United States President Donald Trump stands poised to declare victory over the so-called Islamic State. US-backed forces have converged on the group's last holdout in the Syrian village of Baghuz. When these five sq km are retaken, the brutal insurgents who once ruled over eight million people in an area as large as Britain will no longer command any territory. Yet this is by no means a "mission accomplished" moment. It can only mark the beginning of a different, more shadowy and insidious war. ISIS will have to be engaged continuously and relentlessly.

Even with no territory, the ISIS flag will continue to fly in cyberspace. Its pernicious ideology remains potent and contagious. Millions across the globe, in the developing and developed worlds alike, are receptive to its message. Its tribe of imitators and sympathisers continues to attempt attacks. The Pentagon's own assessment says the terrorist group is intent on reconstituting itself and could retake land in a matter of six to 12 months should the US military withdraw from Syria. Mr Trump's director of national intelligence Dan Coats testified before Congress last month that this loosely-knit organisation has returned to its guerrilla warfare roots and continues to plot attacks. General Joseph Votel, head of the US military's Central Command, has said that ISIS still has "leaders, fighters, facilitators, resources and the profane ideology that fuels their efforts".