You will be well aware by now of the judgment of the Divisional Court handed down on Thursday 3 November in R (on the application of Miller and others) v Secretary of State for the Exiting of the EU [2016] EWHC 2768 (Admin).  In its highly anticipated decision, the Court has resoundingly ruled that UK constitutional law requires the approval of Parliament before the Government can begin the formal process of leaving the EU.  The constitutional and indeed political importance of this case cannot be underestimated.  

That said (and contrary to the views of the popular press), the Court emphasised that the question before it was one purely of UK constitutional law and that it was not concerned with any views about the merits or demerits of leaving the EU.  The Court’s reasoning was that the Crown does not have the necessary prerogative power to give notice under Article 50 because the European Communities Act 1972 (the “1972 Act”) gives rights to individuals and those cannot be taken away by an act of the executive, ie the Government, unless it has Parliamentary approval to do so.  The Government has been given permission to appeal to the Supreme Court and the case is scheduled to be heard on 7 December.

The case

The judgment resulted from a judicial review brought by a number of campaigners in relation to the Government’s intention to trigger Article 50 of the Lisbon Treaty in March 2017 without Parliamentary approval.  Article 50 provides that “[a]ny Member State may decide to withdraw from the Union in accordance with its own constitutional requirements”.  The claimants argued that invoking Article 50 would remove rights granted by the 1972 Act and therefore could not be done without Parliamentary approval.  The Government submitted that there was an established constitutional convention for the executive to use the Crown’s prerogative powers to withdraw from international treaties and that the power could be exercised to trigger Article 50.

The UK’s constitution and the fundamental principle of Parliamentary sovereignty

Unlike many other states, the UK has no single codified constitution and instead the UK’s constitution is formed of numerous Acts of Parliament, court decisions and conventions.  One of these conventions is the prerogative powers of the Crown, although these powers are usually exercised by ministers on behalf of the Crown.

The Court’s decision emphasised that at the very heart of the UK's constitution is the fundamental principle of the sovereignty of Parliament.  Parliamentary sovereignty means that no person or body is recognised by the law as having the right to override or set aside the legislation of Parliament (arguably one of the key things that Brexiteers campaigned for).  By contrast, prerogative powers were described by the Court as “the residue of legal authority left in the hands of the Crown”.  A critically important aspect of the principle of Parliamentary sovereignty is that domestic legislation is not subject to displacement by the Crown’s prerogative powers. 

The Government sought to rely on the established position that the conduct of international relations and the making and unmaking of treaties are within the scope of the Crown’s prerogative powers and that, therefore, this power could be used to invoke Article 50.  The Court acknowledged that as a general rule those actions are within the scope of the Crown’s prerogative powers. However, as noted above, the Crown cannot change domestic law by any exercise of its prerogative powers; it can conduct international relations and make and unmake treaties but in doing so it is creating legal effects on the plane of international law and it does not and cannot change domestic law.

The Court found the Government’s arguments inconsistent with the fundamental constitutional principle of the sovereignty of Parliament.  It was common ground between the parties that if notice is given under Article 50 it will inevitably have the irrevocable effect of changing the elements of EU law which Parliament had made part of domestic law by enactment of the 1972 Act.  The Government sought to minimise the extent to which the most important rights accrued directly to individuals would be lost, by relying on the fact that many EU Directives and other EU laws have been implemented by domestic legislation and will continue to apply, particularly as a result of the proposed Great Repeal Bill which would re-enact EU law rights in primary legislation.


We think that all concerned would agree that the very nature of our democracy is at stake and constitutional concepts such as the independence of the judiciary and thereby the separation of powers, rightly or wrongly, are under attack.

Meanwhile, arcane legal arguments will likely dominate the actual decision.  For instance, the Court held that despite the absence of clear wording in legislation to this effect,  Parliament should be taken as having intended to legislate by the 1972 Act so as to introduce EU law into domestic law in such a way that it could not be undone by exercise of prerogative power.  This particular issue (amongst others of course) is likely to be hard fought before the Supreme Court, as it is arguably one of the weaker points in the case.

The Prime Minister intends to trigger Article 50 by the end of March 2017 and due to this strict timeline the Government has been given permission to appeal the decision directly to the Supreme Court.  The case is expected to be heard on 7 December 2016. The constitutional importance of this case cannot be overstated and we will follow this up with a further update as soon as we know more.

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Melanie Carter

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Emma Dowden-Teale


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Claire Whittle

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Posted on 07/11/2016 in Brexit Briefcase

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