The Brexit process has given rise to many constitutional challenges over the past 2 years going to the fundaments of the UK’s constitution and democracy.  

Constitutional bases

We talk of the UK constitution being unwritten but it’s better to refer to it as uncodified as there are elements of the constitution that are written.  In any event, whilst many countries have codified constitutions they still rely on many unwritten elements to maintain the democratic process, codification can only go so far.   

There have been calls to codify the UK constitution, including during debates over the Human Rights Act, but whilst it remains uncodified it may be said to retain flexibility. That flexibility has certainly been tested in the Brexit process and brings us back to some constitutional basics.

Ultimate sovereignty lies with the Queen in Parliament in which MPs sit not as mandated delegates but as free agents.  The Government is formed of the leadership of the group of MPs that can secure the confidence of the House of Commons to pass legislation.   The sovereignty of Parliament and the role of the Government may give rise to conflict between the two.  Dr Liam Fox, speaking to Andrew Marr recently in relation to recent Brexit events in Parliament, suggested that the Government is the servant of the “People” in differentiation from Parliament and as such is in competition with the sovereignty of Parliament. 

The UK democratic process works on the basis that the elected “Government proposes and Parliament dispenses”.  The Government introduces legislation and Parliament decides whether to amend it and/or pass it into statute.  Amendments may make substantial change to legislation but cannot effectively wreck it. 

Parliamentary sovereignty has limits. A primary limit is that it cannot bind future legislators.  Parliament can delegate its sovereignty or give it up to another body or limit it by, for instance, legislation on principles like human rights.   It can indeed give sovereignty back to the electorate in the form of a binding referendum. It has done that in the recent past but the Brexit referendum was non-binding so Parliament retained its sovereignty over the Brexit question. 

Similarly sovereignty might be hemmed in by international treaty made between governments under, in the UK, Crown prerogative. This is a complex area, particularly when it comes to individual rights and international treaties, but it too might give rise to conflict between Government and Parliament and is a factor in the Brexit debate.

Brexit and the constitution

At the start of this process Miller (Miller and Dos Santos v Secretary of State for Exiting the European Union 2017 UKSC  5) reiterated Parliamentary sovereignty over Crown or Government prerogative and the supremacy of “the will of Parliament” expressed in the FBU (R v Secretary of State for the Home Department, Ex p Fire Brigades Union [1995] 2 AC 513, 552) judgment.  Only Parliament, having legislated to join the EU and affect citizens’ rights in the European Community Act 1972, could remove those rights.  For this reason although the foundation stone of the EU, the Rome Treaty, is an international treaty, the ability to give effect to a withdrawal from it only fell to Parliament.

Many in Parliament now call for Parliament to take control of the Brexit process but this turns the legislative process on its head.   Parliament is not particularly structured to draft or originate legislation or to drive it through the process, which usually has Governmental dynamic.  This is not Parliament’s constitutional role.  Parliament has the ability in this process to pass motions and amend them but those are not binding.  If it really wants to take control it needs legislative power.  It is difficult to see how this will work without innovative machinations of the Speaker, whose own role, as a neutral, also presents constitutional problems. He suggested recently that his role includes defending Parliament but many would debate that.  

Constitutionally and in law the Government retains the whip hand, reinforced by Parliament’s own legislation, The European Union (Notification of Withdrawal) Act 2017 and The European Union (Withdrawal) Act, both passed with large majorities. The Notification Act gave Parliamentary permission to serve the Article 50 Notice.  The Withdrawal Act enacted the withdrawal process, importantly expressing Parliament’s will to withdraw. It also gave the Prime Minister permission to extend the period of the Article 50 Notice. It did, however, also retain a final say for Parliament in section 13 in the “meaningful vote” in which the Government was heavily defeated on 15 January.

The combination of these two statutes means that revocation of the Article 50 Notice would require primary legislation. The ECJ in Wightman (CASE C-621/18, Wightman V Secretary of State for exiting The European Union) confirmed that the Notice can be revoked without EU agreement but domestically, the UK can only revoke with Parliamentary agreement in the form of a statute.

Delaying withdrawal in accordance with Article 50(3) however probably does not need Parliamentary approval (at least in law) and can be affected by the Prime Minister; first because of the terms of section 20(4) of the Withdrawal Act and secondly this probably lies within Crown Prerogative.  Extending the period however does need the unanimous agreement of the European Council.

Politically and practically, if not in law, delaying withdrawal might seem attractive from the UK side.  The procedures to secure agreement on a deal and then negotiating it will take a long time.  Further in legislative terms the UK is simply not ready for withdrawal on 29 March 2019.  There is still a huge body of primary and secondary legislation to be enacted and there simply is not sufficient time for that process. In law, however, we are set to leave the EU on 29 March 2019 whatever may be the readiness.  

The Law Society has made its opposition to a departure without an agreement clear. It takes that stance purely from the practical consequences of doing so.  Amongst many other problems, becoming a third country under GDPR may cause immense difficulties for the transfer of data from the EU.  Achieving adequacy to allow that under GDPR is a 2 year process. Similarly replacing the Brussels Regulations with the Lugano Convention is a two year process.

Will the EU agree to extend the Article 50 period?  The problem there is the European Parliamentary elections which will take place in May.  If we extend the period by any length we must participate in those elections.  The EU had already notionally allotted the UK seats to the rest of the EU27 on the basis we will leave at the end of March.  The Council has planned for the possibility of the period being extended but it remains a problem that some might want to avoid.

Rejection of the Prime Minister’s proposals has, as she rightly said, put us into uncharted territory constitutionally.  The UK is going through a power struggle between the Executive and Parliament the like of which has not been seen for a very long time.  Where we go from here might re-balance the UK constitution and its workings forever.

David Greene is Deputy Vice President of the Law Society of England and Wales