text: why do we have british summer time? it is in britain we change the time one hour forward? it goes back to the war effort and the conservation of energy. most countries choose to have a "daylight savings time" (as we call it here in the states). since people alter their schedules so that the work is done while the sun is up (an hour's difference), less energy is used. this was initiated during, at least in the states, during the war.