Abstract: A disinfection apparatus, typically an autonomous or semi-autonomous robot which has a germicidal light source, a controller for controlling emission of germicidal light from the germicidal light source and a moveable support to which the germicidal light source is attached which is moveable across a surface. The apparatus may also have a detector which detects the presence of an object in the vicinity of the apparatus wherein the controller controls the direction of germicidal light from the light source in response to the detection of one or more said object.