Trusts and deceased estates need more than one authority. Access to a trust’s record on the Trust Registration Service comes only through a digital handshake from the agent services account after a trustee has claimed the trust, while dealing with the trust’s or estate’s tax returns needs a form 64-8 signed by a trustee or the personal representative. Registering an estate online for a client does not, on its own, give the agent authority to act.

Why do trusts and estates need separate authorisations?

HMRC runs several services for trusts and estates and each has its own gateway. The register of trusts, the Trust Registration Service, sits in the agent services account and uses the digital handshake. The trust’s Self Assessment return, form SA900, and correspondence about the trust’s tax are handled under the older agent authority given on form 64-8. HMRC’s own guidance is explicit that a 64-8 authority will not give the agent access to the Trust Registration Service online.

The same split applies to estates. HMRC’s table of authorisation methods lists the Trust Registration Service as handshake only, and Self Assessment as Online Agent Authorisation or form 64-8. An agent who has one but not the other will find they can update the register but not discuss the tax return, or the reverse.

The client is also different from an ordinary individual. For a trust it is the trustees, and HMRC’s registration guidance says all trustees are equally legally responsible for the trust but must nominate a lead trustee as HMRC’s main contact. For an estate it is the personal representatives. The general mechanics of the agent services account are covered in the agent services account and authorising an agent; this page deals with what is different for trusts and estates.

How does an agent get access to a trust on the Trust Registration Service?

Before an agent can view or change a trust’s registration online, a trustee must authorise them through the digital handshake, and before that the trustee must “claim” the trust. The Trust Registration Service Manual at TRSM92010 and TRSM92020 sets out the steps:

  1. The trustee sets up an Organisation Government Gateway user ID for the trust. An individual user ID cannot be used, and an ID already linked to another trust or to a personal tax account cannot be reused. If an agent originally registered the trust, the trustee needs a new organisation ID.
  2. The trustee claims the trust by answering security questions. The answers must match what HMRC holds from the registration or last update, so the agent should give the trustee the latest details first.
  3. Once the trust is claimed, the agent signs in to the agent services account, chooses the option to ask a client to authorise them, and enters the trust’s Unique Taxpayer Reference or Unique Reference Number to generate a request link.
  4. The agent emails the link to the trustee, saying which trust it relates to. Each trust needs its own link.
  5. The trustee signs in with the same organisation ID used to claim the trust and accepts the request. The link expires after 21 days.

Authorisation continues until the trustee or the agent removes it. A new authorisation replaces the existing one, so authorising a new firm automatically removes the old one. HMRC tells trustees to keep the agent’s email because the link in it may be needed to remove the agent later (TRSM92030).

What if the trustee cannot use online services?

A digitally excluded trustee can contact the Trusts Helpline for help with the handshake. The agent must request authorisation through the agent services account first, and the trustee must check that this has been done before calling. The helpline refers the case to HMRC’s Extra Support Team, which completes the authorisation with the trustee. In this route the trustee does not have to create a Government Gateway account or claim the trust (TRSM92040). Digitally excluded trustees also need to contact the Trusts Helpline to change or remove an agent.

How is an agent authorised for a trust’s tax affairs?

Form 64-8 covers individual, partnership and trust tax affairs. The notes on the form say that for a trust, one or more of the trustees signs it, and the trust section asks for the trust’s Unique Taxpayer Reference where one exists. HMRC’s paper forms guidance says a 64-8 for a trust’s tax affairs should go to the Trusts and Estates Team rather than the Central Agent Authorisation Team.

Because the 64-8 and the register authority are independent, a firm taking on a taxable trust usually needs both: the handshake to keep the register up to date and the 64-8 to deal with the SA900 and any correspondence about the trust’s income tax and capital gains. Client due diligence on trustees and beneficial owners is a separate obligation; see customer due diligence for trusts and charities.

How does authorisation work after a client dies?

Any authority the deceased gave ends on death, including a 64-8, so the firm that acted for the client in life has no standing until the personal representatives authorise it afresh; the practical consequences are covered in dealing with a deceased client. HMRC’s paper forms guidance says personal representatives can use form 64-8 to authorise an agent to deal with the deceased’s individual PAYE, Self Assessment and National Insurance. The personal representative signs and dates the form with their own name and address, and enters the deceased’s National Insurance number or Unique Taxpayer Reference in the relevant section. The returns themselves are covered in a tax return for someone who has died.

What about the estate’s own tax during administration?

Only some estates need to be registered for their own tax during administration. HMRC’s guidance for agents says registration is needed only if the estate is worth more than £2.5 million, assets sold by the personal representatives in any one tax year exceed £500,000, or the total tax due exceeds £10,000. Other estates with tax to pay can use the informal payment arrangements instead; the tax rules are covered in estate income and gains in administration.

Where registration is needed, it must be done by 5 October after the tax year in which the estate starts to receive income or has chargeable gains on which tax is payable. An agent registers the estate through the agent services account. HMRC then sends the estate’s Unique Taxpayer Reference to the personal representative, usually within 15 working days.

The trap is that registering the estate does not authorise the agent. HMRC’s guidance states that registering a client’s estate does not give the agent authority to act, and that HMRC needs a form 64-8 before it will communicate with an agent acting for a personal representative.

Viewing or changing the estate’s registration details later uses the same pattern as trusts: the personal representative sets up an Organisation Government Gateway user ID, claims the estate by answering questions that must match HMRC’s records, and then accepts the agent’s request link, which the agent generates from the estate’s Unique Taxpayer Reference.

How might this work in practice?

Illustration only. A practice is engaged by the executors of a client who died in June. The estate includes a let property and shares the executors expect to sell for about £600,000 in the first tax year of administration, so the £500,000 sale threshold is crossed and the estate must be registered. The practice registers the estate through its agent services account and diarises the 5 October deadline. Separately, it sends a 64-8 signed by an executor so that HMRC will discuss the estate’s return with it, and a second 64-8, signed by the executor using the deceased’s National Insurance number, for the deceased’s final Self Assessment. When the will trust later becomes a taxable trust, the trustees claim it on the register and accept the firm’s handshake link, and one trustee signs a further 64-8 for the SA900.

What mistakes come up most often?

  • Assuming the 64-8 held for the deceased still works after death.
  • Treating estate registration as authority to act and then finding HMRC will not speak to the firm.
  • Relying on a 64-8 to update the Trust Registration Service, or on the handshake to deal with the SA900.
  • Sending the trustee a handshake link before they have claimed the trust, or giving out of date details so the claim fails.
  • Asking the trustee to use their personal tax account sign in, which cannot be used to claim a trust.
  • Letting the 21 day link expire without following up.
  • Forgetting that authorising a new agent on the register removes the previous one, which can cut off a firm still handling part of the work.

Solar Protect runs fee protection schemes for accountancy and bookkeeping practices. See how our accountant schemes work or read fee protection schemes for accountants.

Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.