I think it is well also for the man in the street to realize that there is no power on earth that can protect him from being bombed, whatever people may tell him. The bomber will always get through, and it is very easy to understand that if you realize the area of space. Take any large town you like on this island or on the Continent within reach of an aerodrome. For the defence of that town and its suburbs you have to split up the air into sectors for defence. Calculate that the bombing aeroplanes will be at least 20,000 feet high in the air, and perhaps higher, and it is a matter of mathematical calculation that you will have sectors of from 10 to hundreds of cubic miles. —Stanley Baldwin, A Fear for the Future
