A report from the Public Accounts Committee (PAC) says HM Revenue and Customs (HMRC) underestimates the number of tax reliefs and does not properly count their cost. The taxman does not check sufficiently to see if the reliefs are being abused, the MPs add. The PAC said that HMRC does not know how many reliefs exist or their cost. The huge burden of tax reliefs on the public purse is an issue that receives relatively little attention. These are exemptions from tax law that are either designed to make the tax system fairer, such as the income tax personal allowance, or which are intended to change people’s behaviour, such as tax reliefs for pension contributions, the newly announced personal savings allowance, or the various reliefs to encourage business investment.