Photo taken on 22/07/18 at Kensworth, Beds.
This is a fairly common moth in the south of the UK, less so further north and in Ireland. It takes its name from the blood-red line across its wings, but it also has a noticeable pink edge to the wings. It flies between May and mid-September (or to November in the South)
Photo taken on 21/08/10 at Kensworth, Beds. This moth was a highlight from my first night's moth trapping!