I just received this message from Will Wagstaff on the Isles of Scilly
A quick update to say that your butterfly is a different individual to the one we saw last week. I sent the photo to one of our local experts who compared it to our one and there are significant differences between the two. Also there was one in Cornwall on roughly the date you had your one on St Agnes so it may well be that it is then that they arrived in theUK.
It looks like there have been a few sightings – this is, indeed, a rare occasion. All this strange weather we have been having. (Photo coming this evening) See previous post