HMRC’s mandatory tax adviser registration scheme is moving into its next stage, with an important deadline approaching on 18 November 2026. Accountancy firms that use Self Assessment or Corporation Tax agent accounts but do not have an Agent Services Account (ASA) must register within the current window.
The new rules aim to raise standards in the tax advice market and protect people who rely on professional support. Firms that miss the requirement could face restrictions on acting for clients and enforcement action. Trustees and businesses should also understand how the changes may affect their tax arrangements.
Who Needs to Register with HMRC?
The new system applies to businesses that get paid to deal with HMRC on behalf of other people. This can include preparing and submitting tax returns, sending claims, and communicating with HMRC about a client’s tax affairs.
The requirement applies even if a business does not describe itself as a tax advisory firm. The key question is whether it is paid to interact with HMRC on behalf of clients.
The current registration window opened on 18 August and closes on 18 November 2026. It covers advisers with Self Assessment or Corporation Tax agent accounts who do not already have an ASA.
Firms that already hold an ASA do not need to register again. HMRC plans to contact them in early 2027 if it needs further information. The next phase, opening on 18 November, covers businesses that provide only professional payroll services.
What Trustees and Accountancy Firms Should Know
Trustees should check whether their work falls within the new rules. Acting as a trustee does not automatically mean a person must register. However, a firm that provides paid tax services and deals with HMRC on behalf of clients may need to register.
This distinction matters for firms that handle trust or estate tax returns. They should review the work they perform and confirm whether the registration rules apply to their business.
Accountancy firms must also identify the relevant individuals HMRC needs to check. These may include people who make key decisions about how the firm’s tax advice services are managed or organised.
The rules depend on the firm’s structure. Smaller businesses may need to identify all their officers, while larger firms must assess who has significant management or oversight responsibilities. The aim is to check the people who have a real role in running the firm’s tax advice work.
AML Checks and Tax Compliance Conditions
Before applying, firms must meet HMRC’s registration conditions. One key requirement is approved anti-money laundering (AML) supervision. A pending application for AML supervision is not enough.
Businesses should also review their tax affairs and those of the relevant individuals. Outstanding tax returns, unpaid tax, and certain tax avoidance sanctions may affect eligibility. HMRC’s rules allow for some circumstances, such as unpaid tax covered by an agreed Time to Pay arrangement.
Firms should not leave these checks until the final days of their registration window. They may need time to confirm their AML status, identify the right individuals, and prepare the information required for an application.
What Happens If a Firm Misses the Deadline?
HMRC says advisers should register as soon as possible if they miss their window or are new to the market. Firms that submit an application can continue to interact with HMRC while it is being processed.
However, advisers who fail to register when required may face limits on their ability to act for clients. Continued non-compliance can also lead to enforcement action, including financial penalties.
Business owners and trustees should therefore ask their advisers whether the new requirements apply to them and whether any registration steps remain outstanding.
What Should Firms Do Now?
Accountancy firms should check their registration category, confirm that their AML supervision is approved, identify relevant individuals, and review their tax compliance before applying. They should use HMRC’s official guidance and registration checker to confirm the steps that apply to their business.
Lanop supports businesses with tax compliance, accounting, and related advisory needs. Its team can help clients understand their tax obligations and prepare for changes that may affect their business. Seeking advice early can help firms identify issues and take the right steps before they disrupt their work.
