Tax advisers must register with HMRC by 18 November. Check whether this applies to you

04.11.2026, 10:57 (UK time)

News

HMRC is running the second stage of mandatory registration for tax advisers. The window opened on 18 August 2026 and closes on 18 November 2026. It applies to advisers who have a Self Assessment or Corporation Tax account but no agent services account (ASA).

HMRC generally treats anyone who is paid to deal with it about someone else’s tax affairs as a tax adviser, unless an exemption applies.

Analysis

The first window closed on 18 August. According to HMRC, it received more than 4,000 applications and more than 2,000 accounts were created. Further dates:

• those who only provide payroll services: from 18 November 2026 to 18 February 2027,
• financial services organisations: from 31 December 2026 to 31 March 2027,
• anyone who already has an ASA does not register again – they will be moved to the new service by 31 March 2027.

What it means

This matters for many Polish accountancy firms and people who, for a fee, help fellow Poles with their tax returns in the UK. Registration is free and done online, through an ASA application. Once you have applied and received a registration number, you can continue acting for clients while HMRC processes your case.

Risk

HMRC warns that unregistered advisers may have their ability to act for clients restricted and may face financial penalties. HMRC has not stated the amount of the penalties. If you use an adviser, make sure they are registered – otherwise your affairs could get stuck.

What to do

• Use the GOV.UK tool to check whether and when you need to register.
• If you do – apply for an ASA before 18 November.
• Check whether you meet HMRC’s registration conditions.
• Use an accountancy firm? Ask whether it is registered with HMRC.
• Do not pay anyone to “speed up” registration – it is free.

How to read this

The change does not affect an ordinary person who files their own tax return. It concerns those who earn money dealing with HMRC on behalf of others. If in doubt, it is best to use the official GOV.UK tool.

Contact us

Have a question or need help in Polish? Email [email protected], use the live chat on our website or call 07508 267866 (Mon–Fri 9:00–13:00 and 15:00–18:00, Sat 11:00–14:00).

Sources: GOV.UK / HMRC – second registration window for tax advisers; GOV.UK – check if you need to register; GOV.UK – apply for an ASA