Do not be fooled by those dark, drab coloured fore-wings, they are for camouflage purposes whilst this nocturnal moths rests during the day. Once opened up they reveal the most lovely yellow, almost golden, secondary wings underneath. It is one of several species with drab fore-wings and brightly coloured under-wings and of those several species this is one of the largest hence its common name, the large yellow underwing (Noctua pronuba).
My photograph is of one with very dark wings but it is actually a very variable species and those wings can be any shade of brown from this dark colour through to a light buff colour. One can find a complete range in the same catch in the moth trap and you would, at first, think they were separate species. Whilst the fore-wings vary in colour the yellow under-wings do not.
This is a very common species found across the whole country from May right through until November. It seems to have no real preference for habitat or food plant and it has several broods a year and it is thought that numbers in the south are increased even further by immigrants from across the channel.