Setting up sole proprietorship

Hello, I have few questions regarding this as i am very confused when it comes to legal things. I have regular job where i am full time employed and oay taxes and nin. 1) Can i set sole proprietorship? 2) If i make no profits or make just loss at the start do i have to pay extra for my business? 3) If i make profit, how and who should i contact in order not to overpay taxes and nin? 4) Will my full time job income be considered for my personal company or it will be completely separated from it? Kind regards, Stepan.

Hi 

1 - Yes.  As an employee of a company, you can choose to set up as a sole trader (self employed).  
2 - If your gross turnover exceeds £1000 in a tax year, then you need to register as self employed and submit a self assessment tax return.  You can do this at Set up as self-employed (a 'sole trader'): step by step
3 - See 2
4 - Both your employment and self employment are separate.  It is only when you complete your self assessment tax return, where you declare all of your 'world-wide income', that they are brought together by HMRC, to calculate how much tax and national insurance you owe.

Thank you