HMRC advised that requests for a new or amended agent code must be made in writing - on headed notepaper if appropriate. HMRC will not accept information provided on form 64-8 to create or amend a code nor will they accept requests by to do so by phone, email, fax or through the online account.

Before an Agent can set up client authorisations for Self-Assessment, Corporation Tax and PAYE/CIS, an agent code must be obtained. This applies whether the Agent is using the online service or the paper route for authorisation. A separate agent code is required for each tax.

An agent code - or agent reference number - is specific to the agent and the relevant HMRC business area. For example, if a Self-Assessment agent code is requested, this should be quoted on all Self-Assessment client authorisations. This will assist HMRC in updating their records accurately and will enable an Agent to easily add new clients to their online client list.

For more information on how to obtain an Agent code for each tax head go to http://www.hmrc.gov.uk/agents/authorisation/setup.htm#2