Common Blue Damselfly

Taken at Brochkholes Nature Reserve in Preston. I took this with the zoom lens and cropped but now I know where I can find these damselflies, I will go back with the macro lens and some proper equipment.

I don't know why it has got the letter 'L' on the end of its tail. It looks as though it has been tagged - I can't see the staff at Brockholes tagging every damselfly though - Can you? :-)