Public Rights of Way were first given their definitive map numbers during the original survey in 1950. Each borough, urban district and parish were asked to mark on the maps relevant to their area all paths they considered public, numbering them as they were entered. On further investigation, some of these were paths were eliminated from the final 1952 definitive map as not public thus creating gaps in the numbering sequence; paths that have become extinct since 1952 have also been removed.