HMRC expands MTD for Income Tax testing and allows taxpayers to authorise multiple agents

As we enter the final year of testing before the first group of sole traders and landlords are legally required to submit quarterly updates under Making Tax Digital (MTD) for Income Tax, HMRC has expanded the number of taxpayers who can test as well as launching its service to authorise multiple agents. 

We have also received several queries in recent weeks from our members about authorising clients for the Agent Services Account (ASA) more and have been supporting on queries with registering clients for MTD on the HMRC website. 

Get involved with testing 

HMRC would like to encourage firms to ideally sign up between 5% and 10% of the clients who will ultimately be required to submit quarterly updates for the testing phase. On launching the public beta phase of testing, the number of taxpayers who can volunteer to take part has also increased. It’s important to remember that you’ll also need to use compatible software and it’s necessary for the business to have a 31 March or 5 April accounting year end. 

It’s still not possible for a taxpayer to sign up if they have a payment plan with HMRC; are a partner in a partnership; claim Married Couple’s Allowance; claim Blind Person’s Allowance; are currently, or are going to be, bankrupt or insolvent; are an MP, minister of religion or Lloyds underwriter; have income from being a foster carer or being in a shared lives scheme; have income from a trust; are subject to a compliance enquiry; use ‘averaging’ for farmers, writers or artists; or are signing up on behalf of someone else (unless you’re an agent), such as an insolvency practitioner, nominee or solicitor. 

If you’re unsure whether a business is eligible, HMRC has an eligibility checker as part of the sign up process.  

Register a client for MTD for Income Tax 

HMRC has recently issued updated guidance on the authorisation of clients for MTD for Income Tax at Sign up your client for Making Tax Digital for Income Tax and Add your client authorisations for Making Tax Digital for Income Tax. 

While new clients may need a 'digital handshake' to authorise an agent, it’s possible to copy across an existing agent authority from the HMRC legacy system onto the ASA so that a main agent can act on behalf of an existing self-assessment client without further client approval being needed. This is a point which HMRC had previously not made very clear until recently, but it is unnecessary to seek further approval from those clients where a 64-8 mandate is already in place. 

This doesn’t apply to supporting agents, who’ll need to register under the new authorisation process for multiple agents (see below). 

Multiple agents can now act for a client 

When registering a client on the ASA for MTD for Income Tax, you can ask to be either a main agent or supporting agent for your clients. Each type of agent can view different parts of a client’s records and do different tasks. 

This would allow, for instance, a bookkeeper to complete and submit quarterly updates as a supporting agent and an accountant to complete the year end submission in their tax return as a main agent. More details on the difference between a main agent and supporting agent can be found on the Choose agents for Making Tax Digital for Income Tax guidance. 

Main agents can carry out most tasks that their client can, apart from setting up a Direct Debit for the client or changing how the client wants to be contacted by HMRC. Supporting agents are unable to do those tasks, nor can they view all sources of a client’s income for self-assessment, finalise a client’s overall tax position, submit a client’s tax return or view a client’s tax calculation. 

Don’t forget to sign up clients who will be mandated from April 2026 

Where a sole trader or landlord will be legally required to submit quarterly updates, you can now register for MTD even if the business won’t be taking part in the testing phase. We would encourage you to start this process now for your client base, to avoid having to do this closer to April 2026. 

Let us know your views 

We welcome your views, which help inform our work on consultations or other tax-related matters. We respondedto many tax calls for evidence and consultations, as well as producing tax policy papers and reports. We also regularly attend meetings with HMRC at which service levels, delays and other issues are discussed, and we raise problems being encountered by members. 

Please get in touch to share your insights and feedback.