HMRC have now opened the second window for mandatory tax adviser registration. Advisers who have a Self Assessment or Corporation Tax account but do not have an Agent Services Account (ASA) are now eligible for registration.
All tax advisers who interact with HMRC on behalf of their clients are required to register with HMRC, unless an exception applies.
- Anyone who is paid to interact with HMRC on behalf of clients is generally considered a tax adviser.
The New registration process is aimed at raising standards in the industry and protecting taxpayers from non-compliant advisers.
The timeline for registering is as follows:
- 18 May to 18 August 2026.
- New advisers or advisers who did not already have an Agent Services Account (ASA), Self Assessment online services account or Corporation Tax online services account.
- 18 August to 18 November 2026.
- Advisers without an ASA but with a Self Assessment or Corporation Tax online services account.
- 18 November 2026 to 18 February 2027.
- Advisers who solely provide payroll services.
- 31 December 2026 to 31 March 2027.
- Financial services organisations. A full definition of this group has already been published.
Advisers that already have an ASA do not need to register again. HMRC will contact them directly via their account if any additional information is required to move them to the new system by 31 March 2027. They do not need to take any action yet.
Registration is now open for the 'second phase '; advisers without an ASA but with an HMRC Self Assessment account or Corporation Tax account must register by 18 November 2026.
- Advisers who solely provide payroll services are not required to register before 18 November 2026.
HMRC have an online tool to assist advisers with checking if and when they need to register. HMRC are encouraging advisers to use this tool and, if required, submit their registration as soon as possible.
- Registering on time will allow advisers to continue supporting clients without disruption.
- If a registration window is missed, registration should be completed as soon as possible.
- HMRC may restrict an adviser's use of their HMRC accounts if registration is late. Advisers who continue to operate without completing the registration requirement could also face enforcement action, including financial penalties.
HMRC have completed the first phase of the process and states that over 4,000 applications were submitted, with over 2,000 accounts being created. Phase one targeted the smallest agent audience group.
Useful guides on this topic
Mandatory tax adviser registration with HMRC
From May 2026, all tax advisers who interact with HMRC on behalf of clients will be required to register with them. Who will be required to register? What conditions must be met? What are the consequences of non-compliance with 'mandatory tax adviser registration'?
HMRC's Customer Charter
This is a freeview 'At a glance' guide to HMRC's Customer Charter. HMRC's Charter sets out what taxpayers can expect from HMRC and what HMRC expect from taxpayers. The latest version was issued in November 2020.
Professional Conduct in Relation to Taxation
The Professional Conduct in Relation to Taxation (PCRT) sets out the ethical and professional standards expected of members of the seven authoring professional bodies when advising on UK tax matters.
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