This is was one I found (very well hidden) in Longford Park - Manchester, on a rather sunny day. The Buxus sempervirens is an evergreen tree, or large shrub as is the one I have photographed below. The shrub is small and very dense, and has a distinctively glossy distribution of leaves which are only around 2.5cm in length.
Information from Collins Complete Guide to British Trees
Information from Collins Complete Guide to British Trees