Pay As You Earn (PAYE) is a collection mechanism applying to payments of employment and certain other income chargeable under the Income Tax (Earnings and Pensions) Act 2003. It operates by requiring tax to be deducted by employers at the time of payment. First introduced for 1944–45, PAYE has gone through a number of adaptations, most recently to digital systems and communications. To administer this considerable undertaking, HM Revenue and Customs (HMRC) deploy many thousands of staff and use sophisticated computer systems. There can be few adults in the UK who have not heard of or experienced PAYE.