Professional indemnity explained

HMRC tax adviser registration: deadlines and what it means for PI

Reviewed by the Apex broking team · Last reviewed 2026-10-31

HMRC tax adviser registration is the requirement for anyone paid to deal with HMRC on a client's tax affairs to register and meet minimum conditions. It matters because missing your window can restrict your ability to act for clients.

Part of: Professional indemnity insurance

Who has to register, and from when

The short answer: if you are paid to deal with HMRC on someone else's tax affairs, you generally have to register with HMRC as a tax adviser, unless an exception applies. Registration opened on 18 May 2026 and is being phased in by group until 31 March 2027. HMRC's policy paper (26 November 2025) explains that advisers who do not meet the minimum standards or registration conditions can be suspended from dealing with HMRC for clients.

According to HMRC's announcement of the second window, registration is free and online. Advisers who already hold an agent services account do not need to register again; HMRC says they will be moved to the new digital service by 31 March 2027. Advisers who miss their window may find their ability to act for clients restricted, and those who carry on without registering could face enforcement action, including financial penalties.

This catches more firms than traditional tax practices. Bookkeepers, payroll bureaux and some law firms deal with HMRC for clients, and HMRC's manual lists the exceptions, so check them rather than assuming you are outside the rules.

The registration windows

HMRC's manual page MTAR10800 sets out three month windows by group of adviser:

HMRC's press releases describe the closing dates as 18 August, 18 November and 18 February, so work to the earlier date to be safe. The payroll and financial services windows apply only where a business provides those services alone. A firm that also does other tax work for clients belongs in the earlier group. If you register within your window, you can keep acting for clients while HMRC processes the application.

The registration conditions

HMRC's manual page MTAR20200 lists the conditions. When applying, the business must not:

• have relevant outstanding tax returns or unpaid tax, unless covered by an agreed Time to Pay arrangement;
• be subject to an HMRC decision refusing to deal with it;
• be subject to an anti-avoidance sanction or stop notice, or any anti-avoidance penalty in the last 12 months;
• be disqualified from acting as a director;
• have relevant unspent convictions for fraud or tax offences;
• have an insolvency practitioner acting in relation to it; or
• be suspended or permanently banned from registering with HMRC.

Relevant individuals declared by the business must meet the same conditions. The business must also provide evidence of anti-money laundering supervision, and HMRC says that having merely applied for supervision is not enough. New practices should arrange AML supervision well before their window closes. AML supervision itself is set to move to the FCA from around 2028; see the FCA AML supervision reform.

Is PI insurance a condition of registration?

Not on HMRC's published conditions. Neither the policy paper nor the MTAR20200 list of registration conditions mentions professional indemnity insurance. That does not mean PI is optional in practice:

• Professional bodies set their own rules. Accountants regulated by ICAEW, for example, must meet its PII requirements; see ICAEW PI requirements.
• Members of the bodies that adopt Professional Conduct in Relation to Taxation (PCRT) work to an updated version that, according to ICAEW, applies from 1 January 2026 and adds paragraphs on dealing with third parties and disagreements with clients.
• Clients, lenders and engagement terms commonly expect advisers to hold PI, whatever the regulatory position.

Registration also creates new ways to cause client loss. If an adviser is restricted from acting and a client misses a filing or a relief deadline as a result, the client may allege negligence. A claim like that could fall under PI, subject to the policy terms. A penalty imposed on the adviser for failing to register is a different matter: fines and penalties are commonly excluded, as explained in our guide to fines under PI. For more on the PI angle, see HMRC tax adviser registration and PI insurance.

Illustrative examples

Illustrative example 1: the new practice. A newly qualified adviser sets up in June 2026 and applies for AML supervision in August. The supervisor's approval arrives after the first window closes, so the registration is late. HMRC restricts the adviser's ability to act, and a client misses an amendment deadline. The client's claim for the lost relief would usually be considered under PI, subject to the terms. See PI for new tax advisers.

Illustrative example 2: the payroll bureau. A bureau assumes it can wait for the payroll window, but it also files a few Self Assessment returns for directors. Because it does more than payroll alone, it falls into an earlier group. See also PI for payroll consultants.

Illustrative example 3: the established firm. An accountancy firm with an agent services account does not need to re-register, but still checks that every relevant individual meets the conditions before HMRC migrates the account by March 2027.

Common mistakes

• Assuming you are not a tax adviser. HMRC treats anyone paid to interact with it on another person's tax affairs as generally in scope unless an exception applies.
• Leaving AML supervision to the last minute. A pending application does not satisfy the condition.
• Picking the wrong window. The later payroll and financial services windows are only for businesses that provide those services alone.
• Reading registration as a PI requirement, or as proof PI is unnecessary. HMRC's conditions are silent on PI, but professional bodies and clients are not.
• Forgetting individuals. Declared relevant individuals must meet the same conditions as the business.

Practical steps and what to check with your broker

1. Confirm which window applies to your business and diarise the earlier possible closing date.
2. Check your AML supervision is in place and that you hold evidence of it.
3. Review each relevant individual against the conditions, including tax affairs and director disqualification.
4. Review your PI limit, retroactive date and any exclusions for regulatory or registration failures. Our guides on how much PI cover tax advisers need, PI claims examples for tax advisers and retroactive dates can help.
5. Read more in the tax advisers PI guide 2026, the accountants PI guide, bookkeepers insurance and the tax advisers risk hub.

Apex arranges professional indemnity insurance for tax advisers, accountants and bookkeepers; a broker reads every enquiry.

Sources

• HMRC policy paper: Tax advisers to register with HMRC and meet minimum standards
• HMRC: Second registration window now open for tax advisers
• HMRC manual MTAR10800: when tax advisers must register and transitional arrangements
• HMRC manual MTAR20200: standards expected of tax advisers
• ICAEW: Updated version of PCRT to apply from January 2026

Frequently asked

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority. Registered in England and Wales, company number 07014570. This page is general information, not advice on your individual circumstances, and it does not guarantee that cover will be available or on what terms.