British intelligence leaders were questioned at a public hearing earlier today about their involvement with the mass data-collection programs detailed in documents leaked by Edward Snowden, reports the BBC. Such hearings usually occur in private, reportedly making the public broadcasting of this hearing unprecedented. The heads of MI5, MI6, and the GCHQ — Andrew Parker, Sir John Sawers, and Sir Iain Lobban — were present, and defended the surveillance programs as legal, contained, and necessary for national security.

Parker said that 34 terror plots had been stopped since the London bombings in 2005, one or two of which aimed to cause mass casualties, reports the BBC. Since the Snowden leaks, Lobban says that activists in the Middle East and some "closer to home" have started discussing how they can avoid communication channels that they believe are being monitored.

Lobban also denied accusations that the GCHQ — the British spy agency said to work closely with the NSA — was involved with mass surveillance. "We do not spend our time listening to the telephone calls or reading the emails of the majority," Lobban told the Parliament's Intelligence and Security Committee, according to the BBC. "That would not be proportionate, that would not be legal, and we would not do it." He also said that the people employed by the GCHQ would "walk out" if they were asked to spy on innocent people.

Parker agreed with Lobban, saying that they only address direct threats to the country. "The suggestion that what we do is somehow compromising freedom and democracy — of course we believe the opposite to be the case," Parker reportedly said.

Though the Intelligence and Security Committee found that the GCHQ's activities, in all of the instances that it has examined, have been legal, the BBC reports that it's now evaluating whether surveillance laws need to be updated for modern technology. The 90-minute hearing was reportedly televised with a two-minute delay to ensure that no sensitive information was inadvertently released. The committee's chairman remarked that it was a "very significant step forward in the transparency of our intelligence agencies," and later said that members of the committee "look forward to further open sessions."

The discussion may not have pushed the conversation very far forward, as the intelligence leaders' replies closely echoed what we've been hearing from the NSA for months now. But that the committee is beginning to open up such hearings could be a much bigger deal. It should help to keep the public better informed and ensure that intelligence officials are in fact being questioned about these programs.

According to the BBC, former GCHQ head Sir David Ormand also spoke earlier today in a separate interview, defending the agency's close relationship with the NSA: "We have the brains. They have the money," he reportedly said. "It's a collaboration that's worked very well."