Statutory sick pay is paid to employees by their employer when they are sick and unable to work. You do not need to have paid national insurance contributions and it does not matter what other income you have. However, SSP is treated like any other earnings for income tax purposes.
SSP is paid at a fixed rate which for the current year is £79.15 a week. Depending on your circumstances you may also be able to claim income support, housing and council tax benefit or working tax credit.