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The law

GCHQ acts in accordance with UK law.
GCHQ's functions - what we can do - are set out in the Intelligence Services Act 1994 (ISA).
We are primarily a foreign-focused intelligence agency, with a signals intelligence role that can only be exercised for three limited purposes:
  • In the interests of national security
  • In the interests of the economic well-being of the UK
  • In support of the prevention or detection of serious crime.
GCHQ also has a role providing advice and assistance (known as Information Assurance) to certain UK bodies, as set out in the ISA, for the protection of communications here in the UK.
The ISA also set up the Intelligence and Security Committee, which was recently replaced by the Intelligence and Security Committee of Parliament (ISC), the parliamentary oversight body which scrutinises GCHQ.
The ISC is an all-party Committee. It was originally set up to examine the expenditure, administration and policy of the three intelligence and security agencies - GCHQ, MI5 and the Secret Intelligence Service (MI6), but its functions were recently increased under the Justice and Security Act 2013 (JSA) to provide for further access and investigatory powers.
The Human Rights Act 1998 (HRA) requires public bodies, like GCHQ, to protect citizens' rights under the European Convention on Human Rights - GCHQ always acts in a way which is consistent with the HRA, supported by internal training, cuture and ethics procedures.
Interception of communications operations are authorised under the Regulation of Investigatory Powers Act 2000 (RIPA). Warrants authorising interception can only be issued by a Secretary of State. Before an interception warrant can be issued the Secretary of State must believe that a warrant is necessary on certain, limited grounds and that the interception is proportionate to what it seeks to achieve. These grounds are that interception is necessary:
  • In the interests of national security; or
  • In the interests of the economic well-being of the UK; or
  • In support of the prevention or detection of serious crime.
RIPA also requires safeguards to be in place to limit the use of intercepted material and related communications data.
RIPA sets out the functions of two independent Commissioners, senior judges who have oversight of GCHQ's activities; the Interception of Communications Commissioner and the Intelligence Services Commissioner. GCHQ has a duty to cooperate with those Commissioners and to disclose all such documents and information they might require.
GCHQ is also under the same duty to disclose in respect of the Investigatory Powers Tribunal (IPT), which is where proceeedings for certain HRA claims can be brought, and is the appropriate Tribunal to consider any complaints submitted to them about GCHQ and others.