4001=GEOGCS["Unknown datum based upon the Airy 1830 ellipsoid (deprecated)",DATUM["Not_specified_based_on_Airy_1830_ellipsoid",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],AUTHORITY["EPSG","6001"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4001"]]