MI5 Boss Calls For New Powers to Tackle 'Greatest Threat' of His Career

The head of Britain's internal counter-intelligence service MI5, has warned that ISIS and other extremist groups "continue to aspire to mass casualty attacks against the U.K." and that an increasing proportion of their communication online and via encrypted channels is out of reach of Britain's security services.

"All of this means the threat we are facing today is on a scale and at a tempo that I have not seen before in my career," Andrew Parker said in his keynote speech made at a lord mayor's event in London on Wednesday night.

Next week, the U.K. parliament is due to debate a bill that would grant British security services extended surveillance powers. Parker said modern channels of communication have invigorated groups seeking to attack the U.K. and that MI5 needed new powers in order to keep up with developments in modern technology.

"As I have said before, we do not, and could not, go browsing at will through the lives of innocent people," he said as part of his lecture titled A Modern MI5. "But today the conversations of our adversaries are happening on a bewildering array of devices and digital platforms, often provided by companies based overseas. And an increasing proportion of such communications are now beyond our reach—in particular with the growing prevalence of sophisticated encryption."

Parker also warned of the "three-dimensional threat" that ISIS pose—at home, overseas and online. "We are seeing plots against the U.K. directed by terrorists in Syria; enabled through contacts with terrorists in Syria; and inspired online by Isil's [ISIS] sophisticated exploitation of technology."

Parker said MI5 must evolve its activities in order to combat modern threats, and emphasized that the agency's ability to intercept communications has "been a key component in MI5's toolbox throughout our history."

The MI5 boss said he imagined the forthcoming defence review would garner more public interest than previous debates on similar matters. "But I hope that the public debate will be a mature one, " he added. "Informed by the three independent reviews, and not characterized by ill-informed accusations of 'mass surveillance', or other such lazy two-worded tags."