Scarcely a day passes without the Islamist gunmen of Boko Haram carrying out an atrocity in northern Nigeria. Last Sunday, they were bold enough to attack the city of Maiduguri and, for a few hours, fight for control of the airport.With a population of 1.2 million people, Maiduguri is the capital of Borno state and the headquarters of the Nigerian army’s 7th Division. The fact that Boko Haram possessed the strength to strike this particular target tells you all you need to know about its confidence.It also drives home the most important development of the past few months, namely that Boko Haram has leapt from being a rebel movement capable only of mounting hit-and-run attacks to one that actually controls territory.At the same time as the raid on Maiduguri, another Boko Haram force