If you are running your own business as a sole trader or as part of
a partnership, you will be treated as self-employed for tax purposes.
You need to register your business with HM Revenue and Customs
(HMRC) within three months of beginning to trade to avoid an automatic
penalty being imposed. HMRC will then send you a self-assessment
tax return or a notice requiring you to complete a return each 6 April.
This factsheet gives guidance on preparing for and completing your
tax self assessment return. It also offers hints and tips, and lists
sources of useful information.