I have just finished work on a paper entitled “Constitutional legislation, European Union law and the nature of the United Kingdom’s contemporary constitution”. It will be published in the European Journal of Constitutional Law in December 2014.
The paper is concerned with the recent judgment of the UK Supreme Court in R (HS2 Action Alliance Ltd) v Secretary of State for Transport  UKSC 3,  1 WLR 324 (about which I have written before on this blog). In HS2, the Supreme Court gives some support to the notion of ‘constitutional statutes’ — a concept that, although proposed by Laws LJ more than a decade ago in Thoburn v Sunderland City Council  EWHC 195 (Admin),  QB 151, is essentially novel in UK constitutional law. The Court in HS2 also engages with questions about the relationship between domestic law and European Union law in a way that — given the paucity of constitutional analysis undertaken by the House of Lords in R v Secretary of State for Transport, ex parte Factortame Ltd (No 2)  1 AC 603 — is arguably unparalleled at the apex-court level in the UK. For these reasons, the HS2 judgment is of considerable constitutional significance.
The following is an extract from the beginning of the article, which gives a sense of the issues it addresses and the lines I take:
There are many things that distinguish the United Kingdom from its continental neighbours. One of them is the absence of a written constitution. Another is the absence of a high-speed rail network of the type that many European countries built decades ago and now take for granted. The latter gap may be filled by the construction of ‘HS2’, a new high-speed railway that is intended to link several major English cities. In contrast, there is no immediate prospect of a written constitution. However, the decision of the UK Supreme Court in R (HS2 Action Alliance Ltd) v Secretary of State for Transport (‘HS2’), in which the decision to go ahead with HS2 was challenged, arguably points towards a British constitution that—while still unwritten, in the sense of there being no uniquely authoritative governing text—is richer and more complex than is usually supposed. And while it would be going too far to suggest that the HS2 case is as transformative of the UK’s constitutional landscape as the HS2 network might be of England’s rural landscape, the constitutional implications of the Supreme Court’s judgment are nevertheless highly significant.
This paper argues that three aspects of the HS2 case form part of a constitutional tableau that exhibits characteristics which are either novel in themselves or which presuppose readings of the constitution that are in some respect novel. First, the case acknowledges that the UK constitution now differentiates between ‘constitutional legislation’ and ‘ordinary legislation’—a legal distinction that was, until very recently, entirely alien in the British context. Second, HS2 indicates that the former category may itself be hierarchically nuanced, some constitutional legislation (and principles) being more fundamental than others—an insight that impacts upon the way in, and the extent to, which European Union law is considered to enjoy primacy in the UK. Third, and most broadly, the HS2 judgment forms part of a wider narrative arc being advanced by the UK’s senior judiciary, according to which the central notion of parliamentary sovereignty falls to be understood within a constitutional framework that is increasingly rich in nature.