We’ll walk you through what people mean by an “HMRC trust tax number” and why there are actually two possible references you might receive after registration.
After you register on the Trust Registration Service (TRS), HMRC issues either a Unique Reference Number (URN) for non-taxable trusts or a Unique Taxpayer Reference (UTR) for taxable trusts. The reference identifies the trust arrangement in all official correspondence with HMRC.
This guide is for trustees and families in England and Wales who manage trusts as part of their estate planning. We set clear expectations on timing: you receive the reference only after TRS registration is processed, not before.
We’ll keep the steps practical and jargon-light. You’ll learn how the reference fits into day-to-day trust administration, what to watch for with Government Gateway access and identity matching, and why it matters that you don’t misplace the HMRC letter when it arrives.
Key Takeaways
- Registration on the TRS triggers an official reference from HMRC — either a URN or a UTR.
- A URN identifies non-taxable trust arrangements; a UTR (ten digits) is issued where the trust has a tax liability and HMRC expects Self Assessment returns.
- Keep the letter safe — your solicitor, accountant and fellow trustees will all need the reference.
- Common hurdles include Government Gateway login issues and identity details not matching the TRS record.
- All UK express trusts must be registered on the TRS within 90 days of creation, and the register must be kept up to date as an ongoing obligation.
What an HMRC trust tax number is and when you’ll receive it
Once HMRC has processed your TRS submission, they’ll send a formal letter to the lead trustee confirming which identifier applies to the trust arrangement. The type of reference you receive depends on whether the trust has any tax liability.
A URN (Unique Reference Number) is a 15-character alphanumeric code that identifies a non-taxable trust arrangement on the TRS. A UTR (Unique Taxpayer Reference) is a ten-digit code issued when the trust has a tax liability — meaning HMRC expects the trustees to file a Self Assessment Trust and Estate Tax Return (SA900) each year.
How the Trust Registration Service supports anti-money laundering checks
The TRS was introduced to comply with the 4th and 5th EU Anti-Money Laundering Directives (now retained in UK law following Brexit). It requires trustees to declare who the settlor is, who the trustees and beneficiaries are, and what assets the trust arrangement holds. This transparency helps HMRC and other authorities verify who controls trust assets. Since 6 October 2020, virtually all UK express trusts — including non-taxable ones — must register. Importantly, the TRS register is not publicly accessible (unlike Companies House), so your family’s details remain private. This is one of the key advantages of a trust arrangement — it allows families to plan effectively without their financial affairs becoming a matter of public record.
When you must register and remain registered
All UK express trusts must register on the TRS within 90 days of creation, regardless of whether they have a tax liability. This includes discretionary trusts, bare trusts, and interest in possession trusts — the three main types of trust arrangement used in English and Welsh estate planning. Some trusts are exempt from registration — such as certain pension trusts, life insurance policy trusts that pay out on death only, and charitable trusts already registered with the Charity Commission. Once registered, the obligation is ongoing: you must update the record within 90 days of any change and confirm the details remain accurate each year for taxable trusts.
| Identifier | Applied when | Main action once issued |
|---|---|---|
| URN | Trust arrangement is non-taxable | Keep the letter securely for records and share with your solicitor |
| UTR (10 digits) | Trust arrangement has a tax liability | Use for SA900 tax returns and to authorise an agent (solicitor or accountant) |
| TRS confirmation | After submission is accepted by HMRC | Update details within 90 days of any change |
Plain reminder: registering is not a one-off task. Trustees have an ongoing legal obligation to keep TRS records current and to check for required updates. Failing to do so can result in penalties of up to £5,000 for deliberate non-compliance. As we say at MP Estate Planning — plan, don’t panic. Getting these foundations right from the start makes the ongoing administration far simpler.
What you need before you start trust registration on the TRS
Before you begin, gather all the necessary details so you can complete the registration in one sitting. Having everything ready prevents frustrating re-starts and incomplete submissions. Think of it like preparing for a doctor’s appointment — going in with all your information means you get through the process smoothly the first time.
Lead trustee role and access
The lead trustee is the only person who can claim and manage the trust’s online TRS record. All trustees remain jointly and severally responsible for the trust’s administration, but the lead trustee acts as HMRC’s main point of contact and controls the TRS entry. Remember that a trust arrangement requires a minimum of two trustees — you cannot administer a trust alone. Choose a lead trustee who is reliable, accessible, and comfortable using online services. It’s worth noting that the settlor (the person who created the trust) can also be a trustee, which is common in family estate planning as it keeps the settlor involved in the trust’s management.
Information to gather for people involved
You’ll need personal details for every person connected to the trust arrangement: all trustees, the settlor (the person who created the trust), and the beneficiaries. This includes full legal name, date of birth, nationality, country of residence, and contact details.
Where possible, include a National Insurance number for UK residents or passport details for non-UK residents. If a beneficiary or settlor lacks mental capacity, you may need to complete a Vulnerable Person Election (VPE1) form to protect their information from wider disclosure. In such cases, it’s also worth checking whether a Lasting Power of Attorney (LPA) is in place for the person who lacks capacity, as this may affect how their affairs are managed in relation to the trust.
Core trust details you will be asked for
Prepare the trust name (as stated in the trust deed), the date the trust was created, and its type — for example, whether it is a discretionary trust (where trustees have absolute discretion over distributions to beneficiaries), a bare trust (where the beneficiary has an absolute right to the capital and income once they reach 18), or an interest in possession trust (where a life tenant receives income or use of the trust property). You’ll also need to answer questions about the trust’s assets.
Note the specific question about whether the trust acquired land or property in the UK since 6 October 2020. The TRS also asks whether the trust arrangement is administered in any other country, so check your trust deed for any relevant details. Having the trust deed to hand throughout the registration process is essential — it contains all the key information HMRC will ask about.
Government Gateway basics
Set up a Government Gateway account using a valid email address, your name and a secure password. When asked what type of account you need, choose Organisation — this is essential when acting for a trust arrangement.
That choice links the gateway account to the TRS correctly and avoids access issues later when you need to add agents or authorise an accountant to act on the trust’s behalf. For sign-in help, see the official guidance on registering as a trustee or read our advice for agents at registering as an agent.
| Item | Why it matters | Examples |
|---|---|---|
| Lead trustee details | Main contact and sole manager of the online TRS record | Full name, email address, Government Gateway organisation account |
| Personal details for all parties | Identity checks and matching against HMRC records | Date of birth, National Insurance number or passport, current address |
| Trust details from the trust deed | Determines the registration route and tax obligations | Trust name, date created, trust type (discretionary, bare, etc.), property held |
| Mental capacity note | Protects vulnerable beneficiaries’ personal information | VPE1 form if a settlor or beneficiary lacks mental capacity |
How to get your HMRC trust tax number through the Trust Registration Service
Registering your trust arrangement on the GOV.UK Trust Registration Service is a clear, step-by-step process that ends with an official letter from HMRC to the lead trustee containing the reference number.
Registering the trust on GOV.UK via the Trust Registration Service
Sign in with your Government Gateway organisation account. Follow the on-screen questions about the lead trustee, the other people connected to the trust arrangement (settlor, other trustees, beneficiaries), and the core trust details from the trust deed. Save or print a copy of your submission for your records — it helps enormously if you need to check details later or if queries arise.
What happens after registration and how HMRC issues the URN or UTR letter
After you press submit, HMRC processes the entry and posts a letter to the lead trustee’s registered address. The letter contains either a URN — a 15-character alphanumeric code for non-taxable trust arrangements — or a UTR — a ten-digit code for taxable trust arrangements where HMRC expects annual Self Assessment returns. Processing times vary, but you should typically receive the letter within a few weeks of submission. Keep the reference safe; it is the key identifier for all future correspondence with HMRC, banks, solicitors and accountants.
Keeping your URN or UTR safe for future HMRC correspondence
Store the postal letter securely. Scan a copy and save it in a password-protected folder on your computer or cloud storage. Give your solicitor or financial adviser a copy so they can act without delay if you misplace the original. If a fellow trustee needs the reference for administration purposes, share it directly rather than leaving it to memory. It’s good practice to store the reference alongside the trust deed itself, so all key trust documents are kept together.
For a wider guide on setting up and managing a UK trust arrangement, see our guide to unlocking the benefits of a UK trust.
How the lead trustee can claim and manage a trust already registered
Claiming an already-registered trust arrangement links the lead trustee to the existing TRS record so they can update details and act on behalf of all the trustees. This situation commonly arises when the original lead trustee has passed away, lost capacity, or retired from the role. Only the lead trustee may make this claim on the TRS, so having the right documents ready before you start saves time and avoids lockouts.
Accessing the correct GOV.UK page and signing in
Go to the “Manage your trust’s details” page on GOV.UK and choose to sign in with a Government Gateway organisation account. Use the same gateway credentials that were created when the trust was first registered. If the original lead trustee has changed and you are now taking over, you’ll need to go through the claiming process as the new lead trustee — this is a separate process from simply signing in.
Passing the TRS security checks with matching identity details
Have the lead trustee’s full legal name, date of birth and National Insurance number ready. The TRS requires exact matches to the details already on record — even a slight difference in name spelling or an old address can cause a mismatch. You will also need the details of at least one other person linked to the trust arrangement (such as the settlor or another trustee) for additional verification.
Linking the URN/UTR and confirming an agent
Enter the URN or UTR from the official HMRC letter to link the existing record to your Government Gateway account. The system then asks whether an agent — for example, a solicitor or accountant — will help manage the TRS record. Confirming an agent authorises them to access and update the trust’s TRS details on your behalf, which is particularly helpful if your trust arrangement holds property or investments that generate taxable income requiring professional management.
Common lockouts and errors to avoid
Check spellings carefully, including any historic addresses and old personal data that may still be on the record. Three failed identity-matching attempts will lock your access for 30 minutes, so take your time and double-check every entry before submitting. Common pitfalls include missing middle names, using an abbreviated first name instead of the full legal name, or entering a previous address that doesn’t match the one HMRC holds. If you’re stuck, it’s worth contacting HMRC’s trusts helpline rather than burning through your login attempts.
| Step | What to have ready | Why it matters |
|---|---|---|
| Sign in | Government Gateway organisation account credentials | Connects you to the TRS “Manage your trust” page |
| Identity checks | Lead trustee’s name, DOB, National Insurance number, plus one other connected person’s details | Ensures the lead trustee is correctly matched to the existing record |
| Link record | URN or UTR from the HMRC letter | Links the online record to your Government Gateway account |
| Agent confirmation | Agent’s details if using a solicitor or accountant | Allows authorised professional advisers to access and update the record |
If you need extra help, see our short guide for trustees on how to claim and manage a TRS record at register a trust as a trustee. Prepare the details in advance, take your time with each screen, and you’ll avoid the most common pitfalls.
What to do after you have the number: updates, annual declarations and closing the trust
Receiving the official reference is just the beginning — it triggers a practical set of ongoing duties: keeping records updated, filing annual declarations for taxable trusts, and, when the time comes, properly closing the trust arrangement on the register.
Keep details current within 90 days
You must update the TRS within 90 days of any material change to the trust arrangement. This includes appointing or removing a trustee, adding or removing a beneficiary, a beneficiary reaching the age of entitlement (for example, turning 18 in a bare trust, at which point the beneficiary gains an absolute right to the trust assets under the rule in Saunders v Vautier), a change of lead trustee, or a change in the trust’s assets — such as acquiring or disposing of property.
Make the update on the TRS and save or print a confirmation. That short record prevents confusion later and helps any solicitor or accountant who needs to access the trust’s details. It’s also good practice for trustees to keep a separate trust administration diary noting key dates — including TRS update deadlines, 10-year anniversary dates for periodic charges on discretionary trusts, and the annual SA900 filing deadline.
Annual declarations and the tax year
For trust arrangements with a UTR (taxable trusts), trustees must file a Self Assessment Trust and Estate Tax Return (SA900). The UK tax year runs from 6 April to 5 April, and the filing deadline is 31 January following the end of the tax year — so for the 2024/25 tax year, the SA900 is due by 31 January 2026.
Even if the trust had no income or gains in a particular year, you should still check whether a nil return or declaration is required. Submitting on time keeps the register compliant and avoids unnecessary query letters or late-filing penalties from HMRC. Late filing can also attract daily penalties that accumulate quickly, so it’s always better to file early and keep everything clean.
Penalties for failing to update
Trustees have a legal obligation to keep the TRS record accurate and up to date. Deliberate failure to register, update or maintain the record can lead to penalties of up to £5,000. Even where the failure isn’t deliberate, HMRC may still impose penalties for careless or late submissions. In plain terms: the cost of keeping things current is minimal compared to the potential fines and complications of letting it slip. When you consider that a trust arrangement can last up to 125 years under English and Welsh law, building good habits from the start is essential.
When you may also need a tax return
If the trust has taxable income (for example, rental income from property held in the trust) or chargeable capital gains, the trustees must file an SA900 Trust and Estate Tax Return in addition to any TRS declarations. Trust income is taxed at 45% for non-dividend income (39.35% for dividends), with the first £1,000 taxed at the basic rate. Capital gains within the trust are taxed at 24% for residential property and 20% for other assets, with the annual exempt amount currently set at half the individual level. If you’re unsure whether a return is needed, seek advice from a solicitor or accountant experienced in trust taxation — the law, like medicine, is broad, and using a specialist makes all the difference.
Closing and deregistering once assets are distributed
Once the trust has been fully wound up and all assets have been appointed out to beneficiaries, the lead trustee should close the TRS record. Log in to the “Manage your trust’s details” page, select “Close the trust”, enter the closure date (the date the final assets were distributed), and confirm the details are accurate. Note that when assets are appointed out of a discretionary trust, holdover relief may be available so that no immediate capital gains tax charge arises — but this should be confirmed with your solicitor or accountant before the distribution takes place.
Save or print the deregistration confirmation and share it with your solicitor or adviser. This document provides evidence that the trust has been properly closed, which may be needed if questions arise in the future — for example, during a beneficiary’s own tax return or if HMRC queries the trust’s status.
Need a refresher on how to manage the register online? See the official GOV.UK guidance for step-by-step help: manage your trusts registration service.
Conclusion
As a final note, small habits — accurate entries, safe storage and prompt updates — prevent most of the delays and penalties that catch trustees out.
To recap the journey: complete TRS registration, receive the official URN or UTR reference from HMRC, then claim and manage the record as the lead trustee on an ongoing basis. Keep copies of the HMRC letter, details of all connected parties, and important dates (trust creation date, 10-year anniversary dates for periodic charges on discretionary trusts, and the 31 January filing deadline) in a secure place.
The key habits to follow are straightforward. Enter clear, accurate information that matches existing HMRC records. Save digital and physical copies of all confirmations. Act within the 90-day window whenever details change. These steps keep families out of trouble and make trust administration far more manageable than many people expect. England invented trust law over 800 years ago — the systems are well established, and with the right approach, managing the administrative side is entirely within reach for ordinary families.
If you need help, use the official GOV.UK guidance or contact the HMRC trusts helpline on 0300 123 1072 (from abroad +44 300 123 1072). You can also write to HMRC at Trusts, BX9 1EL, or use the online assistant.
Need a fuller walkthrough? See our step-by-step guide to registering a trust in Britain to move forward with confidence.