Atax reference number refers to a unique number given by a tax authority to either a person or a business. In the UK, this usually refers to the 10 numbers unique taxpayer reference (UTR), issued by HMRC. It is used for handling tax affairs such as submission of tax returns and liaising with HMRC. The number makes sure that the tax records are accurate and related to the right tax payer. It is recommended to protect your tax reference number and not misplace it, as it is usually needed for diverse financial and legal actions.