What’s Changing?
As part of the UK’s “Modernising and Mandating Tax Adviser Registration” (MMTAR), from 18 May 2026, individuals or firms who are paid to interact with HMRC on behalf of clients will be required to register with HMRC using a new Agent Services Account (ASA). (gov.uk) This replaces older fragmented regimes and aims to raise standards across tax advice services.
Who Must Register & When
Phased registration windows allow different adviser groups to register depending on whether they have existing accounts:<br>
| Period | Who Must Register |
|---|---|
| 18 May – 18 Aug 2026 | New advisers; those without ASA, Self Assessment or Corporation Tax account |
| 18 Aug – 18 Nov 2026 | Advisers with Self Assessment or Corporation Tax accounts, without ASA |
| 18 Nov 2026 – 18 Feb 2027 | Adviser-only payroll service providers |
| 31 Dec 2026 – 31 Mar 2027 | Remainder of advisers not yet registered (gov.uk) |
There are exemptions, e.g. voluntary sector advice, or customs agents, detailed on GOV.UK. Overseas advisers interacting with HMRC are also caught if paid for the interaction. (gov.uk)
Why It Matters
- Public protection: Helps ensure clients receive reliable, accountable advice.<br>* Clarity for taxpayers: Easier to identify legitimate advisers.<br>* Compliance burden: Advisers need to confirm they meet identity checks, anti-money laundering body requirements if relevant, and maintain accurate registration details.<br>* Potential sanctions if unregistered advisers provide advice—clients could be misled, and adviser’s status compromised. (gov.uk)
Actionable Tips to Prepare
- Audit your status: Determine if you need to register and the phase that applies to you or your organization.<br>2. Gather required info: UTR for your firm, company registration number or VAT number if applicable, National Insurance / Date of Birth for sole traders or partners, and details of your anti-money laundering supervisor if you are regulated. (gov.uk)<br>3. Create an ASA now, ahead of your phase window.<br>4. Communicate changes to clients so they know you are compliant; those who don’t register may lose trust.<br>5. Seek advice if unsure: HMRC guidance helps clarify borderline cases, exemptions, etc.
Example Scenario
Sarah, a freelance consultant, has advised clients on their Self Assessment returns for years but never had an ASA. She must register in the first window (May-Aug 2026) along with other new or unregistered advisers. If she misses that, she may face restrictions.<br> Another firm offering only payroll services must register later, during 18 Nov 2026 – 18 Feb 2027.
Key Resources
- GOV.UK guidance on MMTAR<br>- The interactive checker tool on GOV.UK to determine who must register and when<br>- Details of exemptions and transitional rules are clearly set out on HMRC’s site.<br> By preparing ahead, tax advisers can adapt smoothly to this regulatory shift—and clients can feel more secure and protected in their engagements with advisers.