Dr Johnson is supposed to have said of Milton’s Paradise Lost that all admire but few have wished it longer. The BBC’s three hour history of Istanbul aka Constantinople aka Byzantium on the other hand really could have done with being a good deal longer. How is anybody supposed to tell the story of a place with such an event filled history in so little time? Brevity and compression are great things in many ways, but you can take them too far. Quite apart from having to leave so much out, you also just don’t get the sense of depth you need to appreciate such a large subject.