Controversial surveillance powers employed to fight terrorism and combat crime have been misused by civil servants in undercover "spying" operations that breach official guidelines, the Guardian has learned.
Documents obtained under Freedom of Information show some government departments and agencies have used these powers incorrectly or without proper controls. They also show the official government watchdog set up to monitor the use of such clandestine techniques criticised the departments for their behaviour.
Civil servants attacked for using anti-terror laws to spy on public
