@Edent iNaturalist says that this is Spanish Fly (an Oil or Blister beetle). Historically, were ground up as an aphrodisiac (plot point in Patrick O'Brian's Treason's Harbour). There are only three records for this species on #iNaturalist for the UK🇬🇧, so it would be nice if you could add this one (with suitable care over location privacy).

#SpanishFly #Melodidae #Lytta #Coleoptera #IridescentBeetle