The foreign secretary insists Britain’s GCHQ listening post has not been using America’s Prism internet monitoring system to get around legal restraints on surveillance.
Mr Hague refused to confirm or deny details of the British eavesdropping agency’s links to the US spy scheme, but insisted the public have “nothing to fear” from GCHQ’s activities.
He said he would make a statement to the House of Commons on Monday on the issue.
He told the BBC’s Andrew Marr Show: “As someone who knows GCHQ very well… the idea that in GCHQ people are sitting working out how to circumvent a UK law with another agency in another country is fanciful. It is nonsense.”
The Foreign Secretary declined to confirm that he had personally authorised analysts at GCHQ to work with the US Prism programme.
But he said legal checks in place in this country, including reviews of decisions by the interception commissioner, were strong.
The net effect is that if you are a law abiding citizen of this country going about your business and personal life you have nothing to fear about the British state or intelligence agencies listening to the content of your phone calls or anything like that. William Hague
“That legal framework is strong, that ministerial oversight is strong.
“The net effect is that if you are a law abiding citizen of this country going about your business and personal life you have nothing to fear about the British state or intelligence agencies listening to the content of your phone calls or anything like that.
“Indeed you will never be aware of all the things that these agencies are doing to stop your identity being stolen or to stop a terrorist blowing you up tomorrow.”
He added: “If actually we could tell the whole world, or the whole country how we do this business I think people would be enormously reassured by it and they would see that the law abiding citizen has nothing to be worried about.
“But if we did that it would defeat the object. This is secret work. It is secret for a reason.”
The Prism system is said to give America’s National Security Agency and the FBI access to data stored by top internet companies, including Google, Facebook, Microsoft and Apple.
The Guardian said it had seen documents showing that GCHQ had access to the Prism system since at least June 2010.
The British agency, based at Cheltenham, was said to have generated 197 intelligence reports through the system in the 12 months to May 2012 – a 137 per cent increase on the previous year.
The newspaper said Prism appeared to allow GCHQ to get around the formal legal process required to obtain personal material like emails, photographs and videos from internet companies based outside the UK.