The figure represents one third of their estimated open market value, but why is it so important to save the works for the nation, and how difficult will it be to raise the cash? National Gallery of Scotland director John Leighton: “I think it would be hard to exaggerate the misfortune it would be. In our terms it would be like the Mona Lisa being taking out of the Louvre, or the Uffizi gallery in Florence losing its Botticellis,”