Mandatory Tax Adviser Registration

What does mandatory tax adviser registration mean?

Beginning in May 2026, registration is required for any ‘tax adviser’ who interacts with HMRC in relation to the tax affairs of their clients, irrespective of where the adviser or the client is in the world or where the services are provided from. 

Who needs to register?

Registration is required at firm level. However, certain registration conditions apply to individual staff members within the firm and individual officers of the firm (including partners, directors, and LLP members). If a tax adviser operates a sole trade, they must individually register in their own name.

There are limited exceptions to the requirement to register. For example, HMRC has already confirmed that those who provide pro-bono tax advice and ‘in-house’ tax advice in their own or their employer’s business are not within the scope of the regime.

The legislation also sets out a limited list of exemptions from registration which includes, inter alia, providers of payroll, tax, or accounting software who interact with HMRC in that capacity, if the HMRC interaction is in relation to an appeal to a court or tribunal, or where the adviser interacts in response to a request by HMRC.

When do advisers need to register?

HMRC has now published the official timetable for MTAR. Any tax adviser without an Agent Services Account (ASA) needs to register in tranche one, which begins from 18 May 2026, unless one of the following conditions is met:

• They have an existing Self-Assessment or Corporation Tax account (but no ASA) with HMRC: this cohort needs to register from 18 August 2026, or 
• They provide third-party payroll services on behalf of clients and do not interact with HMRC in any other way: registration for this cohort is required from 18 November 2026. 

However, as registration officially opens from 18 May 2026, those tax advisers in tranches two and three can choose to register earlier.

Tax advisers based overseas are not exempt from MTAR where they are in scope. The timetable for them to register is still not known, however HMRC has acknowledged that these advisers are likely to need longer to comply. 

Irrespective of which tranche an adviser falls into, they have three months from the date that they need to register to do so. During that time they can continue to interact with HMRC on behalf of clients, and whilst HMRC processes and considers their application.

Note that those who already have an ASA are not exempt from MTAR. Instead, there will be a lighter touch ‘transition’ which will involve moving their existing account across to the new registration system. Initial information and guidance published by HMRC indicates that HMRC will contact them via their ASA when HMRC requires further information that the tax adviser meets the MTAR registration conditions. Details are awaited on what this precisely means and its timeline.

It is also understood that those in the financial services sector and their representatives are concerned that the legislation risks bringing some activities into scope as an unintended consequence.

HMRC has therefore stated that it will work with the sector via representative bodies to ensure that the legislation is applied only where intended, including through legislative change where needed, and that the requirements are proportionate and workable.

As a result, the Government has agreed that the registration of businesses in the financial services sector will be deferred until 31 March 2027 to allow time to get this right. 

How will advisers register?

HMRC has been allocated £36 million and has been developing a new dedicated online registration system which remains in development and is not yet available. Initial registration and maintenance of a tax adviser’s registration will be free and not subject to a charge.

From recent discussions with HMRC about the new system, it seems that this will involve the existing agent identifying who their relevant individuals are, which will then require those individuals to provide permission for HMRC to share their personal data with their firm if this is related to the registration conditions. The agent will then need to confirm that their firm meets the registration conditions or explain if they do not.

What information needs to be provided when registering?

The exact registration requirements are awaited from HMRC. However, we do know that applications for registration will need to include:

• The name and address of the firm,
• The name of each ‘relevant individual’ in the firm (essentially, those individuals with responsibility for the tax work undertaken by the firm.  However, for some firms the definition may be wider than this as there are minimum numbers of ‘relevant individuals’ who must be named),
• A statement that each of the three registration conditions are met (see later), or if these are not, there must be an explanation why, and
• Any other information as HMRC may specify in a notice (we are not yet aware what this made be as no such notice has yet been published). This was another aspect challenged by us in our consultation submission.

Essentially, the number of relevant individuals to be named depends on how many ‘officers’ (company directors, partners in partnerships, and members of LLPs etc.) a firm has.  Notably, the legislation does not cap the number of relevant individuals at five and sets out different requirements for firms with five or fewer officers and those with six or more. Detailed examples of this particular aspect will therefore need to be included in the legislation’s accompanying guidance.

What are the three registration conditions?

The three conditions are that:

1. The tax adviser and each of the relevant individuals:

• must not have any outstanding tax returns or payments (unless a time to pay arrangement has been agreed and has not been broken),
• is not subject to a decision by HMRC to refuse to deal with them,
• is not subject to a relevant anti-avoidance measure,
• has not, in the last 12 months, had a relevant anti-avoidance penalty imposed on them,
• is not subject to a relevant suspension or ineligibility order,
• is not disqualified as a director in the UK, or overseas,
• does not have an insolvency practitioner acting in relation to them, and
• does not have an unspent conviction for a relevant offence, and

2. The tax adviser is registered for Anti-Money Laundering supervision (or meets such conditions about applying to register for supervision as may be specified in a HMRC notice, with no such notice yet been published), and

3. The required number of relevant individuals has been identified .

What happens after a registration application is made?

HMRC will consider the tax adviser’s registration application and will then decide whether or not to approve it at which point the tax adviser will be notified of their decision. If rejected, this can be appealed to an independent tribunal, after a formal internal review has been completed.

If the conditions for registration are met, HMRC must approve the registration. If they are not met solely because the firm or a relevant individual has an outstanding tax return or payment, HMRC can still approve the application if they consider it to be appropriate. These decisions will be based on pre-determined thresholds and circumstances, precise details of which are awaited.

At present we are also not aware of the expected timescale for HMRC to respond to registration applications, despite setting out the importance of this in our consultation submission.

The registration requirement provides HMRC with a range of monitoring and enforcement powers, and sanctions and penalties which can be imposed for non-compliance. The legislation also contains a range of safeguards, including appeal rights.

HMRC will be able to suspend a tax adviser's registration in certain circumstances, including if their behaviour does not meet ‘expected standards’ (more detail on this is also awaited which we also highlighted as an area of concern in our consultation submission).

What should tax adviser’s do now?

Preparations should begin now. Tax adviser firms should act as soon as possible to:

• Familiarise themselves with the legislation and monitor and assess HMRC guidance and information as and when it is published. This may necessitate appointing a specific team of individuals within the firm who will be responsible for implementing the legislation and ensuring it is complied with both at the time of registration and in the future,
• Identify who their relevant individuals are and how many the rules require them to include in their application,
• Determine their registration timeline,
• Audit, check, and document whether or not the firm and all relevant individuals meets the registration conditions and take remedial action where necessary, and
• Ensure that the risk of suspension/prohibition, including the impact of this on their clients and how this would be managed is built into the firm’s contingency planning.