It's actually known as the Figure-of-Eighty, which makes sense if you look at its left forewing instead.
The markings are a particular distinct form of the kidney-shaped pattern familiar in many UK moths, sometimes prominent, mostly less so. With this species, the figures are always clear and rather beautifully drawn. There is also a Figure-of-Eight moth, a burlier fellow with cruder numbering, but it flies only in the Autumn.
One of these days, I may get the darker type of the Figure-of-Eighty, known as form fusca and first recorded in the 1940s. It is believed to be an immigrant from the Continent, a phenomenon as frequent in the moth world as in the current human one. Like most human migrants, these arrivals in the UK prosper here. By chance, another one of them came to see me at the weekend: the Dark Swordgrass preparing for take-off below. It has been hugely successful, reaching as far north as the Shetland Isles.This moth is usually sound asleep with its wings tightly-folded, so it's refreshing to see it full-on.