Do I need to register as self employed?
Self employed people have to register with HM Revenue and Customs (HMRC) to pay tax.
This won't register you are self employed for benefits purposes.
There is no one way to register as self employed for benefits. You should tell each organisation (for example, the Department for Work and Pensions (DWP), HM Revenue and Customs (HMRC) or your local council) that pays you benefits that you are self employed and you should let them know your income from self employment.