Up until last year, Linnaemya picta had only been found in continental Europe but not in Britain. Then, in 2010, it was found first in Kent and later in Suffolk and Cambridgeshire. If my photos are L. picta it could mean that this species has now spread westward to the Thames valley. For more details of the discussion of these photos see here. For more details on how to identify L.picta see here.
Photos taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2011-09-21.