I conceived this lecture in an attempt to stand back from the partisan hurly-burly surrounding the independence referendum. Instead it probes the nature of the British state from which nationalists want to separate (though not, it seems, entirely) and to which unionists want to cleave (though not, it seems, all that closely). If alignments in the current debate sometimes seem surprising and unpredictable, there are puzzles of an even deeper and more intractable kind on view when one puts the British constitution under the microscope.
The Anglo-British Interpretation
After all, the Union of 1707 which joined the Kingdoms of England and Scotland would appear to the naïve observer to be in some way constitutive of the British state which it created. Yet, if one turns to the writings of jurists and historians on the British constitution, one will often be hard pressed to find more than the occasional mention of the Union of 1707. To all intents and purposes the dominant Anglo-British tradition of constitutional interpretation – whose most influential exponent was A.V. Dicey - treats the British constitution as a mere continuation of the pre-1707 English constitution. According to Dicey the Act of Union with Scotland enjoyed no greater status in British constitutional law than the humble Dentists Act 1878, for there was no body of fundamental law entrenched at the base of the British constitution. Whatever laws parliament passed, he argued, were subject to repeal by subsequent parliaments.
The Scoto-British Interpretation
In recent decades, and under the inspiration of Lord Cooper’s celebrated obiter dicta in MacCormick v Lord Advocate 1953 SC,396, an alternative tradition of constitutional interpretation has emerged, which one might label as Scoto-British. This minority tradition - though its supporters are not necessarily a minority north of the border - takes the Union seriously as a central element in the British constitutional heritage. The most influential proponent of this line of thinking was the late Sir Neil MacCormick who modified Dicey’s doctrine of parliamentary supremacy to take account of the formative role of the Union in the very creation of the British state. In MacCormick’s succinct encapsulation of the British constitution, ‘Whatever the Queen in Parliament enacts, unless in derogation from the justiciable limits set by the Articles of Union, is law.’
The Scottish Nationalist Interpretation
MacCormick had, of course, been an SNP MEP and a senior figure in the Party, as well as holding the Regius Chair of Public Law at Edinburgh, and it is interesting to note that over the past century Scottish nationalist intellectuals have taken the Union seriously as a constitutional document, indeed much more seriously than unionists. In so far as a body of strict constructionist doctrine exists in the UK, it exists as a Scottish nationalist interpretation of the British constitution.
Popular sovereignty: 1320 and all that
However, departures from the norms of Anglo-British constitutional interpretation are not confined north of the border to the SNP. The Lib-Lab Claim of Right which provided some of the crucial ideological momentum towards the current devolution settlement was predicated on the notion that a distinctive Scottish constitutional tradition of popular sovereignty – quite different from the English tradition of parliamentary sovereignty - derived from the Declaration of Arbroath (1320), and was not extinguished at the Union, but lay dormant until revived in the late 1980s. This notion is based on some fairly shaky history, but regardless of its historical accuracy is now part of the language of constitutional discourse in twenty-first century Scotland. The future settlement of the British constitution will inevitably involve some friction between the supposed principles of 1320 and the 1688 principles which underpin the English Diceyan tradition.
The Euro-British Context
The British constitution is currently in a state of flux. While devolution and the Human Rights Act 1998 have provided an indirect challenge to Diceyan assumptions, the United Kingdom’s place in the European Union has led to a direct – if only semi-complete – assault on the old orthodoxies of parliamentary supremacy, non-entrenchment and the doctrine of implied repeal. The seven Factortame cases, not least R v Secretary of State ex parte Factortame Ltd. (No. 1)  2 AC 85, juxtaposed the contending supremacies of EU law and the UK parliament. The Merchant Shipping Act 1988, which introduced a licensing system to exclude Spanish owned or controlled fishing vessels from being registered as British , had not, it appeared, impliedly repealed the relevant portion of the European Communities Act 1972. Moreover, the decision in Thoburn v Sunderland City Council  QB 151, introduced the very un-Diceyan notion of a hierarchy of statutes, with constitutional statutes enjoying a greater degree of entrenchment, or at least protection from implied repeal, than mere ordinary statutes. No longer, it seemed, was the Act of Union the humble equal of the Dentists Act 1878. The Euro-British embrace had effected a subtle transformation in the nature of British constitutional understanding.
The West Lothian Question
Politicians and jurists continue to grapple with the constitutional anomalies associated with Union. The West Lothian Question continues to enjoy a high profile in British constitutional debate, and defies easy – or at least logical – solution. Rather, it serves as a reminder of how difficult it is to federalize the British union-state, where an English nation – which is unwilling itself to be federalized – comprises almost eight-five per cent of the UK population. Moreover, the West Lothian Question also brings into focus the multi-layered nature of the British constitution, and in particular the multiple legislatures – in terms of function and territorial remit - which seem, like Russian dolls, to inhabit the supposedly single space of the British parliament.
Kirk and State
Less obtrusively, but just as rich in insoluble constitutional difficulty, was the case of Percy v Church of Scotland Board of National Mission 2001 SC 757, 2006 SC (HL) 1, which involved an associate minister of the Church of Scotland, the Rev. Helen Percy, who was forced to demit office in the wake of her affair with a Kirk elder. Until the mid-twentieth century, certainly from the Patronage Act 1712 to the Church of Scotland Act 1921, the main long-term irritant in the Union was attributable to church-state relations, especially the tensions between a British state founded on the constitutional principle of parliamentary omnicompetence and an anti-Erastian Church of Scotland, which believed that the Kirk was not subordinate to the British state. Indeed, Scots Presbyterians took the view that the jurisdictions of the spiritual and temporal realms ran in parallel and that the Kirk’s autonomy enjoyed constitutional protection by way of the Act for Securing the Church of Scotland, which was an integral accompaniment of the Treaty of Union in 1707. After many decades of church-state wrangling, which included the Secessions of the mid eighteenth century, the Disruption of 1843 and the parliamentary repeal of lay patronage in 1874, the Church of Scotland Act 1921 appeared to confirm the Kirk’s understanding of its own separate sphere of legislation and jurisdiction in matters spiritual. In the Percy case, the late Lord Rodger on the Court of Session upheld the Kirk’s autonomy, but this ruling was, surprisingly perhaps, overturned in the House of Lords, and, notwithstanding the 1921 Act, Ms. Percy’s claim for unfair dismissal was, the Lords concluded on a four to one decision, justiciable in the civil courts.
A Convention of Non-recognition
Notwithstanding the common misconception that the UK has no constitution, there is a British constitution. It is, of course, not set down in any single document; nor is it entirely a matter of law, but is also composed of inherited prerogative powers and certain non-legal conventions. Not only does the Union complicate the core constitutional doctrine of parliamentary supremacy, but the decision of generations of jurists, historians and constitutional authorities to overlook the notionally foundational – or at least quasi-foundational – role of the Treaty of Union and the accompanying guarantees of Scottish ecclesiastical autonomy framed in 1706-7 amounts in itself to another kind of convention. There has been an unconscious convention that the historical facts of 1706-7 did not have any significant bearing on the ongoing domestic evolution of the English constitution, and could therefore be safely ignored: a convention, if you like, of non-recognition. Of course, generations of Anglo-British jurists had a very plausible excuse for ignoring what was latent in the constitution and had not been articulated in constitutional discourse. In the wake of Cooper, MacCormick and a host of other commentators on the ‘new British constitution’, there is now no such excuse. As God said to the newly deceased Scots sinner who on his arrival in Hell had pleaded, ‘But, Lord, I didna ken’: ‘Well, ye ken noo’.
Colin Kidd is Wardlaw Professor of Modern History at the University of St Andrews.
This is a shortened version of the inaugural annual lecture of the Scottish Constitutional Futures Forum that he delivered at the University of Dundee on 5 June 2013. A video recording of the full lecture is available.