If you run your own business as a sole trader (rather than through a company) you should register for self-assessment so that HMRC can issue you with an annual tax return. Because you do not pay tax at source (unlike employees who face a tax deduction through PAYE) you need to complete a tax return and pay your tax every six months. Even if your income is so low that you do not need to pay tax you will need to notify HMRC and complete the tax return they issue.
To find out more, call us on +44 (0)330 024 3200 and speak to one of our personal tax experts.