I am a Sole Trader, and have invoiced a school for some work I have done. They have told me that they need my UTR on every invoice as they say they must comply with HMRC requirements and ensure that supplier that we trade with are complying the Tax laws. From what I understand, my UTR is a highly confidential piece of information and fraudulent use could leave me liable to someone else's taxes. I don't see how this number allows them that to check if I am complying with Tax Laws, as they can't check anything with it? But is a risk to me? Can I refuse to give it? Any advice?