From a few days back: one of several male Muscid flies that were sunning themselves on the trunk of a birch tree. I took the following specimen which Nikita Vikhrev at Diptera.info identified as Phaonia fuscata (Diptera: Muscidae).
It was about 8mm long, from head to tail. Named 'fuscata' presumably because of the two darkened ('fuscate') veins on each wing (though some other Muscid flies also have these darkened veins).
First photo taken in the Wilderness, Whiteknights Park, Reading University grounds, Reading, UK on 2012-04-11.