Supporters of the old British empire assumed it would last for ever. They were wrong. It disappeared because the mood of the age was against it, abetted by inept colonial administrators. Only in the white commonwealth was retreat dusted with some dignity. Meanwhile Britain’s earlier empire, that of the English over the so-called Celtic half of the British Isles, has also been crumbling. Most of Ireland is gone. Salmond’s white paper is a blueprint for dismantling the rest.