The Agent Dedicated Line is HMRC’s phone line for tax agents who are formally authorised to act for a client on Self Assessment or PAYE for individuals. It is on 0300 200 3311, Monday to Friday, 8am to 6pm. HMRC expects agents to use online services and webchat first, and an adviser will only discuss a client once they have found the agent’s authority on HMRC’s records and taken the caller through verification checks.

What is the agent dedicated line for?

HMRC’s GOV.UK page says agents should call about Self Assessment or PAYE if they are formally authorised to act as an agent or tax adviser for the client. Since 7 October 2024, according to ICAEW’s Tax Faculty, there has been one combined line covering both Self Assessment and PAYE queries, rather than separate options, together with a webchat service for agents and a separate option for chasing Self Assessment repayments.

HMRC publishes separate agent dedicated line pages for:

Line Use it for Number and hours
Self Assessment or PAYE for individuals Individual clients’ Self Assessment and PAYE coding, records and repayments 0300 200 3311, Monday to Friday, 8am to 6pm
Debt Management Discussing a client’s debts 0300 200 3887, Monday to Friday, 8am to 6pm

For a client’s tax debts see also HMRC Time to Pay arrangements. Paper authorisations go to the Central Agent Authorisation Team by post.

What should not go to the line?

HMRC’s page tells agents not to phone to check progress if the date by which they should receive a reply has not yet passed, and not to ask about tax or employment history that they can access online. HMRC’s “Where’s my reply?” tool gives the expected reply date for Self Assessment and several other areas, and lets agents check how long HMRC will take to process an application for authority to act for a client.

Much of what agents used to ring about can be done online:

  • Self Assessment for Agents: view a client’s PAYE coding notice, statements, liabilities and payments, claim to reduce payments on account, submit returns, change contact details and download the full client list.
  • PAYE for Agents: manage most of a client’s responsibilities, including the Construction Industry Scheme and Employment Related Securities.
  • Income Record Viewer: a client’s PAYE information for the current year and the 4 previous tax years, employment records including taxable benefits and gaps, and State and private pension information.

HMRC’s webchat for agents covers Self Assessment registration or reactivation, cancelling a Self Assessment record and Making Tax Digital for Income Tax.

How many clients can you raise in one call?

ICAEW reported that, from 7 October 2024, HMRC advisers deal with queries on a maximum of five taxpayers in one call or webchat, and that a single call or webchat may be capped at one hour. A practice with a longer list needs to batch queries across several calls.

Repayment chasing has its own rules. HMRC wants agents to check “Where’s my reply?” first and only call once the expected date has passed. ICAEW reported that some Self Assessment repayments are held for security checks that can take up to 12 weeks at peak times, and that advisers may not be able to give a progress update while a claim is being checked.

What security checks will the adviser carry out?

HMRC does not publish the exact questions. Its Debt Management and Banking Manual, which sets out how HMRC’s Debt Management staff handle calls, shows the general approach:

  1. Authority first. The adviser takes the caller’s name and reference and looks for authority on the client’s record, either a form 64-8 or a signed letter. Without it, nothing is disclosed and the agent is told to submit authority online or on paper to the Central Agent Authorisation Team.
  2. Caller verification. The adviser checks the agent’s details against the record and takes the agent through caller verification checks, confirming the answers match what is on screen. The specific questions are withheld from the published manual under Freedom of Information Act exemptions.
  3. Every call, every time. The manual says notes that HMRC has dealt with the agent before are not enough, because the client may have withdrawn the authority, so each contact must be verified.

Some further points from the same manual are worth knowing:

  • If the caller says they no longer work for the firm that holds the authority, the call must stop and someone from that firm must call instead.
  • HMRC’s Voice ID system, which lets some individual customers pass security by voice, is not available to agents and accountants.
  • Authority given before a client’s death, such as a 64-8, no longer allows HMRC to disclose information; the personal representatives must give fresh consent.
  • If HMRC phones an agent and the agent wants proof the call is genuine, HMRC staff are told to ask the agent to call back on the appropriate published number.

How does authorisation affect what HMRC will discuss?

The line is only for agents who are already authorised. Authorisation now runs mainly through the agent services account, and anyone who interacts with HMRC about someone else’s tax affairs and is paid for it must meet the tax adviser registration requirements. Authority is held against a legal entity. When HMRC asked firms to confirm their agent codes in 2024, ICAEW’s Tax Faculty warned that firm mergers, takeovers and other changes might mean obtaining fresh authority from clients in the name of the correct legal entity. An adviser who cannot find authority in the name of the caller’s firm will not proceed.

How should a practice protect its agent access?

HMRC has warned that agent accounts are often a target for fraudsters and, as ICAEW reported, may suspend an account without notice if it believes it has been compromised. HMRC’s guidance says it will never ask for an agent’s password, and that agents should use their own agent registration rather than clients’ sign in details, keep administrator lists up to date, sign in through the web rather than links in emails, and report suspicious activity rather than trying to correct it themselves. If an account has been suspended and no letter has arrived, ICAEW says agents can call HMRC’s online services helpdesk on 0300 200 3600. The same discipline protects clients from payment scams; see preventing payment diversion fraud and the HMRC Standard for Agents.

What does a well prepared call look like?

Illustration only. A practice has seven clients with incorrect PAYE codes. A staff member first checks the Self Assessment for Agents service and the Income Record Viewer, which resolves two cases. For the remaining five, she confirms each client’s authority is showing in the firm’s name, gathers the UTRs and National Insurance numbers, writes down the specific question for each and calls the line. She passes the verification checks, deals with all five within the hour, and records the adviser’s name, the time and the outcome on each client file. A sixth client’s repayment query waits until the “Where’s my reply?” date has passed.

What mistakes do agents make?

  • Calling to chase before the “Where’s my reply?” date, which HMRC asks agents not to do.
  • Ringing about information that is available online.
  • Bringing more than five clients to one call.
  • Calling for a client whose authority is held by a former firm or a predecessor legal entity.
  • Using a client’s own sign in details instead of agent access.
  • Not recording who at HMRC said what, which makes later disputes hard to resolve.

Solar Protect runs fee protection schemes for accountancy and bookkeeping practices. See how our accountant schemes work or read fee protection schemes for accountants.

Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.