Supergrass Law and Legal Definition

Supergrass is a term of English law and it refers to a person (usually a criminal) who gives information to the police about a large number of criminals. This slang term was widely used for a police informer by journalists in London. Recently, this term was used to describe an informant with the terrorist group 'Al-Qaeda' links testifying at the trials for seven British men conspiring to cause explosions between January of 2003 and March of 2004.