The camp consists of three compounds, each a mile or two apart, and when travelling between any two you must be escorted by a truckload of Kenyan soldiers, just in case. The camp has become essentially a city in the desert, with schools and markets and permanent habitations. It has been there so long now that a generation of children has grown to adulthood without knowing any life other than being behind razor wire and heavy iron gates, and with a sense that all the world beyond this snug perimeter offers nothing but danger or indifference.