A Parliamentary watchdog will today grill security chiefs after details of their widespread snooping were revealed by the Guardian.
The Intelligence and Security Committee has decided to extend its investigation as to whether current laws on intercepting private communications were adequate.
An earlier hearing found GCHQ was not using US internet monitoring software to by-pass UK laws.
However, information published from NSA whistleblower Edward Snowden in the Guardian reignited the debate and prompted today’s hearing.
Committee chairman Sir Malcolm Rifkind said: “The Intelligence and Security Committee of Parliament announced – as part of its statement on Prism, issued in July – its intention to do further work on the legislation which governs the security and intelligence agencies' access to the content of private communications, including to determine whether the relevant Acts of Parliament are still 'fit for purpose' given the developments in information technology since they were enacted.
"In recent months concern has been expressed at the suggested extent of the capabilities available to the intelligence agencies and the impact upon people' s privacy as the agencies seek to find the needles in the haystacks that might be crucial to safeguarding national security.
"There is a balance to be found between our individual right to privacy and our collective right to security. An informed and responsible debate is needed. The Intelligence and Security Committee of Parliament has therefore decided to broaden the scope of its forthcoming inquiry to consider these wider questions, in addition to those relating to the existing legislative framework.”
Rifkind, who previously served as Secretary of State for Defence and Foreign Secretary, said the committee would consider classified information as well as submissions from the public before reaching their conclusion.”
Shami Chakrabarti, director of civil liberties campaigners Liberty, said: "This watchdog makes friends and does not always bark in the night.
"Some will say better late than never, others fear a tactical whitewash to calm public concern.
"It's certainly significant that the committee feels compelled to dig a little deeper but that's no substitute for much broader public and political debate.
"Public safety requires proportionate surveillance but the watchers need watching too."
However, despite the Parliamentary investigation into the nation’s spies, Downing Street still maintains the Guardian was wrong in publishing the Snowden files.
During Prime Minister Questions yesterday, David Cameron said: “The plain fact is that what has happened has damaged national security and in many ways the Guardian themselves admitted that when they agreed, when asked politely by my national security adviser and cabinet secretary, to destroy the files they had, they went ahead and destroyed those files.
“So they know that what they’re dealing with is dangerous for national security. I think it’s up to select committees in this house if they want to examine this issue and make further recommendations.”
This claim drew an angry response from the Guardian who said they were forced to scrap their hard drives.
“The Prime Minister is wrong to say the Guardian destroyed computer files because we agreed our reporting was damaging.
“We destroyed the computers because the Government said it would use the full force of the law to prevent a newspaper from publishing anything about the NSA or GCHQ.
“That is called ‘prior restraint’ and it is unthinkable in the US, where the New York Times and Washington Post have been widely applauded – along with the Guardian – for reporting on the Snowden files. That reporting has so far led to a presidential review and three proposed bills before Congress.”