PAYE (Pay As You Earn) is a system that is used in the United Kingdom to collect income tax and National Insurance contributions from an individual's salary or wages. The PAYE system is administered by HM Revenue and Customs (HMRC), and it is used to ensure that individuals pay the correct amount of tax on their income.

Under the PAYE system, an individual's employer is responsible for deducting the appropriate amount of tax and National Insurance contributions from their salary or wages and for paying the deductions to HMRC on the individual's behalf. The tax and National Insurance contributions are calculated based on the individual's tax code and the tax rates and bands that are in effect for the tax year.

If an individual's tax code or tax deductions are incorrect, they may have to pay more tax than they should or may be entitled to a tax refund. It is important to check your tax code and tax deductions regularly to ensure that they are correct and to contact HMRC if you spot any errors or discrepancies. If you have any questions about the PAYE system or need help with your tax return, you can contact HMRC for assistance.