The government insists that UK spy agencies operate within the law in response to concerns about links to the US Prism internet monitoring programme, but questions remain.
Documents leaked by former CIA technical assistant Edward Snowden suggest UK intelligence agency GCHQ has had access to the US Prism surveillance operation since June 2010.
In the course of a year, the agency is reported to have generated 197 intelligence reports using Prism, set up to monitor nine internet firms including Google, Facebook, Microsoft and Apple.
In a statement to the House of Commons, however, foreign secretary William Hague made no comment about GCHQ’s access to Prism, set up by the US National Security Agency (NSA).
“Any data obtained by us from the US involving UK nationals is subject to proper UK statutory controls and safeguards,” he said.
Hague also failed to address concerns over the regulatory system in which intelligence agencies work or to draw a distinction between the different types of data being gathered.
Instead, he said there was a strong framework of democratic accountability and oversight that governs the use of secret intelligence in the UK.
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These checks include the Intelligence Services Act of 1994 and the Regulation of Investigatory Powers Act (RIPA) of 2000 that require agencies to seek authorisation for operations from a secretary of state.
"To intercept the content of any individual's communications in the UK requires a warrant signed personally by me, the home secretary, or by another secretary of state,” said Hague.
However, the data gathered by the NSA’s phone call monitoring activities does not include content, and therefore access to data about the time and place of calls does not require ministerial approval.
In 2012, law enforcement agencies made 500,000 information requests from telecoms companies, which is a massive amount of raw data being held without extensive legal advice, said the Guardian.
Critics argue that the current system relies on politicians, an under-resourced parliamentary committee, and commissioners who do not have enough staff to make the right decisions, the paper said.
Privacy International said it should not take a whistleblower releasing classified information for the government to be forthright with its citizens about what data they collect and in what manner.
"If the government secretly interprets the law, and if the manner in which it is executed is secret, then the law is effectively secret. There are many questions that remain unanswered," the group said.