Former US Secretary of State Hilary Clinton has called for a “sensible adult conversation” on the boundaries of state surveillance that were revealed by whistle-blower Edward Snowden, who leaked secret NSA files earlier this year.

Mrs Clinton said it would be “going down wrong path” to reject a debate in the wake of disclosures about the collection of communications data by the America’s National Security Agency (NSA) and GCHQ, the UK government’s intelligence agency.

Speaking at Chatham House, where she collected a prize for her contribution to international diplomacy, she told The Guardian: "This is a very important question. On the intelligence issue, we are democracies thank goodness, both the US and the UK.

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"We need to have a sensible adult conversation about what is necessary to be done, and how to do it, in a way that is as transparent as it can be, with as much oversight and citizens' understanding as there can be."

"It would be going down a wrong path if we were to reject the importance of the debate, and the kinds of intelligence activities that genuinely keep us safe.”

She stated that citizens need to be “better informed,” and said that the question of surveillance was one that had not been dealt with for a decade.

Her comments come as Deputy Prime Minister Nick Clegg is seeking a rethink of the way politicians oversee the agencies, while Business Secretary Vince Cable called for "proper political oversight" of the intelligence services. Mr Cable said the Guardian newspaper had performed "a very considerable public service" in publishing secret material leaked by Mr Snowden, which revealed the extent of mass surveillance programmes operated by the NSA and Cheltenham-based GCHQ.

However, Sir David Omand, the former head of GCHQ who was once homeland security adviser to Number 10, said the leak of tens of thousands of files by the former US intelligence operative eclipsed the Cambridge spy ring, which saw five university students recruited as Soviet spies.

Highlighting possible future tensions, David Cameron has said he remains satisfied with the current system. Earlier this week Mr Cameron said: "If people want to suggest improvements I am very happy to listen to those, but as far as I can see we have a very good system." The Prime Minister's spokesman confirmed there was no official Government review, despite Mr Clegg’s request.

Mr Snowden, has remained in Russia following his information leak to the Guardian in May that revealed mass surveillance programmes such as the NSA-run Prism and GCHQ's Tempora.

Under the £1 billion Tempora operation, GCHQ is understood to have secretly accessed fibre-optic cables carrying huge amounts of internet and communications data and shared the information with the NSA.