Self-employed workers still need to pay taxes to HMRC via a self-assessment.
Being self-employed means you are taxed on total profits, rather than the overall gross income. This means when it comes to submitting your self-assessment you'll need to take into account allowable business expenses. With this in mind, it's important to keep a record of your expenses throughout the year so that when it comes to submitting your self-assessment you have all the required information.
If you are specifically working via the CIS scheme, 20% of your gross income will be deducted on account, and paid to HMRC. We report this automatically to HMRC on our monthly returns. You will need to take into account the tax already paid when you come to complete your self-assessment. If you don't register under the scheme, the deduction reverts to 30%.
Regardless of your CIS status, you will be responsible for paying your own Income Tax & NI Contributions to HMRC directly.