Intelligence agencies in the UK and the US are "out of control" and bypassing their own national laws by legally spying on each other's populations because current surveillance legislation has been overtaken by advanced interception technology.
Two of Britain's leading civil rights groups who are making these claims say the Government needs to update surveillance laws urgently to protect citizens. The demand from Liberty and Big Brother Watch follows the latest revelation from the US data security whistle-blower Edward Snowden, who claims the UK is the global leader in gathering vast amounts of data by accessing international fibre-optic cables.
In information given to The Guardian, Mr Snowden identifies the UK spy agency GCHQ as secretly processing data taken from the huge network of cables which carry telephone and internet traffic in and out of the UK and of sharing its analysis with its US counterpart, the National Security Agency.
Using technology codenamed Tempora, GCHQ, it is claimed, has been authorised over the past five years to place intercepts on almost 1,600 major fibre-optics cables that carry communications in and out of the UK. In theory, when the Tempora project is completed, GCHQ will have access to a daily flow of data equivalent to 192 times the British Library's entire book collection.
The accessed material includes phone calls, emails Facebook and other new media, and users' website history.
According to information reported to have been supplied by Mr Snowden, Tempora has allowed GCHQ to handle 600 million telephone events each day by tapping into fibre-optic networks. GCHQ maintains its targets remain diplomatic, military, commercial, terrorist and criminal threats to the UK's national security.
However, the way fibre-optics technology works means there is a legal grey area surrounding the wider legitimacy of Tempora since a large proportion of fibre-optics traffic is first relayed abroad, out of the UK, returning in a later part of the communications process.
Legislation brought in during 2000 allowed GCHQ to monitor telecommunications mainly related to fraud, drug trafficking and terrorism. However, as fibre-optics traffic has overtaken satellite interceptions, the legal safeguards on the data gathering and storage have failed to keep pace with accelerating technology.
The civil liberties group Liberty told The Independent on Sunday that the Snowden revelations indicated the UK intelligence services were "out of control but past caring". A spokeswoman added: "The current legislative framework was drawn up in a different era and has been wholly overtaken. Parliament must urgently inquire into these chilling details and demand new regulation to keep our nation free."
Nick Pickles, director of Big Brother Watch, said because text messages technically left the UK and then came back, GCHQ was "exploiting this technical change to subvert the will of Parliament and the law". "The UK has obligations under EU law to ensure there is protection in this area," he said. "But there is none."