Corporation Tax for Agents: HMRC Online Services

How to register online for Corporation Tax for Agents and file your clients' Company Tax Returns through the service.


You must pay your clients’ Corporation Tax and related payments electronically. You also have to file your clients’ Company Tax Returns (including supporting documentation) online.

The HMRC Corporation Tax for Agents online service allows you to manage most aspects of their Corporation Tax affairs online.

You can use the service to:

  • file your clients’ Company Tax Returns using commercial software
  • view your clients’ Corporation Tax outstanding balance and accounting periods
  • view your clients’ Corporation Tax liabilities, payments and payment reference for each accounting period for up to 7 years
  • request authorisation for new clients online
  • remove any clients you no longer represent
  • view and download a list of your clients
  • view and change some of your clients’ details
  • change your own contact details
  • view a summary of the group’s liabilities and payments if a Group Payment Arrangement is in place

How to register for Corporation Tax for Agents

To use the Corporation Tax for Agents online service you need to:

  • have an agent code
  • be signed up for HMRC Online Services
  • set up agent authorisations for each of your clients

HMRC expects high standards that promote tax compliance from anyone who offers to represent or give advice to taxpayers.

How to get an agent code

You’ll need to register as an agent for Corporation Tax in writing. You’ll then receive a Corporation Tax agent code, known as an agent reference.

You’ll have to give the following information in your application:

  • full name
  • trading name (if different)
  • address that your activities are carried out from (this cannot be a PO Box address)
  • telephone number
  • email address
  • supervisor for the purposes of The Money Laundering Terrorist Financing and Transfer of Funds Regulation 2017 - details of Professional Body membership or HMRC Anti Money Laundering Supervision registration number
  • Self Assessment or company Unique Taxpayer Reference number (UTR)
  • details of which taxes you plan to deal with, for example, Self Assessment (you may need a separate agent code for each tax)

Your application may be rejected if you do not provide this information, or if HMRC is not reasonably satisfied with the information you have provided. HMRC will tell you, within 28 days of receiving your application if it has been successful or not.

If you lose your agent reference code, you should write to the Agent maintainer at the Central Agent Authorisation Team.

If you’re not registered for HMRC Online Services

You’ll need to sign up as a new user and add the service to your account.

If you already have an HMRC Online Services account

You can add Corporation Tax for Agents to your services:

  1. Sign in to HMRC Online Services.
  2. Go to ‘Your HMRC services’.
  3. Add ‘Corporation Tax for Agents’ to your portfolio from the ‘Services you can add’ section.

Set up agent authorisation through the Corporation Tax for Agents service

Once you’ve added the Corporation Tax for Agents service to your portfolio, you’ll have to get agent authorisation for any new or previously unauthorised client.

Sign in to Corporation Tax for Agents and follow the instructions under ‘Request an authorisation’.

You’ll need:

  • your client’s Corporation Tax Unique Taxpayer Reference number
  • either the postcode of your client’s registered office (main business address if no registered office) or their Companies House registration number
  • the authorisation code HMRC will send to your client’s registered office address by post - this code begins with ‘CT’ and you’ll need it to complete the authorisation process

The authorisation code can take up to 7 days to arrive. You’ll need to enter the code before the client will appear on your client list, so you need to do this in advance of their return filing deadline. You must enter the code within 30 days from the date on the letter.

How to file your client’s Company Tax Returns online

Most all companies and organisations must file their Company Tax Returns online and make any related payments electronically.

You can use Corporation Tax commercial software to file your client’s Company Tax Returns online.

How to use the Corporation Tax for Agents service when the company is in receivership or liquidation

You can continue to use the service when the company is in receivership.

If the company is in liquidation, you will not be able to use the service once HMRC has updated its records. However, the liquidator can use the service. They need to register the company for the service by following the process to register a single company, but the address used in the registration process should be the liquidators.

Guidance on Corporation Tax online filing

You may need more detailed guidance about some aspects of Corporation Tax online filing. For example if:

  • your software does not automatically insert all the iXBRL tags
  • you want to access the legislation and directions that underpin the mandatory online filing and electronic payment of Corporation Tax
  • you want to know what’s the right format to use to send your client’s accounts to HMRC
  • you need advice on managing the transition to filing online and using iXBRL
Published 1 January 2014
Last updated 22 January 2019 + show all updates
  1. The 'How to register for Corporation Tax for Agents' section has been updated with information on standards for agents.

  2. The regulation name in section 'How to get an agent code' has been updated to The Money Laundering Terrorist Financing and Transfer of Funds Regulations 2017.

  3. The 'Overview' and 'How to get an agent code' sections have been updated.

  4. Guidance on Filing your client’s Company Tax Returns online has been updated.

  5. Agent online services guidance has been updated to improve style and layout of content. HMRC Online Services log in information also updated in this guide.

  6. First published.