British officials are engaged in behind the scenes reviews designed to address the threat from hundreds of ISIL fighters trying to return to the country from front lines in Syria and Iraq.
Security sources believe the number of potential returnees remains more than double the 150 suspects known to have been stripped of citizenship for terror activity abroad in recent years. Work is under way in the main administrative buildings in Whitehall, London, to target ISIL veterans.
Sources said that lengthening official watch lists of British citizens and residents recruited to ISIL ranks had become a priority for the security services. Newspaper reports have revealed that 40 of the 150 people stripped of British nationality since 2011 — under so-called deprivation orders — were sanctioned in the past year.
There are believed to be at least 350 still active in the region but primed to come back. Experts believe another 400 Britons have already returned and while some are under close surveillance, others have slipped through the net.
Addressing the figures, Ben Wallace, the Home Office minister for security, hinted that a wide range of measures were being rolled out as ISIL loses territory. “We are using a range of tolls to disrupt and diminish that threat.”
Hannah Stuart, a security expert at the Policy Exchange think tank, told The National that the government's extremism strategy was under careful scrutiny in the wake of multiple terror attacks in London and Manchester in the early summer. "Government has been very aware work needs to be done on a number of levels, not just counter-radicalisation efforts but also exclusion orders and other measures," she said. "Officials are looking at some of the programmes needing a harder edge, the impact of police cuts, issues of rules of engagement with communities and operations of anti-terror police."
Not all those displaced from Syria and Iraq are necessarily targeting a return to Britain. Matteo Toaldo, a researcher at the European Council on Foreign Affairs in London, said Libya remained a plan B destination for extremists fighting with ISIL and others.
“The European intelligence services, starting with MI5 and MI6, now have lists focused on secondary territorial movement,” he said. “Parts of Libya are seen as safe havens by foreign fighters who want to continue the battle.”
The loss of Mosul and the inexorable crumbling of Raqqa's defences has seen a shift in ISIL’s own communications with its followers, particularly foreign recruits.
Charlie Winter, a researcher at the International Centre for the Study of Radicalisation and Political Violence, detected a decisive change to advising its loyalists to mount attacks in their homelands or places of residence earlier this year. The group no longer sold itself as an emerging paradise.
“In early 2017, the Islamic State produced 74 per cent less utopia-themed propaganda, and 100 per cent more warfare-themed propaganda, than it did in the summer of 2015,” Mr Winter said. “As its territorial clout, leadership, and manpower depleted over the course of 2016 and early 2017, the group was forced to recalibrate the strategic parameters of its propaganda narrative. In so doing, it reverted to salafi-jihadist type, coming to rely more than ever before on military-themed media than governance propaganda.”
According to the Washington-based Institute for the Study of War, ISIL has expanded globally as its territory has shrunk. The group's "global attack network is now more robust, dispersed, and resilient than ever”, it concluded in a recent report.
Leading European countries are struggling to hit on a model for handling the rise of extremism.
Emmanuel Macron’s government has announced plans to shut its only residential counter-extremism centre in Pontourny, western France, which opened in September 2016 to convince 18 to 30-year-olds to change their views. With rooms for 25 people, it never held more than nine at any one time.
"The experiment of this centre, which operates on a voluntary basis, has shown its limitations. The government has therefore decided to end the experiment," interior minister Gerard Collomb said.
Meanwhile the German newspaper Bild has defied tough new mobile phone and internet laws to demonstrate how easily ISIL can radicalise residents in the country. A reporter made contact with two English-speaking handlers who told him to destroy his existing SIM card, pick up a temporary replacement and communicate by the secure messaging app Wickr. The message he received was direct incitement. "Go into a hospital, find the seriously ill and slaughter them," wrote the Syria-based contact. "Don't plan too much, hit out quickly, the more time you allow yourself the more mistakes can happen."
In the race to keep ISIL operatives out of Britain, there is one under-used power that could come to the fore, sources said. Temporary exclusion orders allow the authorities to ban Britons from entering their own country unless they agree to join a deradicalisation programme or co-operate with a surveillance regime. “I think we will see a series of announcements in the autumn,” Ms Stuart said.