Phase two of tax adviser registration requirement now open

The second phase of mandatory tax adviser registration has now opened, with those eligible having until November to do so.

What is the Modernising and Mandating Tax Adviser Registration?

Modernising and Mandating Tax Adviser Registration (MMTAR) is a single, streamlined digital registration system that is replacing a range of previous processes, making it easier for tax advisers to interact with HMRC.

Rolling out in stages between 18^th May 2026 and 31^st March 2027, these new rules are to create better standards within the tax advice market, as well as protect taxpayers.

Phase Two of Mandatory Tax Adviser Registration

The first phase ended on the 18^th of August 2026 and applied to new tax advisers and unregistered tax advisers who interact with HMRC on behalf of new clients, but do not have an Agent Services Account (ASA), Self-Assessment account or Corporation account.

The second phase runs from the 18^th of August to the 18^th of November 2026.

This will apply to existing tax advisers and agents who already have an active Self-Assessment or Corporation Tax account with HMRC, but do not have an ASA.

You can check whether you need to register with HMRC through GOV.UK.

To find out more about contracting, please contact Jaime on 01442 795 100 or email jaime.thorpe@dolanaccountancy.com.