HM Revenue & Customs

Can I use my existing Self Assessment Unique Taxpayer Reference (UTR) to register my business online?

Yes, if you have an existing UTR and are registered for Self Assessment because, for example, you receive income from property and were not self-employed at the time you registered, you can use that same UTR to now register a new business online for Self Assessment.

But, if you signed up for an individual Government Gateway account (User ID and password) to allow you to file your Self Assessment tax returns online under that UTR, you cannot use this individual account to register the business online. You must first de-enrol for Self Assessment under this account and apply for a new organisation User ID and password.