Mandatory Tax Adviser Registration

MTAR10100 - Scope and requirement to register: who must register as a tax adviser

Overview

All tax advisers who interact with HMRC on behalf of their clients must register with HMRC, unless a specific exception applies. For a list of exceptions, see MTAR10300.

The person or organisation that must register is the legal entity providing the service. Where the business is a sole trader, the legal entity will be an individual.

Registration is required solely in circumstances where a business:

• interacts with HMRC in relation to another person’s tax affairs
• is paid for providing that service

The following sub-sections cover what these criteria mean in more detail.

No registration requirement arises where either of these criteria do not apply, or where the business solely provides services that have been exempted from the registration requirement.

Definition of a tax adviser

For the purposes of mandatory registration, a tax adviser is defined in Section 224 of the Finance Act 2026 as an organisation or individual which, in the course of a business, assists other persons (‘clients’) with their tax affairs.

There is some overlap between this definition and the definition of a tax adviser used for the purposes of sanctionable conduct (see CH176160). However, the scope of the two measures is different, and tax advisers must consider their obligation to register separately from HMRC’s powers to address sanctionable conduct.

Assistance with a client’s tax affairs includes, but is not limited to:

• advising a client in relation to tax
• acting, or purporting to act, as agent on behalf of a client in relation to tax
• assisting with the preparation of, or providing input into, any document that HMRC is likely to rely on in determining a person’s tax position

The assistance provided must involve interaction with HMRC and be given in the course of a business for registration to be mandatory. HMRC will treat an activity as being carried out in the course of a business where it is:

• connected to a commercial or professional activity
• provided in exchange for payment, including benefits in kind
• not purely private, personal, or voluntary in nature

Free advice or work undertaken voluntarily and without payment or receiving any benefits in kind (for example, pro bono work or assisting friends and family) are not, by themselves, treated as being provided in the course of a business. However, simply providing unpaid or voluntary work as part of a business's services does not remove the requirement to register. Businesses providing a mixture of in-scope and out-of-scope or exempted services will still need to register.

When a business is determining if it needs to register, it should consider all the activities it undertakes, rather than just the primary services it provides. A business may be required to register even if it does not view itself as a tax adviser or as providing tax advice.

Individuals that are employed by the tax adviser business will not need to register, as registration is only required by the legal entity providing the services. However, HMRC will apply checks on some individuals who work within the business – these are referred to as ‘relevant individuals’. See MTAR20400 for more information about relevant individuals.

If an individual or organisation works for the business through a subcontracting arrangement, they may themselves be a tax adviser for the purposes of the registration regime, if they meet the registration requirement.

A tax adviser can be based in the UK or overseas and can operate through different business structures, including as a sole trader.

Interaction with HMRC

An individual or organisation interacts with HMRC where they do, or attempt to do, any of the following on behalf of another person in relation to tax:

• contact HMRC by telephone, post or email
• send a message to HMRC through the GOV.UK website or HMRC app
• file a return, claim, notice, disclosure or other document with HMRC, whether electronically or in paper form
• make payments to HMRC
• communicate with HMRC in any other way in connection with a person’s tax affairs

Interaction applies regardless of whether the interaction is routine, one-off, or undertaken as part of a wider professional service that is not related to tax advice.

If a tax adviser does not interact with HMRC in any way, they will not be required to register.

Examples of businesses that may be required to register

The following list shows the types of people or organisations who are likely to meet the definition of a tax adviser because of the services they provide and that, as a result, would need to register with HMRC. It is not exhaustive.

Whether a business is required to register with HMRC will depend on the business’s individual circumstances.

Examples of services include:

• a sole accounting practitioner who provides tax advice or other tax services to clients in the course of their business, and interacts with HMRC on behalf of their clients as part of providing those services
• an accountancy firm providing tax advice, tax compliance services, or acting as agent for clients, and interacts with HMRC on behalf of their clients as part of providing those services
• an agent who submits simple repayment claims on behalf of their clients
• a financial adviser or wealth manager who provides tax advice and interacts with HMRC on behalf of clients as part of a wider professional service offering
• a multi‑disciplinary professional services firm (for example, an insurance or legal firm with a tax advisory function) where tax advice services are provided to clients in the course of business, and the firm interacts with HMRC on behalf of their clients as part of providing those services
• an in-house tax professional or team which prepares or files tax returns for other entities in a corporate group

Detailed example 1: conveyancers and conveyancing-related activities

Conveyancers and solicitors’ firms that undertake conveyancing activities in the course of their business may be required to register as tax advisers with HMRC where they interact with HMRC as part of their conveyancing services.

Whether a conveyancer is required to register depends on the activities undertaken (and whether they interact with HMRC during the course of these activities) rather than the professional title of the individual or organisation.

As a result, conveyancers and other businesses may still be required to register even if they don’t see themselves as a tax adviser or interacting with HMRC does not form a significant part of their business.

Conveyancing activities that are in scope

A conveyancer is likely to be acting as a tax adviser and required to register if, in the course of a business, they:

• submit Stamp Duty Land Tax (SDLT) returns to HMRC on behalf of clients
• interact with HMRC about a client’s SDLT liabilities
• make payments of SDLT or any other taxes arising from property transactions on behalf of clients
• otherwise interact with HMRC on behalf of clients in relation to SDLT or any other taxes arising from property transactions

Submitting an SDLT return on behalf of a client is assisting with a document that HMRC is likely to rely on to determine a person’s tax position and therefore constitutes interaction with HMRC in relation to tax.

If filing and payment of SDLT are split (for example where filing is outsourced), there will be a registration requirement for both businesses. The separation of the SDLT payment from the filing activity does not remove the requirement to register.

Conveyancing activities that are not in scope

There is no requirement to register where conveyancers do not interact with HMRC directly on behalf of their clients.

This includes:

• providing advice (for example, explaining the tax consequences of a property transaction to a client) without interacting with HMRC on the client’s behalf
• providing general or factual information about SDLT rates, reliefs or deadlines
• undertaking conveyancing work where all tax returns and payments are completed directly by the client or another registered tax adviser

Providing general information or explanation alone, without acting for the client in interactions with HMRC, does not of itself constitute interaction with HMRC. However, if a firm also undertakes an activity that is in scope of the requirement, even if it is just for a small number of clients, they will need to register.

Detailed example 2: payroll organisations

Payroll organisations may be required to register as a tax adviser if they interact with HMRC in relation to other people’s tax affairs by way of business, even if they don’t call themselves a tax adviser.

Payroll activities that are in scope

For the purposes of mandatory registration, businesses are treated as ‘payroll-only’ where they solely interact with HMRC in relation to PAYE by undertaking one or more of the following activities:

• submitting information about tax and NIC deductions through Real Time Information (RTI) returns, including Full Payment Submissions (FPS) and Employer Payment Summaries (EPS)
• submitting year-end PAYE returns, such as P30, P60, or P11D
• submitting PAYE and/or National Insurance contribution payments to HMRC

Payroll activities that are not in scope

Certain payroll-related activities do not, on their own, involve interaction with HMRC. For example:

• payslip preparation and posting 
• payroll calculations (gross-to-net)
• HR‑type advice (sickness, maternity, holiday pay guidance)
• data entry, onboarding, internal record keeping
• handling employee payments via BACS (unless paying PAYE to HMRC as above)
• providing or running payroll software

If a business solely carries out these activities, they will not be required to register. However, if the business also carries out any of the ‘in scope’ activities in the section above, there would be a requirement to register.