This damselfly is one that I would consider to be localised and uncommon in my part of the country. I have only recently encountered a small pocket on a Kennet backwater.
They may be seen in flight from late May / early June, through to mid August. They are best seen in July when fully mature having attained their full colouration.
In relation to the male, the Variable Damselfly can only really be confused with the Azure Damselfly. They are similar in stature but the Variable is much darker, with more extensive black body markings. The wine glass mark on segment two is much larger than in the Azure Damselfly and has a stem at its base. Also the black tail markings on the abdomen are species unique.
The thoracic stripes on the Variable are broken across their length and resemble an exclamation mark. However it must be said that these can vary in size and shape, I wonder if that is how the species got its very apt name.
Females are far less common and are best identified whilst in the company of males of the species. When at the same site as the Azure, they can be indistinguishable.