MI6 chief Alex Younger said the threat of the Islamic State would last a lifetime, posing a persistent and enduring threat to the world. He made the comments as MI6 plans to recruit 1000 additional spies and France announces the deployment of 40,000 extra troops and the creation of 8000 isolation cells by 2018.

"I would like to be optimistic about this but we have got quite long experience of this phenomena now and I see it very much as the flip side to some very deep-seated global trends, not least of all globalisation, the reduction of barriers between us,” Younger said recently.

"It is fuelled by a deepening sectarian divide in the Middle East and there are some deep social, economic and demographic drivers to the phenomenon that we know as terrorism."

Digital technology was an "existential threat and a golden opportunity", he said.

"This is a famously important issue and one that will dictate our future success,” Younger said. "Our opponents, who are unconstrained by conditions of lawfulness or proportionality, can use these capabilities to gain increasing visibility of our activities which means that we have to completely change the way that we do things."

Richard Lizurey, the director of the French national gendarmerie army corps

Meanwhile France plans to have more than 40,000 reserve combat troops on call for internal defense by 2018, and will spend more than €1.1 billion creating an additional 10,000 prison places, 80 per cent of which will be isolation cells for dangerous prisoners and terrorists.

“Fighting terrorism has become our number one priority,” said Richard Lizurey, the director of the French national gendarmerie army corps. “Around 2,300 additional soldiers were recruited in the past 10 months alone, this is the first time we have hired so many people in such a short amount of time.”

Lizurey said in addition to the 40,000 extra troops, the gendarmie would pay for 3000 more vehicles, and stock up on heavy weapons and bullet-proof vests. ♦