These two books are part of a recognisable genre: a shelf of earlier examples looms over me as I write. They have been published at regular intervals over the past fifty or so years, at moments perceived to be crises of the British state: the Hamilton by-election of 1967, the devolution debates of the mid-1970s, the aftermath of the general election of 1997, the establishment of the Scottish Parliament and, most recently, the Scottish independence referendum of September 2014. Indeed, going further back into the constitutional debates about the nature of the United Kingdom, we could note the outpourings during the crises of Irish Home Rule from 1886 to 1922. Further back still were the pamphlet wars occasioned by the unions of 1707 and 1801. Some publications are still read, such as the works of the Victorian jurist A V Dicey and the books of Tom Nairn nearer our own time. Others have slipped from view; who, other than this reviewer, is familiar with Ireland versus England by Donald Horne Macfarlane? An MP who represented seats in Scotland and Ireland during a parliamentary career in the 1880s and 1890s, Macfarlane had concerns about the problems of governing the UK that speak to us today.

What these books have in common is a sense of the precariousness of the UK. This has to be set against the enduring nature of the Anglo-Scottish union. What might make this present moment different from previous ones is the combination of pressure from Scottish nationalism with the effects of