Abstract: UV sensing apparatus comprises a substantially light-proof housing (1), an aperture (1a) formed in the housing, a filter (2) positioned within the housing at the internal mouth of the aperture, a fluorescent member (3) positioned within the housing on that side of the filter remote from that adjacent to the aperture, and a light sensor (4) positioned within the housing to receive light emitted by the fluorescent member. The filter (2) is such that it substantially removes visible light, the fluorescent member (3) is such as to fluoresce when subjected to UV radiation, and the light sensor (4) is positioned so that substantially none of any electromagnetic radiation entering the housing (1) via the aperture (1a) impinges upon the light sensor.