How to get authorised to act as a tax agent on behalf of your clients
Source: gov.uk (2025-09-08)

Find out the different ways you can get client authorisation including the digital handshake, Online Agent Authorisation service, paper forms and through your client's business tax account.

Once you’ve registered as a tax agent (https://www.gov.uk/guidance/find-out-how-to-register-as-a-professional-tax-agent-with-hmrc), you must then get authorisation from your client so that you can transact for them.

You should not use your client’s HMRC sign in details or access their online tax account.

If your client is digitally excluded, give them the authorisation request link and a number to contact HMRC (https://www.gov.uk/contact-hmrc). Your client will be passed through to the Extra Support Team, who will talk them through the process over the phone.

Find out the different ways to get client authorisation

Depending on which tax services you will be using, there are different ways to get authorisation from your clients, including:
- the digital handshake
- online
- asking your client to authorise you through their business tax account
- paper forms
Follow these steps to help you get authorised.

Use the table to find out the different ways you can get authorised for the tax service you need.

Follow the instructions after the table on how to get authorised.

If you’re using the Stamp Taxes service, you do not need to get authorisation from your client to submit a return using the online service (https://www.gov.uk/sdlt-online).

Using the digital handshake to get authorised

Find out how to use the digital handshake to get client authorisation (https://www.gov.uk/guidance/how-to-use-the-digital-handshake-to-get-authorised-as-a-tax-agent).

Using Online Agent Authorisation to get authorised

Find out how to use Online Agent Authorisation to get client authorisation (https://www.gov.uk/guidance/how-to-use-the-online-agent-authorisation-to-get-authorised-as-a-tax-agent).

Getting authorised through your client’s business tax account

You can ask your client to authorise you through their own business tax account. They will need your agent Government Gateway Identifier to do so. You can find this by completing the following steps.

Sign into your HMRC online services for agents account (https://www.gov.uk/log-in-register-hmrc-online-services).

Select ‘Authorise client’.

Find your identifier on the next screen under the title ‘Agent Identifier’.

Get authorised using online services, online forms or paper forms

If you need to get authorised using an online service, online forms or paper forms, you can do this by using the:
- ATED digital handshake (https://www.gov.uk/guidance/register-for-the-annual-tax-on-enveloped-dwellings-online-service) or the ATED1 paper form (https://www.gov.uk/government/publications/annual-tax-on-enveloped-dwellings-ated-1) for ATED
- ChV1 online or paper form (https://www.gov.uk/government/publications/charities-change-of-details-form-chv1) for charities
- CH995 online or paper form (https://www.gov.uk/government/publications/child-benefit-authorise-a-tax-adviser-for-high-income-child-benefit-charge-matters-ch995) for High Income Child Benefit
- TC689 online or paper form (https://www.gov.uk/government/publications/tax-credits-and-child-benefit-allow-someone-else-to-act-for-you-tc689) for Tax Credits and Child Benefit
- Comp1 online form (https://www.gov.uk/government/publications/compliance-checks-temporary-authorisation-comp1) for temporary authorisation for a compliance check
- 64-8 paper form (https://www.gov.uk/government/publications/tax-agents-and-advisers-authorising-your-agent-64-8) for Corporation Tax, Individual PAYE or National Insurance, PAYE, Self Assessment and VAT
- letter of authority (https://www.gov.uk/guidance/authorising-an-agent-to-deal-with-your-tax-affairs) from your client if you are only dealing with one specific area of a particular tax, but not acting as a full tax agent on our records