Yes, if they deal with HMRC for you. Part 7 of the Finance Act 2026 stops a tax adviser interacting with HMRC about a client’s tax affairs unless the adviser is registered with HMRC or an exception applies. Interacting is drawn widely: a telephone call, a letter, an email, a message through a portal, and the filing of any return, claim, notice or other document. An adviser who submits your Additional Information Form or your amended return is inside the rule, and so is one who only picks up the phone about your claim.
When it applies
The requirement arrives cohort by cohort rather than all at once. Regulations made in July 2026 set four appointed days, and the prohibition does nothing to an adviser until theirs arrives.
- 18 August 2026 — the first tranche, which is every adviser not in a later one. Firms holding an Agent Services Account are all in it, because each later tranche is defined by not holding one immediately before that date.
- 18 November 2026 — the second tranche.
- 18 February 2027 — the third.
- 1 April 2027 — the fourth, which is where HMRC placed financial services organisations.
Registration opens earlier for each group, in a window running roughly three months ahead of its appointed day. HMRC’s stated practice is that an adviser who applies within their own window may carry on acting while the application is considered.
Established firms do not apply at all
A firm holding an Agent Services Account immediately before 18 August 2026 is treated by the regulations as having applied, been approved and been notified, with registration taking effect from that date. No form, no fee, nothing to renew. HMRC expects to contact those firms in early 2027 to collect the names of their relevant individuals and evidence of anti-money-laundering supervision.
So a long-standing adviser who tells you they did not have to do anything may be describing the rule correctly rather than dodging the question.
You cannot look it up
Part 7 creates no register. There is no list and no lookup: HMRC notifies the adviser, and that is the whole of it. The publication powers in the Act point the other way. Chapter 1 lets HMRC publish penalties and ineligibility orders; Chapter 2 lets it publish refusals to deal with an adviser and suspensions of online access. The Act can name the delinquent and has no power to name the compliant.
What is left is asking — and asking about the right company. Registration sits with each legal entity separately, so a registered company elsewhere in an adviser’s group says nothing about the one that signs your engagement letter.
Registration is not a quality mark
HMRC says so itself. Its fact sheet on the regime states that registration “is not a form of regulation and does not reflect your competency or authorise you to advise on tax matters”. The conditions are about conduct and standing rather than skill: no overdue tax or outstanding returns, no disqualified directors, no unspent conviction for a relevant offence, no current suspension, and anti-money-laundering supervision in place. Nothing in the process tests whether an adviser understands R&D. “Tax adviser” remains an unprotected title, and no exam stands behind it.
The adviser who never contacts HMRC
Some R&D firms write the report, hand it over and leave your accountant to file. Such an adviser never interacts with HMRC, so this part of the Finance Act 2026 does not reach them at all.
The older requirement still does. Under the Money Laundering Regulations 2017 a tax adviser is a firm or sole practitioner giving material aid, assistance or advice on another person’s tax affairs, whether directly or through a third party, with no contact with HMRC needed. Supervision has been compulsory since 2017, and trading without it is a criminal offence carrying up to two years’ imprisonment. Two registers, different nets, and the older one bites harder.
What you can actually check
The verifiable signals are the ones that were there before any of this. ICAEW publishes a register of chartered accountants and CIOT a directory of Chartered Tax Advisers, both searchable against the named person who will prepare your claim. AML supervision can be put as a direct question, and a supervised firm answers it in a sentence. How to choose an R&D tax adviser sets out the rest of what is worth checking before you appoint anyone.
For our own answers: LimestoneGrey holds an Agent Services Account, so it is registered under the transitional rule with effect from 18 August 2026, and ICAEW supervises the firm for anti-money-laundering purposes. What we do and how we work covers the engagement itself, and regulation and professional standards sets out each layer and the complaints route behind it.
Sources
- Finance Act 2026, section 223 — “A tax adviser may not interact with HMRC in relation to the tax affairs of a client” unless registered or within a Schedule 20 exception, and the definition of interacting, which includes telephone, post, email, portal messages and the filing of a return, claim, notice or other document.
- Finance Act 2026, section 224 — who counts as a tax adviser, including a person who “provides assistance with any document that is likely to be relied on by HMRC to determine the other person’s tax position”.
- Finance Act 2026, section 227 — the registration conditions, including anti-money-laundering supervision and the conduct and standing tests.
- Finance Act 2026, section 246 — the Chapter 1 publication power, which reaches penalties and ineligibility orders.
- SI 2026/807, the commencement regulations for Part 7 of the Finance Act 2026 — regulation 4, setting the appointed days of 18 August 2026, 18 November 2026, 18 February 2027 and 1 April 2027; and regulation 5, deeming advisers who hold an Agent Services Account immediately before 18 August 2026 to have applied, been approved and been notified.
- Check if and when you need to register as a tax adviser with HMRC — the registration windows, HMRC’s statement that a firm with an agent services account “will not need to register again”, and its practice of allowing advisers to continue acting while an application made in their window is considered.
- Mandatory tax adviser registration communications resources: fact sheet — HMRC, 14 May 2026: registration is free and “is not a form of regulation and does not reflect your competency or authorise you to advise on tax matters”.
- Anti-money laundering registration — supervision as a legal requirement for tax advisers: “You’re breaking the law if you carry on a business activity covered by the regulations but do not register with a supervisory authority.”
- The Money Laundering Regulations 2017, regulation 86 — trading without required registration as a criminal offence, with imprisonment of up to two years on conviction on indictment.
This page describes the rules as they stood at the review date above, as general information rather than advice on your circumstances. For how that distinction works, see our terms; for an answer on your own facts, talk to us.