You can see why it is a pleasure to welcome it. The iridescence on its wings is distinctive among UK moths with a spectrum which seems fleetingly to include all the colours of the rainbow as you study it from different angles. For classification reasons about which I am hazy, the moth is a micro although far larger than most of the others and indeed than many macros, including the one next to it (some sort of Carpet?) in the picture below.
It also has a fascinating caterpillar which is one of very few creatures in the world to use rolling as a means of locomotion or to be more precise escape. I can't show you a picture for copyright reasons but there's an extremely good one on the Photoscience library here. Here also is a scientific description culled from another fascinating website called AskNature which catalogues natural phenomena which may be useful to engineers and inventors:
The mother-of-pearl caterpillar, however, can step on the accelerator. If it meets a predator, it anchors its rear to the ground, recoils rapidly, and then rolls away backward like a bright-green tire. Mouth to tail, it completes around half a dozen revolutions during its escape. By turning into a wheel, the caterpillar moves some 40 times faster than its normal walking pace. (Downer 2002:22)
These are common moths whose caterpillars make a nest in rolled-up nettle leaves - also a familiar sight - so I will be out next breeding season with my camera.
Update: the sky over the M1 in Derbyshire last night, on our way back from Oxfordshire, reminded me of the Mother of Pearl. I hope the comparison survives a photo taken through the window as Penny batted along at 70mph.