Individuals can sign up now, either to test MTD income tax for 2025/26 (subject to meeting eligibility requirements) or early for 2026/27 submissions. It is also possible for an agent to do this on their client’s behalf.  

It is important that agents follow HMRC’s guidance if they are to successfully sign up clients for MTD income tax. ICAEW is reminding agents that the ASA is key to this process and to ensure that they: 

• have set up an ASA. The ASA allows agents to access a range of HMRC’s digital services, including VAT. It is different from the online services for agents account (OSA). HMRC has published guidance on how to set up and use an ASA; and
• are authorised by their client for self assessment in their ASA. Existing client authorisations for self assessment are recognised for MTD income tax. However, where the authorisation is in the OSA only, the agent will need to add the authorisation to their ASA. Where the agent is not authorised for self assessment by their client, they should follow the steps in the ASA to ask their client to authorise them.  

It should be noted that while an agent may have several different OSA government gateway logins, they will only have a single ASA login. A list of government gateway IDs where authorisations are linked can be accessed in the ASA. The agent should check this to determine what action, if any, they need to take with regard to their client.   

Once an authorisation has been added to the ASA, the agent’s OSA will be linked with their ASA. This means that: 

• new clients will be added to both accounts; and 
• where the agent ceases to act for a client, they will need to delete the authorisation from both accounts.  

HMRC says that adding an authorisation to the ASA will not remove access in the OSA. The agent will still be able to use their OSA for self assessment and for clients who don’t need to use MTD income tax.  

Further information 

• HMRC has a YouTube video explaining how to create an ASA and how to add existing client authorisations to the ASA.
• HMRC hosts a webinar on how to sign clients up for MTD income tax. Agents can register to join the next live webinar or to watch a recording of the webinar.