Mass London Exodus By UNITED PRESS LONDON, Sept. 1 The army of the helpless also mobilized today. The vanguard of 3,000,000 persons the young, the lame, the halt and the blind streamed out of Britains cities in one of the great mass movements of history, a flight to destinations unknown. Children led the way out of the target areas of the cities, areas that would be the first to feel the impact of death from the skies if war comes. They were told that they were going on a holiday, but mothers dont stand weeping along train tracks as they did today if a boy or a girl is simply going to the country for a holiday. The children knew that this was another kind of holiday a holiday from death and broken bones and smashed faces. Peter Selmes, 8, wearing a blue coat and dark brown trousers with a patch on the seat, spoke for all of them old enough to speak, when he said with a wise look in his eye: I know where Im going, but Im coming back soon. And Ian Channel, 10, also knew that this was no autumn pleasure trip to green fields and clean, running brooks. My mother told me that I was going to the country to look for apples, he said, but I know better. My brother is in the navy and he said the Germans were going to bomb London. Children from 4 to 16 years of age came first. They were pouring out of schools, homes and hospitals. Most of them marched in precise double file, but out of Charing Cross hospital came a battalion that couldnt march. They were on stretchers. They had toys tied to their stretchers and most of the young ones clasped teddy bears or pandas. The enormity of the job was indicated by the fact that 700,000 school children must be removed from London alone. All weekend it will go on, and authorities hone that enemy planes would not darken the London skies before Monday. It will take that long to get the helpless out of deaths way.