You have one of our two red-eyed (Erythromma) species, either a Red-eyed Damselfly (Erythromma najas) or a Small Red-eyed Damselfly (Erythromma viridulum).
There is a commonly held misconception that the presence of a separated dot in front of the spur on the thorax side can distinguish but this is not reliable. [See Redeyes: Myth Buster] We have to be a little more careful.
First of all, is it male or female – is there a tail light or not?
A tail light – male Erythromma
No tail light – female Erythromma