This study offers a new and detailed examination of parliamentary scrutiny of the British intelligence and security agencies. Through detailed analysis of parliamentary business, coupled with interviews with MPs, peers and senior officials, it examines the various mechanisms by which parliament seeks to scrutinise the secret state, and assesses the extent to which parliament has both the capacity and the will to provide effective oversight of intelligence and security policy and agencies. In addition to providing a detailed analysis of the impact of the Intelligence and Security Committee, this is the first book to examine the various other means by which a range of parliamentary bodies including select committees, all-party groups and individual parliamentarians have sought to scrutinise the intelligence agencies and the handling of intelligence by government.