the british had fought the [[somaliland campaign]] (1900–1920) against [[mohammed abdullah hassan]] and the [[dervish state]], to gain control over the territory. in 1910 the british garrison had been forced to retreat to the coast until the end of the first world war and only after four campaigns did somali resistance end in 1920, after three weeks of attacks by local troops, a [[king's african rifles]] (kar) battalion and the [[royal air force]] (raf). the colony had an area of about with a plain inland from the coast up to deep, ending at a mountain range an average of high.