Main and supporting agents for MTD for Income Tax

The two roles

A main agent can manage everything for the client except setting up a Direct Debit or changing HMRC contact preferences. A supporting agent has limited access, sees business and property income details, and can do fewer tasks (HMRC: choose agents).

A client can have a main agent with no supporting agent, supporting agents with no main agent, or both. Where several agents work on the same business, HMRC says one combined update must be sent for each update period.

What each agent can do

Task	Main agent	Supporting agent
Sign the client up or opt them out	Yes	Yes
Contact HMRC about the sole trader or property businesses	Yes	Yes
Contact HMRC about current or earlier tax returns	Yes	No
View all Self Assessment income sources	Yes	No
Add or cease a business income source	Yes	Yes
View or amend non-business income	Yes	No
Choose and use software for business records	Yes	Yes
Choose and use software for the tax return	Yes	No
Change to calendar update periods	Yes	Yes
Complete and send quarterly updates	Yes	Yes
Send year-end adjustments for the businesses	Yes	Yes
Claim losses and reliefs	Yes	Yes, where that agent submitted the return
View tax calculations and amounts owed	Yes	No
Finalise the tax position and submit the return	Yes	No
Request repayments or adjust payments on account	Yes	No
Receive statutory letters and penalty notices	Yes	No
View and appeal penalties	Yes	No
View update and payment due dates	Yes	Yes
View quarterly totals	Yes	Yes
View National Insurance number and UTR	Yes	Yes
Set up a Direct Debit	No	No
View other agents' details	No	No

Getting authorised

Have an agent services account
HMRC's account guidance, updated 1 October 2026, asks for the firm's Government Gateway user ID, the firm's UTR and postcode, company and VAT numbers if any, and the name of the anti-money laundering supervisor with proof of supervision. HMRC rejects an application while supervision is still pending.
Bring Self Assessment clients across
Existing Self Assessment authorisations carry across to Making Tax Digital for Income Tax, and an agent with them is treated as main agent (HMRC: choose agents). Check each one appears in the agent services account and add any that do not (HMRC: sign up your client).
Ask new clients to authorise you
Sign in to the agent services account and follow the steps to request authorisation. The client sees a different consent statement for a main agent and a supporting agent.
Sign the client up
An agent who signs a client up is treated as their main agent (HMRC: choose agents).

One account per firm

HMRC's practice chapter of the agent toolkit says there should be one agent services account per firm, however many legacy agent accounts it has. The legacy Online Services for Agents account stays available alongside it. Software used for the service is authorised through the agent services account and the authorisation is renewed every 18 months.

HMRC's mandatory tax adviser registration also runs through the agent services account, with registration windows set by type of adviser.

Questions

Can a bookkeeper send updates while the accountant files the return?

Yes. One of HMRC's service examples has a bookkeeper as supporting agent keeping records and sending updates, with the main agent submitting the return.

Who receives penalty notices?

The main agent. A supporting agent cannot view or appeal penalties (HMRC: choose agents).

What happens to records when a client changes agent?

Digital records from earlier years do not move between agents automatically. The new agent must be authorised and have access to the records they need (HMRC: if your circumstances change).

Can a supporting agent see the client's name and address?

Only where the client uses their own name or private address as the business name or address, according to HMRC's table of agent tasks. A supporting agent can see the National Insurance number and UTR.

What must the main agent do before submitting the return?

Share the details of what will be submitted with the client and get their written confirmation before filing (HMRC: submit your tax return).

Can the main agent and a supporting agent use different software?

Yes, as long as the records are digitally linked and each submission goes through one product (HMRC: find compatible software). The agents agree which of them sends each period's combined update.

Does the 64-8 still matter?

For other taxes, yes. See agent authorisation and the 64-8 and the agent services account.

In Accountin

In Accountin, the Income tax tab records whether the practice is main or supporting agent, and only a main agent sees the calculation and final declaration, as HMRC allows.