Thin films of chemically vapour deposited diamond have been used to fabricate photoconductive and photodiode structures for the detection of UV light. On free standing (80 pm thick) material, a planar interdigitated design with 20 pm electrode spacing is found to offer greater than five orders of magnitude in wavelength discrimination between deep UV and visible light, with dark currents <0.1 nA, when a methane-air gas treatment is used. On silicon supported (6 Frn thick) films, a planar photodiode utilising gold Schottky and Ti-Ag-Au ohmic contacts, also offers a sharp cutoff in photoresponse in the deep UV with no measurable dark current; photoconductive devices fabricated on this material do not show useful levels of performance.