Despite concerns over implementation costs, compliance burden and effectiveness raised by bodies such as the ICAEW, HMRC's new registration regime for tax advisers began on 18 May 2026. The stated objective of the regime is that all advisers who "interact" with HMRC as part of a service for others must register as a tax adviser and meet minimum standards. HMRC aims to exclude advisers that are not registered or fail to meet those standards. This initiative arises against a backdrop in which tax advisers have not been independently regulated to date and a persistent loss of tax revenue due to the number of tax avoidance schemes, usually devised and implemented by unregulated and unregistered advisers and that have not been prevented by other avoidance measures that have previously been brought in.
The registration requirement will be phased in, with the first group of businesses having until 18 August 2026 to register with HMRC. HMRC say that the new regime will replace the current patchwork of registration routes with a single, streamlined digital system. HMRC has recently published its mandatory tax adviser registration manual, which provides detailed guidance on some aspects of the rules.
Scope: a broad definition of “tax adviser”
The definition of a “tax adviser” is very broad (Section 224, Finance Act 2026). In essence, any individual or organisation that, in the course of business, assists another person with their tax affairs and interacts with HMRC will fall within scope. The term "interaction" is also very broad and includes filing tax documents and any communication with HMRC. As a result, the regime extends well beyond traditional tax advisory practices. Not only will it capture accountancy and audit firms and payroll providers, it is likely to extend to other professional services organisations including lawyers, letting agents and property managers whose work involves engagement with HMRC. It also applies to overseas advisers acting for UK taxpayers.
There are various exclusions from the regime, including: in-house lawyers and advisors dealing only with tax affairs for their company; services provided on a non-commercial or charitable basis; certain statutory roles (e.g. insolvency practitioners); and limited categories of interaction, such as court proceedings or certain customs and VAT matters. However, the boundaries of these exclusions are not always clear. Further guidance from HMRC is anticipated as the regime beds in.
In practice, many accountancy firms will not be adversely impacted by this new regime, however small businesses and other professional services firms may be. They will need to reassess activities that may previously have been seen as incidental (for example, submitting returns or liaising with HMRC as part of wider engagements), as these activities are likely to bring them within scope and trigger the registration requirement. Many firms are likely to need advice on this from their own accountants and tax advisers in these circumstances.
Key requirement: registration before interacting
A central feature of the regime is the prohibition on unregistered advisers interacting with HMRC on behalf of clients. In practical terms, once the relevant commencement date has passed for a particular category of adviser (see further below), HMRC can refuse to engage with unregistered agents with penalties being potentially issued for continued non-compliance. Once registered, HMRC will also monitor ongoing compliance with the registration requirements and may suspend an adviser's registration in the event of non-compliance or where an adviser's behaviour does not meet expected standards.
The registration requirement is being introduced on a staged basis between 18 May 2026 and 31 March 2027. Businesses have three months from their start date to register with HMRC. The start date is 18 May 2026 unless a later start date applies or the business has an Agent Services Account (ASA). The later start dates are:
- 18 August 2026: for businesses that have a self-assessment or corporation tax account but which do not have an agent services account (ASA);
- 18 November 2026: businesses providing payroll-only services on behalf of clients; and
- 31 December 2026: financial services organisations.
A business that already has an ASA does not need to take any action yet. HMRC will contact the business through their ASA between 31 December 2026 and 31 March 2027 if more information is required, for example, about the relevant individuals of the business. Most firms will have a three-month window to complete registration and may continue interacting with HMRC while their application is being processed.
Registration process and conditions
Registration will be completed through HMRC’s portal, which has been created at an alleged investment of c£36m. Individuals and firms seeking registration and maintaining that registration must meet HMRC's conditions, which include: demonstrating appropriate supervision for anti-money laundering purposes; complying with HMRC's standards for tax agents; and provision of information about the firm and key individuals involved in delivering tax-related services.
Looking ahead
The introduction of a mandatory registration regime for tax advisers represents a significant step in HMRC’s efforts to regulate the tax advice market more closely. The fact that it is HMRC that is undertaking this regulation, rather than an independent regulator, has attracted significant debate and remains contentious. The ICAEW has declared this a potential existential threat. Whether HMRC is able to allay those fears in the implementation and running of the registration programme will only be judged once this new system has been in operation for a period of time.
In addition, while there is industry-wide consensus to improve the quality and standards of tax advice and to stamp out the promotion of tax avoidance schemes that have no reasonable prospect of success, there remain significant concerns including over whether the regime will achieve these objectives. The designers and promoters of such tax schemes are unlikely to register or interact with HMRC and therefore they will fall outside the scope of the registration.
