If you pay someone to deal with HMRC for you, whether that is an accountancy firm, a bookkeeper, a payroll bureau or a friend of a friend who "does the tax returns", a new law now applies to them. Since 2026, anyone who is paid to interact with HMRC about someone else's tax affairs must be registered with HMRC. For one large group of advisers, the deadline to apply falls in mid November 2026.
This is the adviser's obligation, not yours, and you cannot be fined for your adviser's paperwork. But if your adviser is not registered when they should be, HMRC can limit what they are allowed to do for you, and that tends to surface at the worst moment, just before the 31 January deadline. A short conversation now avoids that.
In a nutshell
- Paid advisers must register. If they are paid and deal with HMRC for you.
- One window closes in November. For advisers with older agent codes but no Agent Services Account.
- Many advisers are already covered. Existing account holders and unpaid helpers.
- Registration is not a quality badge. HMRC checks conditions, not competence.
- The penalties fall on the adviser. But a restricted adviser cannot act for you.
- Ask three questions. There is no public register to check.
1. What the new rule says
The requirement comes from Part 7 of the Finance Act 2026. In HMRC's words, if you interact with HMRC about someone else's tax affairs and you are paid for it, you are a tax adviser for these purposes and must register. Interaction is broad: phone calls, letters, emails, messages, and sending returns, claims or documents, including through software.
It is the business that registers, not each employee, and it applies whatever the job title: accountant, bookkeeper, tax agent, payroll provider, or a sole trader who files returns for a handful of clients. Registration is free and done online. HMRC opened it on 18 May 2026 and is bringing advisers in through a series of windows.
2. Who must register by November
The window that matters now is for advisers who have a Self Assessment or Corporation Tax agent code but no Agent Services Account. The Agent Services Account is HMRC's current online account for agents, and it is what Making Tax Digital runs on. Plenty of smaller practices, and many advisers serving the Polish community, have only the older agent codes.
HMRC's guidance gives this window as 18 August to 17 November 2026, while its news release says "until 18 November". The safe reading is that the application should be in by 17 November 2026.
Two later windows follow. Businesses that only run payroll, with no Agent Services Account, register from 18 November 2026 to 17 February 2027. A bureau that also does bookkeeping, VAT or tax returns belongs in the earlier windows, not this one. Financial services firms come last, by 31 March 2027.
3. Who does not need to do anything
Most established firms already hold an Agent Services Account. HMRC treats them as registered and will move them to its new service by 31 March 2027, without a fresh application. They may be asked to confirm they still meet the conditions.
The rules also do not apply to:
- Unpaid help from family or friends, and free or pro bono advice.
- In-house teams, including an employer running payroll for its own staff.
- Software providers, and services that only produce payslips without dealing with HMRC.
- People who must deal with HMRC by law, such as insolvency practitioners.
If you do your own tax return, none of this affects you.
4. What registration does and does not mean
To register, an adviser must meet HMRC's conditions: supervision for anti-money laundering by HMRC or a professional body, no outstanding returns or unpaid tax of their own (unless on a payment plan), no relevant unspent convictions for fraud or tax offences, not insolvent, and not banned or suspended. The people running the business must not be disqualified directors.
What registration is not is regulation. The government confirmed in the Autumn Budget 2025 that it will not regulate the tax advice market in this parliament. HMRC does not test qualifications or the quality of advice. A registered adviser is one who meets the conditions above, which is useful to know, but it is not a badge of competence. Membership of a professional body and good references still matter.
5. What happens if an adviser does not register
HMRC says it may limit an adviser's ability to act on behalf of clients if they fail to register when required, and that advisers who carry on could face enforcement action, including penalties.
The penalties are specific, and they fall on the adviser. After HMRC has notified the adviser and given 30 days for representations, each prohibited interaction with HMRC can cost £5,000, rising to £10,000 for repeat cases. An adviser who is suspended for more than 30 days must tell their clients, or face a further £5,000 penalty for each client not told. None of this is an automatic fine for missing the date, and none of it is charged to clients.
Two points of reassurance. An adviser who applied inside their window can keep acting while HMRC processes the application, so "applied, waiting for approval" is fine. And your own deadlines do not move: if your adviser is restricted, your return and your payments are still due on time, which is exactly why it is worth checking now rather than in January.
6. What to ask your accountant now
HMRC has not published a searchable list of registered advisers, so you cannot look yours up. You have to ask. Three questions cover it:
- "Do you have an HMRC Agent Services Account?" If yes, they are already covered.
- "If not, which registration window are you in, and have you applied?" For most, the answer should be the one ending 17 November 2026.
- "Who supervises you for anti-money laundering?" Every registered adviser must have a supervisor, either HMRC or a professional body.
A good adviser will answer all three in one sentence. Vague answers, or not knowing about the new rules at all, are worth taking seriously.
A worked example: Piotr and his bookkeeper
Piotr is a self-employed decorator under CIS. For years a bookkeeper has done his Self Assessment for £150 a year, filing under an old agent code. She has never set up an Agent Services Account, and she has not heard of the new registration.
If she does not apply by 17 November 2026, HMRC can restrict her from acting for her clients. Piotr would not be fined, but his 2025/26 return, and the CIS refund he expects from it, would still be due by 31 January 2027, and he could find himself without anyone able to file it in late January.
When Piotr asks the three questions in October, she has time to apply, with free registration and an AML supervisor in place, and nothing changes for him. If she decides to stop instead, he has months, not days, to move to another adviser.
Things to watch out for
- You cannot be fined for your adviser's registration. But your deadlines stay yours.
- No register to search. Ask your adviser directly.
- Agent Services Account holders are already covered. No new application needed.
- "Applied" is enough for now. Advisers can keep working while HMRC decides.
- Registered does not mean qualified. It means the HMRC conditions are met.
- Payroll-only bureaus register later. Mixed-service firms do not get the later date.
How Ollen Services Can Help
If you are not sure where your current adviser stands, we are happy to explain the rules in plain language and help you work out what to ask.
If your adviser is stopping, or you would rather move before the January rush, we can take over your Self Assessment, CIS, payroll or company accounts and set up the agent authorisations properly. We work in English and Polish.
Call us on 07513 491 259 or email hello@ollenservices.co.uk. Ask the three questions this week, while there is still plenty of time.