The secretive UK investigatory powers tribunal has begun its hearings into the legality of mass surveillance conducted by tapping fiber optic lines, through a Snowden-revealed programme called TEMPORA.
The challenge to TEMPORA was brought by an international coalition of civil liberties groups, including Privacy International, Liberty, the ACLU, Amnesty International and others. The spy agencies' representatives have told the court that they will not confirm or deny the existence of TEMPORA.
In defence documents already submitted, the government's most senior security official, Charles Farr, has explained how searches on Google, Facebook, Twitter and YouTube, as well as emails to or from non-British citizens abroad, can be monitored legally by the security services without obtaining an individual warrant because they are deemed to be "external communications".
The IPT hearing, at the Rolls Building in central London, may hear some of the most sensitive evidence about interceptions in private. This claim is expected to concentrate on the legality of two interception programmes, Tempora and Prism, and their use by the UK's monitoring agency, GCHQ, and its US counterpart, the NSA.
In Farr's submission, he says he can "neither confirm or deny" the existence of Tempora, although he does acknowledge that Prism exists "because it has been expressly avowed by the executive branch of the US government".
GCHQ surveillance hearing to begin [Owen Bowcott/Guardian]