This GCHQ document from November 2008 provides a guide to the legal authorisations required for different forms of agency activity: see the Intercept article Spies Hacked Computers Thanks to Sweeping Secret Warrants, Aggressively Stretching U.K. Law, 22 June 2015.
UK MPs have been told that, not only is the legal regime governing GCHQ likely to be incompatible with the European Convention on Human Rights, many of the agency’s activities are illegal even by current domestic standards.
Jemima Stratford QC and Tim Johnston were asked to prepare the opinion for the All Party Parliamentary Group (APPG) on Drones. While APPGs have no formal powers within the UK political system some – like the APPG on Extraordinary Rendition – have done important investigatory work in areas where formal oversight has been lacking.
While legislative proposals based on this opinion have already been tabled, its primary importance is likely to be its foreshadowing of issues the European Court of Human Rights (ECtHR) could adjudicate on this year in the case Big Brother Watch v United Kingdom. In the past, the Strasbourg court has played a decisive role in forcing changes to UK surveillance practices and it has never before been asked to consider the legality of mass surveillance.