Brexit troubles: does the UK need a written constitution?

This post was contributed by Ms Charlotte Crilly, Teaching Fellow and Module Convenor for Undergraduate Laws.

Constitution 4th July

It is undeniable that this is an interesting time to be studying public law. One well-known legal commentator said in April that

  • Now, constitutional law must be the most exciting subject on the legal curriculum. There probably has been no more fascinating a time to be an English constitutional lawyer since the 1680s, with the deposition of a king and the enactment of the so-called Bill of Rights in 1689. And a good part of this, although not all, is because of Brexit. (Read David Allen Green’s, 1 April 2019, ‘Brexit tests the British constitution’ at Financial Times).

One of the legal questions thrown up by Brexit has been whether the UK needs a written constitution. You will know that the United Kingdom is almost (though not quite) unique in the world in not having a ‘written’ constitution. By this is meant that there is no one single document that sets out what the constitutional arrangements are; instead the constitution is found in a number of statutes, case law decisions, constitutional conventions and constitutional principles (see Chapter 2 of the public law Module Guide). Many of these sources are in fact written down, so it is more accurate to say that the constitution is uncodified, rather than unwritten.

The calls for a written constitution are based on the argument that the Brexit process has shown the current constitutional arrangements to be wanting. Particularly in the light of the prorogation of parliament in September 2019 and the resulting prorogation cases in the Supreme Court  (R(Miller) v The Prime Minister, Cherry v Advocate General for Scotland [2019] UKSC 41), it has been argued that a written constitution with a clear set of principles and rules is needed to promote legal certainty and to prevent abuses of power. Ambiguous constitutional provisions arguably allow the executive to choose which of conflicting or unclear principles it will follow.

Moreover, a written constitution would enable fundamental human rights to be protected in law. There are a large number of rights (for example employment rights) that are currently contained in EU law. And although the Human Rights Act and the European Convention on Human Rights would not be directly affected by leaving the European Union (the Council of Europe is a separate body), it is very possible that the debate on these rights would be reopened post-Brexit.

The other side of the argument is that a written constitution would not in fact have made a difference to the constitutional waves caused by Brexit, and would not necessarily be an improvement. The unwritten constitution has worked well over a long period of time and has the advantage of flexibility, while a new constitution could cause a period of instability. Would a written constitution politicise the judges and lead to more constitutional cases in the courts? And how in any case would a written constitution be decided; is there in fact any consensus on what a new constitution should look like?

Following the Supreme Court’s decision in R(Miller) v The Prime Minister, Cherry v Advocate General for Scotland [2019] UKSC 41, the MP Caroline Lucas asked the Attorney General in parliament

  • While yesterday’s Supreme Court decision upholding parliamentary sovereignty was extremely welcome, it should never have come to this. Our centuries-old unwritten constitution, based on gentlemen’s agreements, is not fit for purpose when dangerous populists are in office. Will the Attorney General therefore consider urgent proposals for a written constitution, developed with real citizens’ engagement, since our democracy belongs to all of us, not just those who think they are above the law? (Hansard 25 September 2019, vol 664, col 664, at

The Attorney General’s response was that

  • I have a degree of sympathy with what the hon. Lady says. I think that, as we depart the European Union, there is ground for thinking again about our constitutional arrangements and how they should be ordered. I think that, in doing so, a widespread public consultation of the kind that she is describing would be essential, because any new constitutional arrangements would have to be sanctioned by the widest possible public support and assent, so I do have some sympathy. No doubt over the coming months and years, this will be a subject of important concern to the House. (Hansard 25 September 2019, vol 664, col 664, at

Although it is not the highest political priority, it does seem that constitutional issues raised as a result of Brexit have ignited at least to some extent a debate about the necessity or desirability of a written constitution. Even in the absence of wholesale change, some more modest changes may be made over time. Why not follow up some of the reading resources suggested below, and put together your own arguments for or against a written constitution for the United Kingdom?


One comment

  1. This has been written well and I do agree that Brexit will call for some form of change but I do not see how the UK having a written constitution would prove to be a massive improvement.

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