Agent Authorisation for MTD Income Tax

How Your Accountant Signs Up for MTD on Your Behalf

Last updated: February 2026

Making Tax Digital for Income Tax requires quarterly digital submissions starting from 6 April 2026. Most sole traders and landlords will rely on their accountant or tax agent to handle this. But before your agent can submit anything to HMRC on your behalf, they need proper authorisation. This article explains exactly how agent authorisation works under MTD, what the Agent Services Account is, how existing 64-8 authorisations carry across, and what (if anything) you need to do as a client.

What is the Agent Services Account?

The Agent Services Account (ASA) is a separate HMRC online account that tax agents use specifically for newer digital services, including MTD for Income Tax. It sits alongside the older HMRC online services for agents account that your accountant already uses for Self Assessment, PAYE and other established services.

When your accountant creates an ASA, HMRC issues a new Government Gateway user ID. This is different from their existing credentials. Your agent ends up with two sets of login details: one for the traditional HMRC online services account, and one for the ASA. HMRC advises agents to keep careful records of which user ID belongs to which account.

Only a firm’s directors, partners or sole practitioners can create the ASA. They need their firm’s Unique Taxpayer Reference (UTR), their anti-money laundering supervisory body details, and their National Insurance number for identity verification. Once the ASA is set up, the firm can use it to manage MTD authorisations for all their clients.

How existing 64-8 authorisations transfer

If you have already signed a form 64-8 (the standard paper authorisation form) appointing your accountant as your tax agent for Self Assessment, that relationship can transfer into the ASA without any action from you.

Your agent copies existing Self Assessment authorisations into their ASA by signing in and selecting the option to add existing Self Assessment authorisations. The system works at the agent code level rather than individual client level. When your agent adds a Self Assessment agent code, every client linked to that code comes across in one step. Agents with multiple agent codes repeat the process for each one.

Key points about this transfer:

• It does not remove your agent’s access in the original HMRC online services account. Both accounts remain active.
• It does not automatically sign you up for MTD Income Tax. Your agent still needs to complete the sign-up process separately for each client.
• It does not require fresh consent from you. Your existing 64-8 authority carries across.
• Once linked, future changes to your Self Assessment agent authorisation sync automatically between both accounts.

HMRC has encouraged agents to start copying authorisations now, well ahead of April 2026, to avoid a bottleneck closer to the Phase 1 start date.

The digital handshake: authorising your agent online

If your accountant does not hold an existing 64-8 authorisation for you, or if you are a new client, a different process applies. This is the digital handshake.

The digital handshake works as follows:

1. Your agent sends a request. From within their Agent Services Account, your accountant initiates an authorisation request for MTD Income Tax. HMRC generates a unique link.
2. You receive the link. Your agent emails or sends you this link. It is valid for 21 days. If you do not respond within 21 days, your agent must generate a new one.
3. You sign in and accept. You click the link, sign in with your own Government Gateway credentials, and confirm that you authorise the agent. You may need to complete identity verification if this is your first time using your personal tax account.
4. The authorisation is live. HMRC confirms the link between your records and your agent’s ASA. Your agent can now sign you up for MTD Income Tax and submit quarterly updates on your behalf.

You must never share your Government Gateway sign-in details with your accountant. The entire point of the digital handshake is that you authenticate directly with HMRC yourself. Your agent does not need your password at any stage.

MTD authorisation is separate from Self Assessment authorisation

This is the part that catches people out. Being authorised to file Self Assessment returns for a client is not the same as being authorised for MTD Income Tax. They are treated as separate services within HMRC’s systems.

If your agent already has a 64-8 in place and has copied it to their ASA, the Self Assessment authorisation is recognised for MTD purposes. But if the relationship exists only as a digital handshake for Self Assessment (not copied from 64-8), your agent may need a separate MTD Income Tax authorisation. The safest approach is for your agent to check their ASA and confirm that MTD Income Tax authorisation appears against your name before attempting to sign you up.

HMRC has also introduced the ability for clients to authorise multiple agents. For example, you might have one accountant handling your quarterly updates and another providing tax advisory work. Each agent needs their own authorisation linked to their own ASA.

What you need to do as a client

In practice, the amount of action required from you depends on whether your agent already holds a 64-8:

If your agent has a 64-8 in place

You probably need to do nothing. Your accountant copies the authorisation to their ASA and then signs you up for MTD. You do not need to click any links, sign in to anything, or complete any forms. Your existing authority covers it.

If there is no 64-8 (new client or digital-only relationship)

You will need to complete the digital handshake. Your accountant will send you a link by email. You need to:

• Have a Government Gateway account linked to your Self Assessment record
• Click the link within 21 days
• Sign in with your own credentials
• Accept the authorisation request

If you do not already have a Government Gateway account, you will need to create one first. HMRC requires identity verification (typically your National Insurance number and a form of address confirmation). Allow a few days for this process if you are starting from scratch.

Practical steps your agent follows

For transparency, here is the full sequence your accountant works through to get you set up for MTD:

1. Create or access the ASA. If the firm does not yet have an Agent Services Account, a director or partner creates one at HMRC’s online portal.
2. Copy existing authorisations. The agent adds their Self Assessment agent codes to the ASA, pulling across all existing 64-8 client relationships.
3. Run the digital handshake for any clients without a 64-8 in place. The agent sends the authorisation link, waits for the client to accept, and confirms the link appears in their ASA.
4. Sign up the client for MTD ITSA. The agent uses their ASA credentials to access the MTD sign-up service on GOV.UK and enrols each client individually.
5. Connect MTD-compatible software. The agent links the client’s records in the chosen software to HMRC’s MTD systems, typically via an API connection.
6. Submit quarterly updates. From Q1 (6 April to 5 July 2026), the agent submits income and expense data through the software each quarter.

Steps 1 to 3 are the authorisation groundwork. Steps 4 to 6 are the operational MTD process. Your agent should be completing steps 1 to 3 now, before April 2026, so that the sign-up and software connection are ready when the first quarter begins.

Worked example: a sole trader with an existing accountant

David runs a plumbing business in Leeds. His gross self-employment income is £62,000 per year, so he falls into Phase 1 of MTD from 6 April 2026. He has used the same accountant, Marsh & Co, for eight years. Marsh & Co filed a 64-8 when David first became a client.

In January 2026, Marsh & Co set up their Agent Services Account. They add their Self Assessment agent code and all 340 of their clients, including David, transfer into the ASA automatically. David does not need to do anything at this stage.

In February 2026, Marsh & Co sign David up for MTD Income Tax through the GOV.UK sign-up service. They connect his records to Xero, set up bank feed connections for his business current account, and configure the quarterly reporting periods. David’s first quarter runs from 6 April to 5 July 2026. On 28 July 2026, Marsh & Co review his Q1 figures (£15,500 income, £4,200 expenses) and submit his first quarterly update, well within the 7 August deadline.

For the 2026/27 tax year, the soft-landing period means David will not receive penalty points even if a quarterly submission is late. But Marsh & Co still aim to submit on time every quarter, because the soft landing does not extend beyond 2026/27.

David’s only involvement is reviewing the figures his accountant shares with him before each submission. He does not need to log in to HMRC, use the software directly, or complete any forms. The authorisation was already in place from his original 64-8.

Common issues with agent authorisation

A few problems come up repeatedly:

• Client does not have a Government Gateway account. The digital handshake requires the client to sign in. If they have never created a Government Gateway account, they cannot complete the process until they do. This takes a few days if identity verification is needed.
• The 21-day link expires. Clients who ignore the authorisation email or delay acting on it will find the link has expired. The agent must generate a new one.
• Agent code not appearing in the ASA. If an agent’s Self Assessment agent code does not show when they try to copy authorisations, it usually means the code is not active or is registered under a different Government Gateway account. HMRC’s agent helpline can resolve this.
• Multiple agents for the same client. This is now supported. Each agent gets their own authorisation. One agent submitting quarterly updates does not affect another agent’s access.

Frequently asked questions

Do I need to sign a new 64-8 form for MTD Income Tax?

Not if your agent already has a 64-8 in place for Self Assessment. The existing authorisation transfers to the Agent Services Account. You only need the digital handshake if there is no existing 64-8 relationship.

Can my accountant sign me up for MTD without my involvement?

Yes, if they already hold a valid authorisation (either from a 64-8 or a completed digital handshake). They can sign you up and submit quarterly updates without you needing to log in or take any action. You should still review your figures before submission.

What if I change accountants after signing up for MTD?

Your new accountant will need their own authorisation. They can either file a 64-8 and copy it to their ASA, or send you a digital handshake link. Your old accountant’s access should be removed from both their ASA and the original HMRC online services account.

Does MTD agent authorisation cover VAT as well?

No. MTD for VAT authorisation and MTD for Income Tax authorisation are separate services within HMRC. Your agent needs authorisation for each one individually. Being authorised for one does not grant access to the other.

Is there a deadline to complete agent authorisation?

HMRC has not set a formal deadline for agent authorisation. However, if you fall into Phase 1 (qualifying income above £50,000), your first quarterly update is due by 7 August 2026. Your agent needs authorisation, sign-up and software all in place before that date. Starting the process now avoids a last-minute rush.

Sources

• GOV.UK: Get an HMRC agent services account
• GOV.UK: Sign up your client for Making Tax Digital for Income Tax
• GOV.UK: Add your client authorisations for Making Tax Digital for Income Tax
• GOV.UK: Authorise an agent to deal with certain tax services for you
• GOV.UK: Making Tax Digital for Income Tax