Can Brexit still be prevented?

On 23 June, voters in the UK chose to leave the EU.

Does that make a Brexit inevitable? Or are there still ways in which it could be averted?

We previously pointed out that the outcome of the referendum was not legally binding. Now that the initial shock of that outcome has subsided, questions are being asked as to what this means. What further legal steps need to be taken to extract the UK from the EU, and is there a possibility that they will never happen?

In this alert we answer some of those questions, including whether it will be for the government or Parliament to make a decision to trigger a Brexit, whether the EU can force us to leave, and whether Scotland could really prevent that outcome.

Is Brexit inevitable?

The mechanism for the UK's withdrawal from the EU is set out in Article 50 of the Treaty on European Union (the 'TEU' or Lisbon Treaty).

Although Vote Leave suggested some (legally dubious) alternative means of withdrawal during the referendum campaign, the consensus is that Article 50 is the correct route by which to effect a Brexit.

From being an obscure provision in an international treaty only weeks ago, Article 50 has now been catapulted onto centre stage. As minds turn to how the Brexit process actually works, much current discussion has focused on the first paragraph of Article 50 and the opening sentence of the second. These contain two deceptively simple statements -

1. Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements.
2. A Member State which decides to withdraw shall notify the European Council of its intention...

Several things are clear from these provisions. Firstly, there must be a decision by a member state to leave the EU. Secondly, that decision must be taken in accordance with the member state's own constitutional arrangements. Thirdly, once a decision has been made in accordance with those arrangements, the member state must notify it to the European Council.

Many, in the UK and also (more especially) the wider EU, appear to have jumped to the conclusion that the outcome of the referendum was a decision to leave the EU for the purposes of Article 50.

This is not the case. The result of the referendum has no effect in domestic law. This is because there is no provision in the European Union Referendum Act 2015 which says either that the result itself constitutes a decision to leave or that it is to be treated as a binding instruction to government. That position must be treated as the deliberate intention of Parliament, because it is in stark contrast to the legislation governing other referendums.

For instance, under the Parliamentary Voting System and Constituencies Act 2011, the result of the alternative voting referendum gave rise to an obligation on the relevant minister (depending on the outcome) either to make an order adopting proportional representation or to refrain from making that order.

Again, in referendums held under the European Union Act 2011 in relation to amendments to the EU Treaties, the Act provides that, where a majority of voters have rejected ratification of such amendments, this must be respected.

In both cases, the outcome of the referendum gives rise directly to legal consequences. This is not the case in relation to the outcome of the referendum on 23 June, and it is clear that Parliament did not intend it to be.

The outcome of the referendum cannot therefore constitute the UK's decision to leave the EU. Something more is required before the UK can serve an Article 50 notice 'in accordance with its own constitutional requirements'. But what?

Who decides - Government or Parliament?

Plainly, a further decision is needed to serve an Article 50 notice. However, if not the voters in the referendum, who makes that decision under the UK's 'constitutional arrangements'?

It is important for the decision to be taken by the correct person or body. An unlawful decision would not meet the test in Article 50(1) and could not, in domestic or EU law, form the basis for a notification under Article 50(2). An unlawful decision would certainly be litigated.

That question has quickly become the subject of debate among constitutional law academics, counsel specialising in public law, and former members of the judiciary. Opinions are divided, with some suggesting that the government can make the decision in law and others that it is for Parliament to decide.

Our view is that it is for Parliament to make the decision to leave the EU, and only with Parliamentary authority can an Article 50 notice be issued. We suggest that a decision by the government made without reference to Parliament would be open to a successful challenge.

The limits on the Government's powers

To understand why this is the case, we first need to explain the alternative position, which is that the decision could be made by the Prime Minister using prerogative powers.

Prerogative powers are those powers which traditionally existed in the person of the monarch and which do not derive from statute. These days those powers are exercised by Ministers in accordance with the legal principle that they are exercised on behalf of the Crown. They include a rag-bag of residual powers but, most importantly for present purposes, those relating to foreign affairs - such as the making (and unmaking) of treaties.

The UK signed up to the Treaty of Rome - the precursor of the current treaties which underpin the EU - in 1972 through exercise of prerogative powers. One argument is that the exercise of those powers could equally be used to leave the EU by taking the UK out of the EU Treaties.

There are two reasons why this view is problematic.

The first is that the Courts have held that prerogative powers cannot be used to override or frustrate the will of Parliament as expressed in statute (see R v Secretary of State for the Home Department, ex p Fire Brigades Union). Prerogative powers may have been used to sign the UK up to the Treaty of Rome. However, for European Economic Community law (as it then was) to be capable of being given full effect in the UK, Parliament needed to pass the European Communities Act 1972 (the '1972 Act').

Section 2 of the 1972 Act gave domestic legal effect to the corpus of EEC law - both as it stood when the Act came into effect and as it would be amended and added to in the future. Parliament therefore clearly intended to make EEC - now EU - laws part of the UK's domestic legal framework.

A decision to leave the EU and to issue an Article 50 notice would set in train a process of withdrawal which, once concluded, would mean that the EU Treaties and the directly effective EU legislation made under them would cease to apply to the UK. After a notice was given there would be no action that Parliament could take to prevent a Brexit.

Although (under the Constitutional Reform and Governance Act 2010) Parliament would get a chance to object to the ratification of the withdrawal agreement negotiated following the notice, that would simply be a say on the terms on which the UK left the EU - not the fact of Brexit itself. If Parliament refused to ratify the withdrawal agreement, the UK would simply leave the EU without any provision being made for any particular form of ongoing relationship between the two.

Returning to the Fire Brigades Union case, the prerogative power to issue an Article 50 notice would therefore be trumped by statute in the form of the 1972 Act. The power would otherwise frustrate the terms and purpose of that Act, which is impermissible.

There has been some debate about whether or not an Article 50 notice would indeed frustrate the will of Parliament as expressed in the 1972 Act (with views from Carl Gardner and Mark Elliott that it would not). In our view there is little doubt that in the real world this is exactly what would happen.

The Special Status of the European Communities Act 1972

There is, however, a second and much deeper set of concerns relating to the legality of using the prerogative power to withdraw from the EU. To our knowledge, these have so far escaped comment in the debates around this issue.

These concerns arise from the fact that the 1972 Act is no ordinary statute. It has been recognised by the Supreme Court as being one of a number of 'constitutional instruments' - a special category of statutes which form part of the constitution of the UK. These include Magna Carta, the Bill of Rights, the Acts of Union 1707 and the Human Rights Act 1998 (R (HS2 Action Alliance Ltd) v Secretary of State for Transport).

Constitutional instruments have a special status. They are not, for example, subject to the doctrine of implied repeal (under which, in line with the principle that Parliamentary sovereignty means that no Parliament can bind a future Parliament, a provision in an earlier statute is deemed to have been changed by an incompatible provision in a later statute). Parliament can still amend constitutional instruments but it cannot impliedly do so - there must be an express statement to that effect in the amending statute which puts beyond all doubt that this was Parliament's intention (BH & Anor v The Lord Advocate & Anor).

So, not only is the 1972 Act an expression of the will of Parliament to be bound by EU law, but that expression of will is contained in a statute which has been held by the Supreme Court to be one of those pieces of law which make up the UK's constitution. Even Parliament itself can only amend these laws by doing so in clear and express terms.

A decision by the government to leave the EU by issuing an Article 50 notice without recourse to Parliament may be, in form, an exercise of the royal prerogative in the field of foreign relations. In substance, however, it would be an amendment to the UK's constitution. This is beyond the scope of the prerogative powers.

Therefore, in addition to the fact that the use of the prerogative would be unlawful because it would frustrate an existing statute, it would also be unlawful because it would amount to an amendment of the constitution by an executive decision. Such a use of prerogative powers without prior recourse to Parliament would offend fundamental principles dating back to the Bill of Rights.

The only possible answer to this, floated by the Cambridge academic Kenneth Armstrong, is that in some way the referendum as an exercise in direct democracy trumps representative democracy - that the government had got its constitutional authorisation from the people without the need for the people's will to be mediated through Parliament. The flaw in this argument is that the UK's constitution is that of a representative democracy with sovereignty residing in 'the Queen in Parliament'. This is in contrast to Switzerland, or certain states in America, where elements of direct democracy through referendums have constitutional force.

The UK's referendum cannot therefore be seen as an exercise in direct democracy but as a way for Parliament to test public opinion on the issue of the UK's continuing membership of the EU. If it was intended to be anything else, the European Union Referendum Act 2015 would have had to make it so, and it did not. The argument returns full circle to the fact that the referendum is not legally binding.

Having tested the opinion of the people, the correct course is for Parliament to take the next step and to consider whether to leave the EU and authorise the issue of an Article 50 notice.

Could MPs vote against Brexit?

So what happens when MPs are confronted with the question of pulling the trigger on Brexit - could they choose not to despite the result of the referendum? As a matter of law, they could.

In the case of Moohan v Lord Advocate, which concerned the right of convicted prisoners to vote in the Scottish independence referendum in 2014, Lord Neuberger touched upon the effect of the outcome of that referendum -

'If there had been a "yes" vote, Scotland would not have achieved independence unless and until the UK Parliament had voted in favour, and, whatever the main parties had promised, Members of Parliament would have been free, indeed constitutionally bound, to vote as they saw fit.' (emphasis added)

This is a striking statement by the Supreme Court. It encapsulates the notion of MPs, not as mere delegates of their constituency sent to Parliament to act on the wishes of voters, but as trustees whose duty is to do what they think best in any particular situation.

This (essentially Burkean) view has long had a place in political theory and practice, but according to Lord Neuberger it goes beyond that and is actually a matter of constitutional obligation on MPs.

As a matter of practical politics, however, there are considerations which impact on the way that an MP votes. The first is the system of 'whipping', whereby MPs are encouraged with greater or lesser degrees of severity to 'toe the party line' by voting in a certain way. An MP may be disciplined by his or her party for not doing so. It is doubtful that either of the two largest parties would do anything other than require their MPs to vote in favour.

The second practical consideration is the fact that most MPs will be concerned about their ability to be re-elected at the next general election. An MP from a constituency which voted to leave the EU, as the majority did, would be taking a brave stance in voting against issuing an Article 50 notice, even if to do so would accord better with his or her view of the best interests of the country.

That calculation could of course be altered by a significant shift in the complex factual matrix that surrounds the Brexit negotiations, if such a shift swings public opinion in favour of remaining in the EU.

For example, the EU Trade Commissioner has recently stated that in her opinion, talks on the UK's ongoing trading relationship with the EU would only take place after the Article 50 process had been completed and the UK had left the EU. That would mean that there was a period between leaving the EU and a new trade deal being in place during which UK - EU trade would be governed simply by the World Trade Organisation's rules, giving rise to high tariffs in various sectors. (And that period could potentially be lengthy; the EU's trade deal with Canada has taken seven years to negotiate and is still not formally commenced.)

For the record, we consider that the Trade Commissioner's approach does not accord with Article 50. However, legal accuracy aside, such comments from a senior EU official illustrate that it is far from inevitable that MPs as a whole will take a view that leaving the EU is in the UK's best interests.

If the only terms on which a Brexit is possible look to be damaging to the interests of the country, MPs have a constitutional duty to engage in certain rational calculations. Brexit could be delayed for a time, or indefinitely. Parliament could seek the cover of a second referendum.

If the period since the referendum has proved anything, it is the truth of Harold Wilson's dictum that 'a week is a long time in politics'. In the matter of what happens next, there is a considerable amount still to play for.

Can the EU force the UK to leave?

As temperatures ran high the day after the referendum, President of the European Parliament, Martin Schulz, told the Guardian that EU lawyers were studying whether it was possible to speed up the triggering of Article 50, adding that he doubted that the timing of Article 50 was down to the UK alone.

The suggestion that the EU could somehow force the UK to issue an Article 50 notice carries no legal weight. This is because, as discussed above, an Article 50 notice can only follow a decision by the UK, in accordance with its constitutional arrangements, to leave the EU. No such decision has yet been made, and none appears imminent.

However, once it has made that decision, the UK will be under an obligation to provide notification of its intention to withdraw ('A Member State which decides to withdraw shall notify the European Council of its intention'). If a decision were made but no Article 50 notice followed, the EU could theoretically bring infringement proceedings against the UK under Article 258 of the Treaty on the Functioning of the EU (the 'TFEU').

Even should such proceedings be brought, they could result only in a declaration of breach, although failure to then issue an Article 50 notice could lead to proceedings under Article 260 TFEU for failure to comply with the Court of Justice of the European Union's (CJEU) judgement. That could result in the absurd position of the UK being fined by the EU for not leaving. The realistic prospects of such a scenario are incredibly remote.

The reality is that there is no legally effective mechanism for forcing the UK to leave the EU. At this stage, these matters arise only in the sphere of politics.

Can Scotland (or Northern Ireland) block Brexit?

The demographics of the referendum were such that although overall the UK voted to leave the EU, a majority of voters in both Scotland (62%) and Northern Ireland (55.8%) voted to remain.

On the Sunday following the Brexit vote, Scotland's First Minister, Nicola Sturgeon, told the BBC that the Scottish Parliament could attempt to block a Brexit by refusing to consent to any changes that would need to be made to the legislation that underpins devolution to Scotland.

The threat is a reference to the Sewel Convention under which the Westminster Parliament will not normally legislate with respect to devolved matters, or amend the powers of the devolved legislatures, without the consent of the devolved legislature in question.

The convention is embodied in a Memorandum of Understanding between the UK government and the devolved executives. In relation to Scotland, the Sewel Convention is also referred to in an amendment to the 1998 Act by the Scotland Act 2016, which states 'it is recognised that the Parliament of the United Kingdom will not normally legislate with regard to devolved matters without the consent of the Scottish Parliament' (a similar provision with respect to Wales is found in the current Wales Bill).

The argument is that, as the Scotland Act 1998 defines the legislative competence of the Scottish Parliament by reference to compliance with EU law, a Brexit will require an amendment to that Act and the Scottish Parliament can withhold consent to that amendment.

The 2016 Act merely recognises the existence of one element of the Sewel Convention. It refers to devolved matters but not the powers of the Scottish Parliament and it is those powers which are at issue here. The Scottish Parliament would therefore be required to rely on the Sewel Convention.

There is an interesting piece to be written on whether the Sewel Convention could be used to challenge a decision by the UK Parliament to press on with legislation following a refusal of consent by the Scottish Parliament. For present purposes that question is, however, a red herring. This is because any amendment to the 1998 Act will be made after the UK has withdrawn from the EU. The Sewel Convention cannot be used to prevent the Brexit that would render such an amendment necessary. This means that even if the Sewel Convention could be used to block amendments to the 1998 Act, the UK will still have left the EU: the only effect will be the retention of a redundant provision in that Act.

The same would apply to the withholding of legislative consent by the Northern Ireland Assembly to a similar amendment to the Northern Ireland Act 1998.