where a UTR is required
• using question 51.2 when question 49 or 51.1 should have been used
• omitting the issuing country when question 51.2 is used

In practice, this means the person filing the return should not treat these fields as interchangeable. A company registration number, a VAT number and a UTR are different identifiers used for different purposes. Even if all of them relate to the same entity, they cannot simply be entered wherever there is space.

It also means that the filer should decide who the lead purchaser is before completing the form, because for individuals the National Insurance number and date of birth are required for the lead purchaser.

How to analyse it

A sensible way to approach these questions is as follows.

Step 1: Identify whether the lead purchaser is an individual.

• If yes, start with question 49.
• If no, use the non-individual route and consider question 50 or 51.

Step 2: For an individual, ask whether the lead purchaser has a National Insurance number.

• If yes, enter it in question 49 and include the date of birth.
• If no, leave question 49 blank and move to question 51.2.

Step 3: If question 51.2 is needed for an individual, decide what reference can properly be used.

• Use a non-UK tax reference if there is one.
• If not, use a passport number, driving licence number or ID card number.
• Then complete question 51.3 with the issuing country.

Step 4: For a non-individual, ask whether there is a VAT registration number.

• If yes, use question 50.
• If no, leave question 50 blank and move to question 51.1.

Step 5: If there is no VAT number, ask whether there is a UK company or partnership UTR.

• If yes, use question 51.1.
• Check that it is the 10-digit HMRC UTR, not the Companies House registration number.

Step 6: If there is no VAT number and no UTR, use question 51.2.

• For a company, this may be the Companies House company registration number.
• If there is no such number, use a non-UK tax reference.
• Then complete question 51.3 with the issuing country.

A useful cross-check is this: if you are about to enter a Companies House company registration number, it should not go in question 51.1. HMRC’s guidance is explicit on that point.

Example

Illustration 1: an individual buyer has a National Insurance number. The SDLT return should use question 49 for that number and include the buyer’s date of birth. Questions 51.2 and 51.3 should not be used for that buyer.

Illustration 2: a company buyer is not VAT-registered but does have a UK corporation tax UTR issued by HMRC. The return should leave question 50 blank and complete question 51.1 with the 10-digit UTR. The company registration number should not be entered in question 51.1.

Illustration 3: an overseas company buyer has no UK VAT registration number and no UK company UTR. In that case, question 51.2 should be used for the relevant non-UK tax reference, and question 51.3 should state the country that issued it.

Why this can be difficult in practice

The difficulty is usually not the legal rule itself, but identifying which reference HMRC wants in a particular field.

Several points can cause confusion:

• A company may have both a Companies House registration number and an HMRC UTR. They are not the same thing.
• Some purchasers, especially overseas purchasers or newly formed entities, may not have the reference that would normally be used, so the filer has to move to the fallback option.
• The guidance refers to the lead purchaser. In transactions with more than one buyer, the correct identification of the lead purchaser matters for the individual route.
• HMRC warns that these details may not be amendable later. That raises the practical importance of checking the source documents before submission.

The source material does not set out every possible edge case. For example, it does not fully explain what should happen if none of the listed identifiers is available. It simply says that help should be sought from the Stamp Taxes helpline.

Key takeaways

• Use the purchaser’s status first: individual purchasers follow question 49 or 51.2, while non-individual purchasers follow question 50 or 51.
• Do not confuse a company UTR with a Companies House registration number; putting the registration number in question 51.1 may cause rejection.
• If question 51.2 is used, question 51.3 must also be completed with the issuing country.

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 SDLT1 Questions 49-51 for Individuals and Non-Individuals

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