The British Empire stole a lot of stuff. Much of it still sits in museums, galleries and private collections today, accompanied by calm labels and polite plaques. The reality, however, is far messier. The British Museum alone holds eight million objects, many taken in ways that were anything but legitimate. When award-winning journalist and author Marc Fennell encounters one such item—a mechanical tiger that mauls a British soldier when you turn the handle—he asks the obvio...