The specific powers and duties of the Comptroller and Auditor General and the NAO are laid down in acts of Parliament.
The main acts of parliament are:
This laid out the means of appointing the C&AG; set up the Parliamentary Public Accounts Commission; established the NAO and set out how it would operate; allowed for the carrying out of value for money examinations; and provided for the NAO to be audited.
This act, and associated Statutory Instruments that have come after it, placed many of the C&AG’s existing audits on a more statutory footing, increased the numbers of Government bodies for which the C&AG was the auditor and widened the NAO’s rights of access to information for audit purposes to groups such as Government consultants.
In addition some provisions of earlier audit acts are still extant:
This act provides the legal authority for the C&AG to audit the taxes and duties collected by HM Revenue & Customs, the vehicle excise duties collected by the Driving and Vehicle Licensing Agency and the television license revenue collected by the BBC. As well as certifying the revenue accounts, the C&AG is required to ascertain whether the bodies responsible for collecting revenue have framed adequate regulations and procedure to secure an effective check on the assessment, collection and allocation of the revenues for which they are responsible; and to satisfy himself that such regulations an procedure are being duly carried out.
Other acts of Parliament require individual public bodies to be audited by the C&AG.