The Common Blue Damselfly occurs throughout the UK and through most of Europe except the far north.
The blue male is shown above in a heart with the pale olive green female.
The blue male is bluer than the similar Azure Damselfly.
On the second segment of the abdomen, he has a distinctive roundish black blob linked to a black line.
Common Blue male, always blue.
Common Blue female - colour is variable.
There is a less common blue form of the female, shown coupled with the male above. She has less blue on her body than he does.
Some Common Blues (in several of the above photos) tend towards "whitelegged-ism" since they have a pale stripe
on the leg, but the blue male White-legged Damselfly looks very different with much more white on the legs and a different pattern on the back.