I first noticed this when a gangly yellow beetle flew across my field of view while I was trying to photograph another insect. Michael Chinery's Complete British Insects identifies it as Strangalia maculata, but two other synonyms, Leptura maculata and Rutpela maculata, seem to be used with equal frequency out on the web. I am not sure which is the currently recommended name. Anyway, it is a longhorn beetle, family Cerambycidae, order Coleoptera.
Photo taken in Reading University grounds, Reading, UK, on 2009-06-19.