This is undoubtedly a bee fly, but which one I have no idea. My European insect book doesn't show a white haired bee fly and the only images I could find on the Internet (on a quick search) were native American species. Also, the most common European bee fly, Bombylius major, has a different wing pattern and colouring.
I see someone has identified this as Bombylius incanus. This might be right, but it is not native to Europe according to wikipedia
(which as always must be used with some caution). However, I can't find a website that suggests anything to teh contrary. So this might be a visitor.
Someone asked for an ID on a white bee fly (from Spain I think) on diptera.info but got no replies. See -