William Binney is one of the highest-level whistleblowers to ever emerge from the NSA. He was a leading code-breaker against the Soviet Union during the Cold War but resigned soon after September 11, disgusted by Washington's move towards mass surveillance.

On 5 July he spoke at a conference in London organised by the Centre for Investigative Journalism and revealed the extent of the surveillance programs unleashed by the Bush and Obama administrations.

"At least 80% of fibre-optic cables globally go via the US", Binney said. "This is no accident and allows the US to view all communication coming in. At least 80% of all audio calls, not just metadata, are recorded and stored in the US. The NSA lies about what it stores."