HM Revenue & Customs

What details do I need to register (sign up) for the Corporation Tax online service?

Organisation

To register (sign up) as an Organisation, you must enter your Corporation Tax Reference, and either your registered office postcode or your Companies House Registration Number (CRN):

Please note: When entering the CRN during registration (sign up) please leave out any preceding letters or leading zeros.

Example: CRN AB 00097609 should be entered as 97609

Agent

To register (sign up) as an Agent, you must enter your Corporation Tax Agent Reference Number and your postcode. Contact your local tax office if you don't have a Corporation Tax Agent Reference Number.