How Are Private Art Collections “National Treasures”?

“Pictures, over the decades, have been earmarked by the government as ‘national treasures’, which are not to be given export licences. My republican gorge rises. How are Van Dycks, owned by the earls of Pembroke, part of anyone’s heritage (unless your name is Herbert, of course)? “We”, the nation, can see the pictures, at Wilton House for £12 a head (or, touchingly noblesse oblige, free on September 7 this year). But that doesn’t make them ours.”