The ability of this moth to hover at a nectar plant makes it just about unmistakable; it surely lives up to its common name of the humming-bird hawk-moth (Macroglossum stellatarum). It can also fly backwards like a humming-bird and so is truly unique amongst moths. Although they do fly at night this is really a moth for warm summer days when it can often be seen in gardens, especially those gardens with red valerian flowers. In the wider countryside they have a distinct preference for flowers of the bedstraw family.
This is not a native British species, all specimens recorded here are immigrants from Europe and every summer some will be seen; it can be much more numerous in some years than others. There is some evidence to suggest that they are able to survive milder winters and are now being seen during on brighter days in January and February a well as during the summer. In fact, there are records for this species for every month of the year.
I have been trying to get a decent photograph of one for years, this is my best effort so far!