Head of U.K. surveillance agency: U.S. tech companies have become terrorists' “networks of choice”

Hannigan says that the members of the public “know” the Internet grew out of the values of Western democracy and insists that customers of the technology firms he criticizes would be “comfortable with a better, more sustainable relationship between the agencies and the technology companies.”

Hannigan called for a “new deal” between democratic governments and the technology companies in the area of protecting citizens.

“It should be a deal rooted in the democratic values we share. That means addressing some uncomfortable truths. Better to do it now than in the aftermath of greater violence.”

In the op-ed article, Hannigan says ISIS differs from its predecessors in the attention it pays to the security of its communications, presenting an even greater challenge to the security services.

He writes: “Terrorists have always found ways of hiding their operations. But today mobile technology and smartphones have increased the options available exponentially.

“Techniques for encrypting messages or making them anonymous which were once the preserve of the most sophisticated criminals or nation states now come as standard. These are supplemented by freely available programs and apps adding extra layers of security, many of them proudly advertising that they are ‘Snowden approved’. There is no doubt that young foreign fighters have learnt and benefited from the leaks of the past two years.”

Labor Party MP Tom Watson welcomed Hannigan’s contribution to the discussion of the issue of privacy and security, and said it helped to map out where we should draw the line on privacy and helps the same agencies “to rebuild their legitimacy post-Snowden.”

He added, however, that “I hope they do not confuse the use of public propaganda through social media by extremists with the use of the covert communications. It is illogical to say that because Isis use Twitter, all our metadata should be collected without warrant.”

The Financial Times reports that Hannigan’s comments come after the director of the FBI, James Comey, called for “a regulatory or legislative fix” for technology companies’ expanding use of encryption to protect user privacy.

Comey, reacting last month to Apple and Google introducing strong default encryption on their latest mobile operating systems, said “the post-Snowden pendulum has swung too far in one direction - in a direction of fear and mistrust.”

“Justice may be denied because of a locked phone or an encrypted hard drive,” said Comey. Without a compromise, “homicide cases could be stalled, suspects could walk free, and child exploitation victims might not be identified or recovered.”