How to Authorise a Tax Agent in the UK: HMRC Guide

Authorising a tax agent is the formal process of giving an accountant or adviser permission to deal with HM Revenue & Customs (HMRC) on your behalf. While a majority of businesses rely on agents for their expertise and efficiency, navigating the authorisation process itself is a critical step.

Whether you’re engaging an accountant for the first time or switching providers, understanding the correct procedures is essential for secure and compliant tax management.

The crucial point to remember is that even with a duly authorised agent, you, the taxpayer, remain legally responsible for your own tax returns and payments.

This guide breaks down the methods of authorisation, the responsibilities involved, and what you need to do to get set up correctly in 2026.

The Core Methods of Authorisation: Digital vs. Paper

HMRC has moved significantly towards digital processes. The method you use will depend on the specific tax service and your agent’s setup.

The Digital Handshake: A Step-by-Step Guide

The “digital handshake” is HMRC’s modern, secure standard for authorisation. The process is straightforward and is managed almost entirely online.

For the Agent:

1. Have an Agent Services Account (ASA): An agent must have an ASA to use HMRC’s digital services for agents. This is separate from older HMRC online accounts.
2. Initiate the Request: The agent signs into their ASA and selects the option to ‘ask a client to authorise you’ for the relevant tax service.
3. Generate and Send Link: They enter your client details, which generates a unique, time-limited authorisation link. This link is then sent to you (the client) directly.

For the Client:

1. Receive the Link: You will get the authorisation link from your agent, usually via email. For some services, this link may expire (e.g., after 21 days for the CGT on UK Property Account).
2. Log in and Approve: Click the link and use your Government Gateway user ID and password to sign in. You will be prompted to review and approve (or reject) your agent’s request.

Once you approve the request, the agent is authorised and can manage the specified service on your behalf.

What Are the Key Considerations for Agent Authorisation

Your Legal Responsibility Never Ends

Appointing an agent does not transfer your legal duties to them. You are still responsible for ensuring your returns are accurate and submitted on time, and that any tax due is paid. Your agent provides advice and support, but the ultimate liability remains with you.

Scope of Authority

An agent’s authorisation is often specific to a particular tax. It is common for an agent to be authorised for your Self Assessment but not for PAYE, or vice-versa. This is particularly important if you use different specialists for different areas of your tax affairs. For example, a company may have one main agent for submitting returns and a second, specialist agent to handle a compliance enquiry.

Making Tax Digital (MTD) and Multiple Agents

MTD for Income Tax Self Assessment (ITSA) introduces a more flexible agent model:

• Main Agent: Has full access to manage a client’s MTD for ITSA affairs, including finalising and submitting the tax return.
• Supporting Agent: Has limited access, typically to view business income details and submit quarterly updates. A bookkeeper might act as a supporting agent, while your accountant is the main agent.

A client can have only one main agent for MTD for ITSA at a time but can have multiple supporting agents.

Changing or Removing an Agent

Agent authorisation continues until it is actively cancelled by either you or your agent.

• Clients can remove an agent’s authority via their Government Gateway account (under ‘Manage who can deal with HMRC for you’).
• Agents can remove a client from their list via their Agent Services Account.

To appoint a new agent, the authorisation for the previous agent should be removed first before the new one is granted.

Frequently Asked Questions (FAQs)

Q: What is an Agent Services Account (ASA)?

An Agent Services Account is the digital account that allows tax advisers to access modern HMRC online services and manage client authorisations. It is essential for any agent dealing with MTD or the CGT on UK Property Account.

Q: Can a business have more than one tax agent?

Yes. For Corporation Tax, a company can authorise multiple agents, each with a defined “period of responsibility” for specific accounting periods. For MTD for ITSA, individuals can authorise one main agent and several supporting agents.

Q: What happens to my agent’s authorisation if I die?

Any existing authorisation automatically becomes invalid from the date of death. The personal representative or executor of the estate must grant a new authority if they wish for the agent to continue acting.

Q: How long does agent authorisation last?

Generally, authorisation remains in place until it is actively cancelled. However, HMRC has explored concepts like time-limited authorisations (e.g., requiring renewal every two years), so this could change in the future for certain services.

This article is intended to provide a general overview. The specific processes can vary between different tax regimes and are subject to change by HMRC.

For agents, the process starts with securing an Agent Services Account. Further guidance can be found on GOV.UK under ‘Apply for an agent services account’. For specific taxes, such as MTD for Income Tax or the CGT on UK Property Account, HMRC manuals provide detailed step-by-step instructions.