A main MTD agent can handle the overall annual-return role; supporting agents have narrower permissions for the work they are authorised to do. Agree who keeps the books, sends updates and finalises the return. Authorising another firm is not a substitute for that handover agreement.
What a main agent does
A main agent can manage the overall MTD tax position and submit the annual return. HMRC allows only one main agent at a time. Replacing that authorisation can affect the accountant who was previously responsible, so tell both providers about a planned change.
What a supporting agent does
A supporting agent can help with tasks such as digital records and quarterly updates, but cannot submit the annual MTD Income Tax return as your main agent. There can be more than one supporting agent, and their access is more limited.
Having someone authorised for quarterly work therefore does not establish that the annual return is covered. Check the engagement, the HMRC authorisation and the practical handover arrangements together.
Avoid two people filing overlapping figures
If several people work on the same business, HMRC requires one combined update for each update period. A bookkeeper should not send one version while an accountant independently sends another incomplete version of the same business totals.
For example, you might maintain sales records while a supporting bookkeeper records expenses. Someone must reconcile the whole record before the agreed agent submits the update. Access to software is not a substitute for agreeing that responsibility.
Questions to settle in writing
Identify who maintains records, who sends updates, who deals with corrections, who gathers other personal income and who prepares the annual return. Confirm how records and submission evidence will pass between the people involved.
When joining TaxSimba, disclose any existing accountant or bookkeeper and their current role. TaxSimba can then confirm the authorisation and work required for your agreed service. You should retain your own Government Gateway credentials; authorised agent access should not depend on giving another person your password or security codes.
Name the person who closes the annual return
Illustrative preparation example.
A bookkeeper has supporting-agent access and an accountant handles the annual position. Record who supplies missing information and who obtains final approval. Keep that agreement beside the permissions so a completed update is not mistaken for annual-return responsibility.
Check: Who is the main agent responsible for the final return, and what remains with the supporting agent?
| Check | Practical action |
|---|---|
| Main or supporting agent access? | Confirm the HMRC role and its permitted tasks. |
| Who sends the combined business update? | Avoid independent incomplete submissions by people working on different parts of the same records. |
| Who owns annual-return completion? | Name the main agent or responsible filer and confirm the service includes that work. |
Can a supporting agent submit the annual MTD return?
Not in the main-agent role required for that work. Confirm the appropriate authorisation and annual-return arrangement.
Does software access prove a task is included in the fee?
No. Check the engagement as well as technical permissions. An authorised person may still have a limited agreed scope.
Download a checklist for this guide
- List all advisers and current authorisations.
- Identify the main agent.
- Allocate record, update and correction responsibilities.
- Confirm annual-return work and handover dates.
- Keep submission evidence accessible without sharing passwords.