High Quality Content by WIKIPEDIA articles! The Security Service, commonly known as MI5 (Military Intelligence, Section 5), is the United Kingdom`s internal counter-intelligence and security agency and is part of its core intelligence machinery alongside the Secret Intelligence Service (SIS or MI6) focused on foreign threats, Government Communications Headquarters (GCHQ) and Defence Intelligence (DI). All come under the direction of the Joint Intelligence Committee (JIC). The service has a statutory basis in the Security Service Act 1989 and the Intelligence Services Act 1994. Its remit includes the protection of British parliamentary democracy and economic interests, counter-terrorism and counter-espionage within the UK. Although mainly concerned with internal security, it does have an overseas role in support of its mission.