The fight against Islamic State focuses on the swathe of territory it controls in Iraq and Syria. But the group has affiliates elsewhere, from Nigeria to Afghanistan. The most worrisome offshoot may be the three “provinces” in war-torn Libya, a burgeoning jihadist hub, where it controls a chunk of land and has some 3,000 fighters. IS has gained ground there amid the chaos of a civil war between rival governments, and their allied militias, in the east and west of the country. No state structures exist to counter its rise. Weapons, from rifles to rockets, abound. And the borders are porous. Europe, just across the Mediterranean Sea, is duly concerned. America has struck the group’s leadership, perhaps killing its boss earlier this month. The greater threat, though, is to neighbouring countries, which worry that Islamic militants, foreign or home-grown, will find inspiration, training and refuge in Libya.