Anyone acting as a tax agent or adviser must have formal authorisation to deal with HMRC on their client’s behalf. There is no `one size fits all’ and different authorisation procedures apply for different taxes.
The easiest way to apply for authorisation is to use HMRC’s online service. However, before this can be done, the agent needs an agent code or reference number– and a different code is needed for different taxes. Applications for codes for self-assessment and corporation tax must be made in writing, whereas the application can be made online for PAYE and CIS. Where the agent is VAT registered, his or her VAT number can be used for VAT authorisation requests, otherwise a VAT code must be obtained. This too can be done online.
For some clients it may not be possible to obtain authorisation online, and paper forms can be used instead. Form 64-8 is used for most purposes, although form FBI1 is used for PAYE matters and form CH995 for the high income child benefit charge. The agent code is needed on forms 64-8 and FB1.