A stair nosing for use on stairs with composite tread composed of a stair tread and a supplementary tread of e.g. LVT, which is an elongate profile member having a back facing for abutting a front surface of the composite tread, an opposing front facing and a profile tread surface and a first fixing to fix to the nose surface of the stair tread is able be fitted securely to a stair with a bull nose without the need to adapt or cut the bull nose. The stair nosing is capable of bending in order to fit to curved stairs thereby enabling supplementary tread or covering to be applied to a curved stair without squaring off or reforming curved stairs.