female DAINTY DAMSELFLY - note the long pale pterostigma; no spine on the 8th abdominal segment; faint spur on side of thorax; rocket shapes on abdominal segments with a faint tip; narrow antehumeral stripes compared to female Com. Blue and the pale legs. Not easy to see in the photo, but size compared to that of Common Blue is smaller with a different flight action also noted.
Blue-tailed Damselfly form rufescens
Emerald Damselfly.