I would have preferred he had alighted over the lake, but this was the only one I saw actually land! I've done a Google search I think it's a Erythemis Simplicicollis or an Easstern Pond Hawk but I'm sure Louise will know!! (No pressure @roachling !!)
For a view of the lake pop over to TheDarkroom where this week we're splashing about with water. Join in with the tag darkroom-water
the eastern pond hawk isn't a UK species so it's not that. I can't see the colours / markings clearly enough at this angle but it's a male (by the colour) and either a broad bodied chaser or a black tailed skimmer I'd say. I can't see if there are dark patches at the base of the wings well enough here but I'd lean towards the skimmer over the chaser.