Quick Answer
HMRC's mandatory tax adviser registration scheme launches 18 May 2026. The duty to register falls on accountants and tax advisers — not on you as a client. If your accountant holds a professional body designation (ACCA, ICAEW, CIOT, ATT), they are almost certainly already compliant. The risk is concentrated among unregulated advisers with no professional body membership.
What Is HMRC's Mandatory Tax Adviser Registration Scheme?
From 18 May 2026, HMRC is requiring every tax adviser and accountant who interacts with HMRC on behalf of paying clients to formally register under a new mandatory scheme. This is the first time any statutory registration requirement has applied to the UK tax advice sector as a whole. Currently, anyone can call themselves a tax adviser or accountant — the title is unprotected and there is no existing mandatory standard for working with HMRC on behalf of others.
The scheme is designed to close that gap. HMRC estimates approximately 85,000 tax agent businesses will be required to register. The government invested £36 million in the new registration infrastructure, and the primary legislation sits in Finance Bill 2025-26. The registration service is free — HMRC will not charge advisers to register or remain on the register.
The scheme covers anyone who submits returns, corresponds with HMRC, uses HMRC online services, assists with compliance checks, or prepares documents affecting a client's tax position — and is paid to do so. It also applies to overseas-based advisers acting for UK taxpayers.
HMRC Adviser Registration Launch Date
Penalty — First Breach
Tax Agent Businesses Affected
Who Has to Register — and by When?
Registration is phased across four groups, each with a three-month window from their start date:
- 18 May 2026 — New advisers, or those with no existing Agent Services Account (ASA), Self Assessment, or Corporation Tax account
- 18 August 2026 — Advisers who already hold a Self Assessment or Corporation Tax account but do not have an ASA
- 18 November 2026 — Those who only provide third-party payroll services on behalf of clients
- 31 December 2026 — Financial services organisations
Full roll-out completes by 31 March 2027. Most established accountancy practices — which will already have an Agent Services Account — fall into the August 2026 group.
Registration is at firm level, not per individual adviser. However, HMRC will run checks on "relevant individuals" within the firm — typically directors and partners — to confirm no outstanding tax obligations or compliance concerns.
What Minimum Standards Must an Adviser Meet?
HMRC's registration conditions centre on three things. First, the firm must be supervised for anti-money laundering (AML) purposes — either through a professional body or HMRC itself. Second, the firm and its relevant individuals must have no outstanding tax obligations or compliance history that disqualifies them. Third, the firm must commit to HMRC's Standards for Agents — broadly equivalent to the Professional Conduct in Relation to Taxation (PCRT) framework that ACCA, ICAEW, and CIOT members already follow.
Annual assurance submissions are required on an ongoing basis. Failure to comply triggers a suspension from acting, and ultimately prohibition — meaning HMRC will not allow the firm to represent clients at all.
Financial penalties are set at £5,000 for a first breach after a compliance notice, and £10,000 for a repeat offence within two years or for continuing to act during a suspension or prohibition period.
Why the AML condition matters
AML supervision is the central gate. Firms supervised by ACCA, ICAEW, the Law Society, CIOT, AAT, or HMRC's own MLR supervision service already satisfy this condition. The risk lies with advisers who are genuinely unsupervised — operating without any professional body and without registering directly with HMRC for AML purposes.
What This Means If Your Accountant Is ACCA, ICAEW, or CIOT Registered
If your accountancy firm holds a professional body designation — FCCA, FCA, CTA, ACA, ATT — this scheme is primarily a compliance exercise for them, not a structural change. The central registration condition (AML supervision) is already met by membership of any of these bodies. PCRT compliance, which ACCA and ICAEW members must observe, directly maps onto HMRC's Standards for Agents.
The practical steps for a firm like this are: confirm the relevant individuals have no outstanding HMRC obligations, apply for or confirm their Agent Services Account, and submit the registration assurance. For an established, well-run practice, this is a paperwork task, not a structural change to how they operate.
For agency founders working with a regulated accountant, the expected experience is: nothing changes. Your firm registers behind the scenes, and your returns, payroll, and correspondence continue as normal.
When Should You Actually Be Concerned?
The scheme exists precisely because there are tax advisers operating in the UK without professional body membership, without AML supervision, and without any formal accountability to a standards framework. HMRC's own estimate of ~85,000 affected firms is larger than the number of formally regulated practices — the gap represents advisers currently operating in an unregulated space.
The red flags to look for if you are evaluating your current accountant or switching:
- No professional body designation listed on their website (ACCA, ICAEW, CIOT, ATT, AAT)
- No AML supervision certificate or reference to their MLR supervision
- Recently established with no professional qualifications or track record
- Unusually low fees that make it difficult to understand how qualified supervision is being funded
This is also relevant for agency founders using a relatively new or informal bookkeeper or tax preparation service for parts of their HMRC interactions. If that person or firm is paid and interacts with HMRC on your behalf, they are in scope.
For context on the broader compliance obligations that flow from choosing the right accountant, see our guide on how to switch accountants in the UK.
The One Check Worth Making Right Now
If you use a regulated accountant — ACCA, ICAEW, CIOT, ATT member firm — the one check worth making is a brief confirmation: ask your accountant whether their firm has registered (or will register by their deadline) under the new HMRC mandatory tax adviser scheme.
A well-run regulated practice should answer in one sentence. If the answer is vague or the question prompts uncertainty, that is worth probing further.
No public register yet
ICAEW flagged in February 2026 that HMRC's guidance does not yet confirm a publicly searchable register of registered tax advisers — there is no equivalent of the FCA register for tax advisers at this stage. Client-side verification currently relies on asking your accountant directly. Asking for their professional body practice number (e.g., an ACCA practice registration number) is the most reliable proxy.
For agency founders thinking about the broader question of whether your current accountant genuinely understands agency finances — retainer billing, utilisation, WIP — it is worth reviewing our questions to ask before hiring an accountant for your agency. Regulatory compliance is the baseline; agency expertise is the differentiator.
While you're reviewing your financial setup, it's also worth checking whether your current salary and dividend split is optimised for 2026/27 — use our director salary calculator to model the most tax-efficient combination.
What Happens If Your Accountant Fails to Register?
If HMRC suspends or prohibits an adviser, that firm cannot interact with HMRC on any client's behalf. They cannot submit returns, respond to enquiries, access agent online services, or act in a compliance check. From a client's perspective, this means you would need to appoint a new registered adviser — potentially at short notice.
For an agency, the practical consequences could include: missed filing deadlines if a tax return or confirmation statement is due during the disruption, unresolved HMRC correspondence, and gaps in payroll submission if the adviser also runs your PAYE. The cost of switching accountants mid-year — briefing a new firm, handover of records, re-authorisation with HMRC — is non-trivial.
HMRC's stated position is that "clients have the choice of engaging the services of other registered tax advisers," which is technically accurate but underestimates the disruption of an unplanned mid-year transition.
This is also relevant if your agency uses contractors managed through umbrella companies. Some umbrella payroll providers interact directly with HMRC on behalf of contractors — a registered compliance adviser in your supply chain matters more than it might initially appear. See our guide on IR35 and contractor compliance guide for agencies for the broader supply chain compliance picture.
Frequently Asked Questions
Does HMRC mandatory tax adviser registration affect me as a business owner?
No direct obligation falls on you as a client. The duty to register sits entirely with your tax adviser or accountancy firm. However, if your adviser fails to comply by their relevant deadline, HMRC will not allow them to interact on your behalf — which could disrupt filings, correspondence, and compliance checks at short notice.
How do I know if my accountant has registered with HMRC?
There is currently no publicly searchable register — ICAEW has flagged this gap in HMRC's guidance. The most reliable approach is to ask your accountant directly. Any qualified, professionally regulated firm should be able to confirm their registration status immediately. ACCA, ICAEW, CIOT, and ATT members already satisfy the central AML supervision condition, so regulated practices are the lowest risk.
What happens if my accountant does not register by the deadline?
HMRC will block them from interacting on your behalf — they cannot submit returns, respond to correspondence, or act during compliance checks. You would need to appoint a different registered adviser, potentially at short notice and mid-year. This is why the scheme matters to clients of unregulated advisers who may not comply.
Do ACCA-registered accountants need to do anything different under this scheme?
ACCA practices already satisfy the central registration condition — AML supervision through ACCA. Their main tasks are identifying relevant individuals at the firm, confirming no outstanding tax obligations, and obtaining or confirming their Agent Services Account (ASA). These are standard compliance steps for any properly run practice, not a structural change.
Is there a list of registered tax advisers I can check?
Not yet. HMRC has not confirmed a publicly searchable register equivalent to the FCA register. Until one exists, asking your accountant for their professional body registration number — for example, an ACCA practice registration number — is the most reliable proxy for confirming they meet the scheme's standards.
How Alto Accounting Is Handling This
Alto Accounting is an ACCA registered practice. We are AML supervised through ACCA and we meet the central registration condition for the new mandatory scheme. For clients of Alto, no action is required on your part — we will register under the new scheme ahead of our relevant deadline.
If you have any questions about the registration scheme or want to confirm your current accountant's status, we are happy to help. Use our free consultation to speak with us, or explore our IR35 compliance guide if contractor status is also a concern for your agency.
For agencies looking to optimise their financial structure alongside staying on top of compliance, try our agency profitability calculator — a quick way to see whether your current margins, utilisation, and overhead ratios are in a healthy range.