Main and supporting agents under MTD

Under Making Tax Digital for Income Tax a client can have one main agent and any number of supporting agents. A supporting agent can sign the client up, keep the business and property records and send quarterly updates, but cannot see the client’s other income, view the tax calculation, finalise the year or submit the tax return. Those end of year tasks belong to the main agent or the client.

Why does MTD have two kinds of agent?

Traditional Self Assessment allows one agent per client for each tax service. Quarterly reporting changes the workload: a bookkeeper may handle the records all year while an accountant prepares the year end position. HMRC’s small business review, published after Autumn Statement 2023, committed to letting MTD customers be represented by more than one agent so that quarterly updates could be done by one agent and the end of year work by another. HMRC’s guidance on choosing agents now gives the result: a main agent and supporting agents, with different access.

The multiple agent model applies only to Making Tax Digital for Income Tax. For other services, such as Self Assessment, a client can still have only one agent, and different agents can be appointed for different taxes.

What combinations of agents are allowed?

HMRC’s guidance says a sole trader or landlord can:

• have only one main agent at a time, but any number of supporting agents;
• have a main agent without any supporting agents;
• have supporting agents without a main agent.

A firm can be a main agent for some clients and a supporting agent for others. Appointing another supporting agent does not remove the existing main agent or other supporting agents. Appointing a new main agent does: the previous main agent loses access, and HMRC places the responsibility for telling the old firm on the client. Where a client has supporting agents but no main agent, the client has to submit the tax return personally, because a supporting agent cannot.

What can a supporting agent do, and what can it not do?

The table below summarises HMRC’s comparison of tasks in its choose agents guidance.

Task	Main agent	Supporting agent
Sign a client up, or opt them out	Yes	Yes
Add or cease sole trader and property businesses	Yes	Yes
Contact HMRC about the sole trader and property businesses	Yes	Yes
Change to calendar update periods using software	Yes	Yes
Complete and submit quarterly updates	Yes	Yes
View due dates and all quarterly update totals	Yes	Yes
View National Insurance number and UTR	Yes	Yes
Contact HMRC about current and previous tax returns	Yes	No
View all income sources, and view or amend non business income	Yes	No
View the tax calculation and amounts owed and paid	Yes	No
Finalise the tax position, submit the return and amendments	Yes	No
Request a repayment, or adjust payments on account	Yes	No
Tell HMRC a client no longer needs to file a return	Yes	No
Receive copies of statutory communications and penalty notices, and appeal penalties	Yes	No
Set up a Direct Debit, or change contact preferences	No	No
See details of other agents on the client’s record	No	No

A supporting agent sees the client’s personal details only where the client trades under their own name or uses a private address as the business address. Neither type of agent can see who else is authorised, so the firms have to tell each other.

Can a supporting agent be limited to one business?

No. HMRC says that if a client authorises several supporting agents, it cannot restrict their access and permissions to a single business. A bookkeeper engaged only for a client’s rental properties can still see and update the client’s trade figures in HMRC’s systems. The limit therefore has to be contractual: the engagement letter should say which income sources each firm handles. Our page on engagement letters for accountants covers scope wording.

How do the agents avoid sending conflicting figures?

HMRC requires that where several agents work on the same business, one combined update is sent for each update period, and one submission is made for the tax return after any adjustments. The unit is the business, not the property or the client:

• all UK property income counts as one business;
• all foreign property income counts as another business;
• each separate trade is its own business.

Two firms can therefore each send quarterly updates for the same client only if they deal with different businesses, for example one handles the trade and the other the UK property business. HMRC’s software guidance also says only one software product can be used for each separate submission, and recommends checking that the chosen software allows multiple agents.

Who does the year end work?

Only the main agent can submit the client’s tax return. HMRC’s guidance on submitting the return says the main agent can view quarterly updates sent by the client or a supporting agent in its software, but cannot view their digital records. A main agent who finds an error must correct the information before submitting.

Software used only to submit the return does not have to be digitally linked to the software used for records and quarterly updates, because it takes the data from HMRC. This lets an accountant use different software from the bookkeeper. Year end adjustments are usually made by changing category totals, and HMRC notes an agent may adjust this way and ask the client to update the underlying records. The digital link rules are covered in digital links under Making Tax Digital, and the year end process in the MTD final declaration.

How does a firm become a supporting agent?

The firm needs an agent services account and asks the client to authorise it through that account, choosing the supporting agent option so the client sees the right consent statement. Adding existing Self Assessment authorisations by agent code always produces main agent status, so it is not a route to supporting agent status. Either the firm, through “Cancel a client’s authorisation” in its agent services account, or the client, through its tax account, can end the authorisation. The account and sign up steps are set out in signing up clients for MTD Income Tax.

What does a typical split look like?

Illustration only. Priya runs a café as a sole trader and lets two flats. Her bookkeeper is authorised as a supporting agent and her accountant as main agent.

• The bookkeeper keeps digital records for the café and the flats and sends the quarterly updates for both businesses by 7 August, 7 November, 7 February and 7 May.
• The accountant reviews the cumulative totals, makes adjustments such as disallowing private phone use, adds Priya’s bank interest and dividends, checks the calculation and submits the return.
• Penalty letters go to Priya and the accountant, not the bookkeeper. If an update is late, the accountant has to tell the bookkeeper.

What mistakes should firms avoid?

• Assuming a supporting agent can see the tax calculation to answer a client’s question about the bill. It cannot.
• Two firms sending updates for the same business in the same period.
• Relying on HMRC to restrict a supporting agent to one business.
• Not agreeing who receives and acts on penalty notices, which supporting agents do not get.
• Accepting main agent status by adding an agent code when the client meant the firm to be a supporting agent, which removes the existing main agent.

Penalty points under MTD are covered in our HMRC penalties table.

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

Related Accountapedia entries

• When clients submit their own MTD quarterly updates
• Updating engagement letters for MTD Income Tax
• MTD late submission penalty points for agent clients
• Pricing MTD Income Tax quarterly work
• Copying authorisations into the agent services account

Sources

• GOV.UK: Making tax digital small business review outcome
• GOV.UK: Choose agents for making tax digital for income tax
• GOV.UK: Choose the right software for making tax digital for income tax
• GOV.UK: Submit your tax return
• GOV.UK: Create digital records
• GOV.UK: Add your client authorisations for making tax digital for income tax
• GOV.UK: Penalties for making tax digital for income tax

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.