I don’t normally get to hear Start the Week – it’s when I’m working – so it was quite a treat to hear the episode this morning in which Andrew Marr dexterously juggled topics and ideas between Cynthia Saltzman at home in New York, Francesco da Mosto in Venice, and me sitting immediately opposite Andrew in Portland Place, as we roamed from Milan to Venice, to Paris and Berlin in search, first, of where Napoleon seized the greatest pictures to build up the collections of the Louvre and then, how the Louvre itself helped to inspire a great era of national, if not nationalist, museum-building:-