This flew just after I took the picture with the camera in my other hand. They often turn up at the same times as Painted Lady butterflies, their first generations in summer having migrated together from southern Europe and North Africa.
These are day-flying and hover around flowers as they feed on nectar.
It gets its name from the small y shape on each wing. The specialists recognise different species of Silver-Y.
Haven’t seen or heard of any Painted Ladies this year, but there were seven Peacocks together on the Buddleia where I found this moth at Barkisland.