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HMRC internal manual

Self Assessment Manual

HM Revenue & Customs
, see all updates

Records: agent record: introduction

All tax agents, advisors or accountants, who wish to act for their clients in respect of Self Assessment (SA), must be issued with an SA agent code. The allocation of agent codes has been centralised and the Agent Maintainer Team, within the Central Agent Authorisation Team (CAAT) at Longbenton, deal with the setting up and amending of all agent records for SA.

Local offices must not set up new agents on the SA database. The Agent Maintainer Team in CAAT, who have full access to the Agent Maintainer role in SA, must set up all new SA agents.

Only the SA agent code is entered on the customer’s SA record. Full details of the SA agent are held on the national database and can be retrieved when you enter the SA agent code onto the SA system (CESA).

To obtain an SA Agent Code, the new agent must write to HMRC and provide the business name, name of the partner/director of the business, address and telephone number together with confirmation that they require a Self Assessment Agent Code and send to

Agent Maintainer Team
Benton Park View
Newcastle Upon Tyne
NE98 1ZZ

Note: HMRC cannot accept this information by telephone, fax or online. Requests made using these methods will not be accepted. The request must be made in writing. All amendments to existing SA Agent Codes must also be made in writing and sent to the address above.

HMRC will send confirmation of the new agent code for that agent to use and the agent code should be quoted on all paper forms 64-8 and online authorisation for all new clients.

Full instructions for the Agent Maintainer team in CAAT are available in the National Insurance Procedural Guidance (NIPG) Manual and in NICO technical guidance.

The Agent Maintainer team in CAAT also deal with

  • All new SA agents with an address abroad, previously dealt with by CAR (PTI), formerly CAR (Residency)
  • New COTAX agents