If you are Self Employed you are taxed on the following profits and gains.
Salary/Wages from Employment Employment Benefits
Profits from self-employed earnings (ie. an products or services which you charge for)
State, company & personal pensions
Interest on savings and bonds (other than tax free ISAs)
Rental income (unless you are living in the property and receive less than £4250 per annum from your lodger)
Income from trusts
Dividends corporate shares