Question to the HM Treasury:

To ask the Chancellor of the Exchequer, whether HM Revenue and Customs uses fully automated processes to (a) calculate under or overpayments of tax and (b) notify taxpayers of such under or overpayments of tax..

At the end of each tax year HMRC reconciles the PAYE accounts of individual customers who are outside Self-Assessment. This exercise is called End of Year Reconciliation. Information used includes the final pay and tax deductions for the year as reported by employers, alongside taxable benefits and any additional income/benefits supplied by the individual customer. In addition, HMRC carries out assurance checks to ensure that the calculation is correct. Some re-calculations may be necessary if the position has changed, for example, due to further changes to income, expenses claims, or benefits.