Portable sign to safeguard school children when crossing the roads . Plan to save lives . In an effort to save the lives of a thousand children killed every year on Britain ' s roads , the Minister of Transport , Mr Leslie Hore Belisha has recommended that all children be supplied with a portable sign as a warning to traffic . The device shows the word ' Stop ' in large red letters with ' Children Crossing ' on a white background . the signs are to be used when school children are crossing the road between school hours . Pupils at St Micheal ' s School , London Fields , are already using the sign suggested by the Minister of Transport . Photo shows , children of St Micheals School , London Fields , crossing the road under the protection of the portable sign . 24 April 1936