A red-legged robber fly, Dioctria rufipes (family Asilidae, order Diptera) feeding on a small hemipteran bug. When I got too close with my camera, it flew off to another leaf, carrying the bug with it. Initially, I was surprised that a small fly could bear such a burden through the air, but then I realised that these flies have to be able to carry their prey at least a short distance because they catch them on the wing. However, it only flew a short distance each time I disturbed it, and I was able to get close to it again and again, and take more photos.
Photo taken in Reading University grounds, Reading, UK, on 2009-06-14.