Rare in marshes and on river-banks in the Norfolk Broads and in marshes near the sea in Suffolk; recently also recorded from Co. Durham (MBGBI Vol 3), a priority species under the UK Biodiversity Action Plan. Unlikely to be recorded in Hampshire or on the Isle of Wight. Wingspan 12-13.5 mm. Larva feeds within seedpods of Water Dock, living within a movable case.