There is no doubt that 24 January 2017 was a big day for the Supreme Court. That was the date on which 11 Justices handed down their decision in R (on the application of Miller and another) v Secretary of State for Exiting the European Union  UKSC 5.
At issue was a fundamental constitutional question: could the decision of the UK to exit the European Union be implemented by the Government itself exercising executive power deriving from the Royal Prerogative, or did the process have to be authorised by Parliament passing a Bill which would give the Government the power to start the exit process.
The Government argued – in outline – that the power of the UK Government to enter into international treaty obligations is something that is exercised by exercise of prerogative powers. Thus, equally the Government argued – the power to disengage from treaty obligations could be done by exercise of those same prerogative powers.
Those who challenged the Government’s position argued that because accessing the EU had been accompanied by the enactment of the European Communities Act 1972, (which gave domestic effect to the UK’s obligations under the then existing EU Treaties, together with subsequent statutes, which gave effect to and related to later EU Treaties, and the European Union Referendum Act 2015) the Act of 1972 had created legal rights and obligations in our domestic law. Owing to the well-established rule that prerogative powers may not extend to acts which result in a change to UK domestic law, and withdrawal from the EU Treaties would change domestic law, the Government cannot serve a Notice unless first authorised to do so by an Act of Parliament.
By a majority of 8 – 3, the Supreme Court upheld the decision of the High Court that the process of starting Brexit could not be started by the exercise of the prerogative, but must be authorised by an Act of Parliament.
The Supreme Court acknowledged that the 2016 referendum was an event of great political significance. However, its legal significance had to determined by what Parliament included in the statute authorising it, and that statute simply provided for the referendum to be held without specifying the consequences.
The change in the law required to implement the referendum’s outcome must be made in the only way permitted by the UK constitution, namely by legislation.
There has been a great deal of comment – much of it vitriolic and ill-informed – on the decisions of the courts. Those who argued in favour of the Government appeared to have forgotten some basic constitutional principles.
- The Sovereignty of Parliament means that Parliament ( not the Executive) has the power to make and unmake laws (indeed that was a key argument of the case for Brexit – that the UK had ceded too much law making power from the UK Parliament to the EU).
- The Separation of Powers means that there are checks and balances in our constitutional settlement, which implies that the judiciary must have the independence to reach decisions that the Government of the day may not like.
It can be argued that the Secretary of State for Justice and Lord Chancellor Mwas too slow to uphold her obligations under section 3 of the Constitutional Reform Act 2005 to uphold the continued independence of the judiciary – certainly in the immediate aftermath of the initial High Court decision in which considerable abuse was heaped upon the judges. Those who accused the judges of ‘being out of touch’ showed that they had no understanding of what the role of the judges is and should be in a parliamentary democracy.
Of course, those in power who find that they are prevented from doing what they would like may be expected to rail against those who have put barriers in their way – recent events in the USA bear witness to this proposition. But it should be remembered that without checks and balances, government leaders may well be tempted to take more and more power to themselves, with potentially extremely serious consequences for the people they seek to govern.
One further question that this case provokes is whether the current mix of constitutional principle – the precise limits of which are unclear – and law is the mot appropriate basis on which the Constitution of the UK should be founded. Is one implication of the Miller case that the time has now come for the UK to adopt a written constitution?