Tax advisors should check if they need to register under new rules, following new guidance issued by the government (which has already been updated, so worth keeping an eye on).

From 18 May 2026, a new mandatory tax adviser registration requirement began to be rolled out by HMRC. Intended to “protect customers and raise standards in tax advice”, the online registration continues rolling out in stages until 31 March 2027. Registration is free, and step-by-step guidance is available on GOV.UK to help advisers understand what they need to do and when, in the form of a free q&a tool.

The tool says “If you interact with HMRC about someone else’s tax affairs and get paid for it, we consider you to be a tax adviser. This means you’ll need to register for an agent services account.” You may have to register even if you do not see yourself as a tax adviser, for example, if you submit or pay Stamp Duty Land Tax (SDLT) returns or claims on behalf of clients.

It will be introduced gradually, with different groups invited to register at different stages:

18 May to 18 August 2026

New tax advisers, or advisers interacting with HMRC without an ASA, Self Assessment or Corporation Tax account.

18 August to 18 November 2026

Advisers with a Self Assessment or Corporation Tax account, but without an ASA.

18 November 2026 to 18 February 2027

Advisers who solely provide payroll services.

31 December 2026 to 31 March 2027

Those who already have an ASA, and Financial services organisations. A full definition for this group will be published soon via secondary legislation.

Advisers will have three months from the start of their registration window to apply for an ASA. They can continue to interact with HMRC on behalf of their clients:

• during these three months
• while HMRC considers their registration.

If a tax adviser already has an ASA, they do not need to register again. HMRC will contact them through their ASA if any additional information is needed to move them to the new digital system.

HMRC said: “Further detail has been added to help businesses identify their relevant individuals, as well as examples of the types of evidence that may be required for anti-money laundering checks.”

It adds: “If your business has 6 or more officers, first identify those who actually make strategic or management decisions about your tax advice work. Do not include all officers by default. In some cases, fewer than 5 officers will meet this definition. If this happens, you must choose additional officers so that you have at least 5 in total. You can choose which officers to include. They do not have to be the most senior or responsible for day-to-day tax advice.”