I live in the UK and I'm thinking of starting a business whilst in full time employment.

I've looked up the tax rules but I'm still quite unsure on everything. I was hoping someone could just clear up any misunderstandings I have.

I have two main questions:

1. If I start a business and I pay myself a salary from that business, does the tax amount get calculated based on my current salary as well? So if I currently get taxed 40% will everything I earn from the new business immediatly get taxed at 40% because of my current job?

2. If instead of paying myself a salary I pay myself in dividends, how much would that be taxed and will it be affected by my current jobs tax?

Regards,