What happens after the visitors have gone is extraordinary. It’s the biggest spring clean in the world and it requires not just elbow grease, but in-depth knowledge about the conservation of precious artefacts
With unique access to Petworth House, in Sussex - one of the National Trust’s gems – art historian Andrew Graham Dixon joins the conservation team who toil through the winter, revealing the secret life of one of our greatest country houses, seen from behind the velvet rope.