FROM a ragtag band of fighters conducting sporadic raids and bombings from its hideouts, Nigerias Boko Haram is fast evolving into a force able to take and hold territory. In attacks on September 1st its jihadist militants overran Bama, the second-largest town in Borno state.
Armed with rocket-launchers and armoured vehicles stolen from the demoralised Nigerian army, Boko Haram (its name translates loosely as Western education is forbidden) has moved beyond its established lairs in the Sambisa forest and the Mandara Mountains. In recent weeks it has taken several towns close to the Cameroonian border, among them Gwoza, Gamboru Ngala and Banki. (see map).