The Orange-tip butterfly or Anthocharis cardamines. So well camouflaged against the nettles; I was very fortunate to be able to spot him yesterday. UK Butterflies.co.uk state that the male underside should have orange on the tips; I know this is a male because I watched him fluttering about before he alighted on the nettle, but he doesn’t have any trace of orange on the underside. Perhaps he was a young one. They inhabit hedgerows and feed on plants like Lady’s Smock. The orange tips are supposed to warn predators that they are inedible due to the essence of mustard which originates from their diet of cresses such as the Lady’s Smock.
I love butterflies. They are very tolerant of nuisances like me who thrust camera lenses at them.