Sionaidh Douglas-Scott, Anniversary Chair in Law at Queen Mary University of London, has published a prescient book on the ways in which Brexit has had an impact on both the uncodified nature of the British Constitution and the union of the United Kingdom. Many books since 2016 have been published on the subject from Vernon Bogdanor’ Beyond Brexit: Towards a British Constitution (2019) to Andrew Blick and Peter Hennessy’s The Bonfire of the Decencies: Repairing and Restoring the British Constitution (2022), but Douglas-Scott’s originality is in the way in which she has decided to look into the matter. Her methodology divides her book into two main parts, focusing on five historical case studies and five main themes related to the meaning of constitutional power. The result is to show that a new constitutional settlement is needed and that without it, the way Brexit has exposed the cracks in the system might very well break the union. Whether or not the reader agrees with the conclusion is not the point; what is, however, is the very spirited ability to weave British constitutional history, politics and legal reasoning, making it a good read for a book of such a length (523 pages), even if, unfortunately, the very methodology leads to several repetitions. The other important aspect of this book is the step-by-step approach and the ability displayed to never lose the reader in dry academic legal debates.

From the outset, the introduction denounces the historical version of the British Constitution, the main culprits being Dicey and, to a lesser extent, his Victorian sidekick, Bagehot. Both straightjacketed the constitutional narrative in cementing the idea of parliamentary sovereignty and in focusing on the role of the Cabinet, respectively. Of course, this version of the Constitution has already been denounced precisely for its outdated nature over the last twenty years. Yet, the author makes clear that carrying on with the fallacy of parliamentary sovereignty damages the country in the quagmire it faces after Brexit.

In the first part, dealing with five major legal case studies, Douglas-Scott looks into major historical upheavals that happened in the constitutional history of the Kingdom. The first three cases—Scotland, Ireland, and the American colonies—set the tone for the various interpretations of the idea of parliamentary sovereignty. The legal status of the unions which were decided with either Ireland or Scotland, or with the American colonies, were never as clear-cut as expected, leading to conflicts of interpretation. The problem is always about the Anglo-British domination over other nations and how Dicey’s Victorian parliamentary sovereignty, seen as a pure construct, can easily be challenged by the reality on the ground in previous centuries. The reality is much more about how popular sovereignty (whether in its Republican understanding in the American colonies or derived from different traditions in Scotland and Ireland) challenges parliamentary sovereignty as an absolute or inalienable concept (138). The other idea expounded—along with Coke—is that “natural law and reason” can also be part of the sources of the common law (176). So, the question was always about who had “ultimate constitutional authority” (181), which was also the very same question at the time of Brexit.

The fourth case study—on the British Empire/Commonwealth—naturally follows to point out the lack of rationale in the constitutional links organized between the mother country and the colonies (or their various types of status). The lack of one single Imperial Constitution meant that pragmatism ruled the way. Yet accommodating plural and often incoherent types of sovereignty allowed the use of brutal means to force the countries of the Empire to submit. The last case study on the relationship between the UK and the EU delves into how British exceptionalism ruled the day at the time of the Brexit debates and how the tension about Dicey’s sovereignty of parliament was stretched to the limit by joining the European Economic Community in 1973. The chaotic political period post-2016 ends up being the result of incoherent and badly defined understandings of the scope of national, parliamentary, and popular sovereignty.

The second part of the book, through five main themes, is very different, looking into world constitutional history in a much deeper way than the title of the book implies. There are forays into global legal questions related to the ideas of sovereignty but also to disunions, federalism, referendums, or human rights. Here, the meaning of sovereignty is tackled to elucidate what Brexiteers were trying to defend with the “Take Back Control” narrative. A plea is made in favor of clarification of political terms—devoid of simplistic meanings—pointing out how democratic life cannot be reduced to outdated historical beliefs or populist slogans. Douglas-Scott believes that if “fear” (343) is what is keeping the union together, it might be useful to start thinking clearly about what the break-up of the UK union would mean instead of sleepwalking into it. Unsurprisingly, the conclusion defends a codified constitutional document which would correspond to what the UK has become.

The book suffers from repetitions (especially in the second part), but this is probably to allow chapters to be read separately. There are some surprising omissions, such as the Quit India movement, which could have benefited from a paragraph (208), along with how Diceyan parliamentary sovereignty relies on the deference of the people to the uncodified constitution. In this sense, Bagehot would have been very useful to explain how obedience is not only based on trust but also on a type of political deference (both rational and irrational), which did not die away fully in the twentieth century and which resurfaced at the time of Brexit. This is certainly the aspect missing in the book based on the constitutional value of political imagination.

There are very few slips except when Locke's Second Treatise on Civil Government is said to have been published in 1690 in “justification of the Glorious Revolution” (149). Yet, as Peter Laslett’s 1960 Cambridge edition made clear, Locke's book was written before 1688, modifying the understanding one can have of this seminal work.

Apart from the above-mentioned, this book is both insightful and a monumental feat in terms of the number of historico-constitutional details summarized and analyzed. The vision it gives of Brexit is one that cannot be detached from the long constitutional history of “union and disunion” of the Kingdom. Undoubtedly, Douglas-Scott has written a work which will inspire students and researchers to try and blend history and constitutional global history in the same rich and seamlessly effortless way, but they will find it very hard to match.