I am currently a freelance school adviser and now advised as being inside the IR35 in one of my schools. My query is what happens if I don't exceed the tax threshold (last year I earned just over £10000). School have they will take basic rate of tax off my invoice - but do I then have to claim tax back after completing my self assessment? Sorry - it was so much easier completing the self assessment and paying NI contributions, this just seems to complicate things!