The British government’s bulk collection of phone record metadata is facing a potential court battle after the legality of the scheme was challenged by Privacy International.

Under a filing from the civil rights advocacy the Investigatory Powers Tribunal , which regulates government snooping, will have to judge whether the programme is compatible with the European Convention on Human Rights.

In particular the case will revolve around sufficient safeguards have been set up to limit the use of such data by GCHQ and MI6, officially known as the Secret Intelligence Service (SIS).

Eric King, deputy director of Privacy International said: "Secretly ordering companies to hand over their records in bulk, to be data-mined at will, without independent sign off or oversight, is a loophole in the law the size of a double-decker bus.

"That the practice started, and continues without a legal framework in place, smacks of an agency who sees itself as above the law."

Responding to the challenge a spokesman from the Home Office argued that surveillance "is carried out in accordance with a strict legal and policy framework" that ensures such activities are "authorised, necessary and proportionate".

The case follows after a similar battle over mass phone metadata collection came to a head in the US Congress, which was prompted by the expiration of a clause in the Patriot Act, signed into law following the terrorist attacks on the World Trade Center in 2001.

Whilst attempts to renew the clause in the legislature failed, politicians rallied to pass the US Freedom Act, which will oblige telecoms companies to hold similar data and provide it to surveillance agencies on request.

"How can it be that the US is so much further ahead on this issue?" King asked. "With the USA Freedom Act now passed, the equivalent NSA power has now been curtailed before the debate this side of the pond has even begun."

Image courtesy of the Ministry of Defence