Former president tells Scottish audience there needs to be accountability and transparency when surveillance is used

Former US president Bill Clinton has said Americans need to be "on guard for abuses" of power by the US government through its secret interception of emails and phone calls in the name of national security.

In a question and answer session at a business dinner in Edinburgh, Clinton said the use of secret surveillance by the National Security Agency (NSA) to intercept communications by foreign terrorists was justified.

And the US system also required a warrant from intelligence courts, backed up by sufficient evidence, for any surveillance activities against people within the US.

But he said it was crucial there was accountability and transparency in the use of surveillance and interceptions by agencies such as the NSA – an area which he said was "blurry, grey and made people uncomfortable".

"There's no question that it's subject to abuse if people lie to the courts or if the wrong people get hold of the information and try to use it to embarrass people, but that has pretty much always been the case. It's just we're so aware of it now," Clinton told his audience at the Scottish Business Awards.

"I believe the most important thing is that we have accountability. But I will say this – freedom and security are not incompatible; they're mutually reinforcing.

"I think you're more secure if you have more freedom. Therefore I think we should be on guard for abuses of the use of technology by our government."

He said his own experience from two terms as US president was that governments had a duty to use that technology against threats and opponents, who planned to kill civilians.

"I can tell you from when I served that we did – and far more attacks were stopped than were pulled off," he said.

New information technology, such as smartphones, had "dramatically changed" and shrunk the parameters of personal privacy but he warned that state security operations of this kind needed to be very closely monitored.

"So this is one of those areas, which in my opinion will always be blurry, grey and make people uncomfortable, and we wish we didn't even have to talk about it or deal with it. But freedom and security are not necessarily mutually exclusive.

"You can destroy freedom with false claims that you have to do it to make everybody secure, but usually when somebody's doing it, they don't give a rip about security, they're just trying to get more power.

"And so the key here is accountability, transparency and protection against use of information, inadvertently found, for other purposes."