Hendrefoilan House, south Wales (1853, by William B Colling, Grade II*) Commissioned by Welsh industrialist and MP Lewis Llewelyn Dillwyn, Hendrefoilan House was built on the site of a medieval farmhouse that had the same name. It was taken over by Swansea University in the 1960s and was used for accommodation and teaching. Now water floods down the outside walls, leading to damp inside, and lead thefts have begun to occur

Photograph: Debra John