The Public Accounts Committee (PAC) was set up in 1861 to examine that the sums of money agreed by Parliament for public spending were properly spent.
Since the passage of the National Audit Act in 1983 the committee's main function has been to examine the reports issued by the Comptroller & Auditor General (C&AG).
The C&AG checks the spending of government departments. If the Ministry of Defence orders a new fleet of helicopters, for example, the C&AG might check that the most cost effective option was chosen.
The Public Accounts Committee has fifteen members and, by tradition, the chairman is chosen from the Opposition.