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Brexit, article 50 and the separation of powers

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The Supreme Court’s decision of 24 January 2017 is the most significant case in constitutional law for decades. It did not rule on the merits, or the timing, of the UK’s exit from the European Union. But it did confirm EU law as one of the sources of UK law. The court reasserted the authority of Parliament over ministers, holding that only Parliament has the right to take the momentous step of triggering article 50 of the Treaty of Lisbon.

Immediately following the passing of the European Communities Act (ECA) 1972, the government ratified the Treaty of Accession. The UK became a member of the EEC on 1 January 1973. As with most couples entering into matrimony, no thought was given to divorce. Neither ECA 1972 nor the European Treaties provided for the exit of a member state. This option was only added in 2007 by article 50 of the Lisbon Treaty.

Section 2(1) of ECA 1972 provides that ‘all rights, powers, liabilities, obligations and restrictions from time to time created or arising by or under the Treaties, and all such remedies and procedures from time to time provided for by or under the Treaties, as in accordance with the Treaties, [are to be given full legal effect in the UK without further enactment].’

The European Referendum Act 2015 made provision for a referendum on whether the UK should remain in the EU, but did not specify how a ‘Leave’ vote should be implemented. The government subsequently announced that they alone would decide when to invoke article 50, acting under the royal prerogative and without Parliamentary debate. In R (on the application of Gill and others) v Secretary of State, the applicants challenged this as unlawful, because invoking article 50 will alter domestic law and take away rights enjoyed by individuals. This challenge was upheld by the Divisional Court: see [2016] EWHC 2768 (Admin). The secretary of state appealed. The full Supreme Court gave judgment on 24 January 2017 ([2017] UKSC 5).

The issues and rival contentions

As the court was at pains to point out, judges do not intrude into the realm of politics (see para 3 of the judgment). Their role is to uphold and further the rule of law (para 42). The main question, therefore was not whether, but how, article 50 should be invoked. Two constitutional rules are in play. The first is that the making and unmaking of treaties is a matter of foreign relations and within the Crown’s prerogative, as exercised by the executive. The second is that the executive cannot alter the law made by Parliament or the common law or custom of the realm (para 5). In the present case, these two rules are capable of producing opposite conclusions (para 277). A further issue (the devolution issue) (para 10) concerned whether the prior consent of the devolved administrations in Northern Ireland, Scotland and Wales is required before triggering article 50. The court heard oral argument over four days and considered ‘a library’s worth’ of authorities (para 159) and academic writings (para 11).

The secretary of state argued that the UK’s relationship with the EU exists on the international plane. ECA 1972 is a conduit pipe through which EU law flows into the domestic legal system, but only for so long as the UK remains a member of the EU. Brexit involves a partnership between the electorate, the executive and Parliament to cut off that flow. UK domestic legislation, in the form of a Great Repeal Bill (GRB), will be enacted to define and safeguard individual rights. ECA 1972 does not expressly abrogate the Crown’s prerogative to make and unmake treaties. Nor does it do so by necessary implication. The position is analogous to the UK’s decision to leave the European Free Trade Association (EFTA), or the implementation of double taxation agreements (DTAs). Further support can be found in the statutes enacted subsequently to ECA, particularly the European Union Act (EUA) 2011, which imposes certain restrictions on the powers of ministers to agree treaty changes at EU level. But, as these statutory restrictions do not apply to an article 50 notification, this means Parliament must have intended to preserve use of the royal prerogative to terminate membership.

The applicants’ arguments focused on the unique nature of membership and the primacy of EU law. ECA 1972’s language is incompatible with use of the royal prerogative to unmake that law. This is only available in cases not covered by statute and cannot be used to frustrate Parliament’s intention. Later statutes do not support the secretary of state’s argument and, in any event, are not to be read as one with ECA 1972. The rule of recognition (a principle of constitutional law which requires that sources of law should be clearly identifiable) would be infringed because ECA 1972 makes EU law part of UK law. Triggering article 50 will inevitably bring about a change in individual rights.

The decision

By a majority of eight justices to three, the court dismissed the secretary of state’s appeal. The court took the opportunity to restate some important principles of constitutional law:

  • Parliamentary sovereignty is fundamental and involves the right to make or unmake any law whatsoever (para 43).
  • The royal prerogative survives as a relic (paras 48–49) and is now exercised by the executive who are answerable to Parliament (para 45).
  • Most of the royal prerogative has been curtailed or abrogated. It is not available in cases covered by statute (para 47). It cannot be used to frustrate a statutory purpose or empty it of content (para 51).
  • Individual rights may only be affected where those rights are inherent in the prerogative power (para 52) (for example, a declaration of war leading to an individual becoming punishable for treason) (para 53).
  • Subject to the above, the prerogative includes the power to make and unmake treaties (paras 54–55). Since these operate on the international plane, they are not part of domestic law unless transposed as such (para 56).

Applying these principles, the court focused on the unique character of the Treaty of Accession and ECA 1972 which, the court stated, do not merely operate on the international plane. They authorise a dynamic process by which, without further primary legislation (and in some cases even without domestic legislation) EU law not only becomes a source of UK law but also takes precedence over all domestic sources of law including statutes (para 60). ECA 1972 has a constitutional character (para 67) and creates a fixed rule of domestic law (para 82). Where EU law applies in the UK, it is the relevant EU institutions which are the source of law. ECA 1972 operates as a partial transfer of law-making powers until Parliament decides otherwise (para 67-8). The court rejected as ‘unreal’ the secretary of state’s argument which denied that, while ECA 1972 remains in force, the Treaties etc. are direct sources of UK law; nor can EU law properly be compared with delegated legislation (paras 61, 68). Moreover, adopting the conduit pipe metaphor, withdrawal from the EU would completely remove the conduit (as opposed to the contents which, from time to time, flow through it) (para 84). There is a vital difference between withdrawal and variation. Withdrawal will bring about a fundamental change in the constitutional arrangements of the UK (paras 78, 81). The loss of a source of law is a fundamental legal change (para 83). Neither ECA 1972, nor later statutes, contemplated or accommodated the abrogation of EU law by prerogative act. Any change in the law to give effect to the referendum must be made in the only way permitted by the UK constitution, namely by an Act of Parliament (para 82). To proceed otherwise would be a breach of settled constitutional principles stretching back many centuries. The analogy with withdrawal from EFTA is not apposite, as that agreement created no directly effective rights and withdrawal was the corollary of the UK joining the EU (para 97). Nor is the analogy with DTAs, which are entered into under what is now s 2 of the Taxation (International and Other Provisions) Act 2010 and have effect only if specified in an Order in Council approved by the House of Commons (para 98).

Minority view

Lords Reed, Carnwath and Hughes gave dissenting judgments (paras 153–283). They reasoned that ECA 1972 creates a statutory scheme which is conditional. It operates only so long as the UK remains an EU member. The scheme ensures that domestic law exactly matches UK treaty obligations as they may be ‘from time to time’. When EU membership ceases, those obligations automatically cease. The article 50 procedure does not itself alter those rights. It merely begins the process ultimately achieved by the GRB. ECA 1972 does not answer the key question. The answer appears instead from EUA. By implication, EUA preserves the prerogative power, subject only to the express restrictions it lays down.

The devolution issue

The court unanimously rejected the argument that prior consent is required from the devolved administrations (paras 135, 242, 243 and 282). In light of the majority decision, however, this was academic to the main question.

Where does this leave us?

Events moved swiftly after the hearing. The prime minister gave a speech setting out a 12-point plan for Brexit to include exiting the single market. On 25 January 2017, she promised to issue a White Paper. The court declined to rule on what kind of legislation is required to trigger article 50 (para 122) and, on 26 January, the European Union (Notification of Withdrawal) Bill was laid before Parliament and given its first reading. There is one, and only one, operative clause:

‘(1) The Prime Minister may notify, under Article 50(2) of the Treaty on European Union, the United Kingdom’s intention to withdraw from the EU.

‘(2) This section has effect despite any provision made by or under the European Communities Act 1972 or any other enactment.’

At the time of writing, the second reading is fixed for Tuesday 31 January, with a vote the next day. The Bill will then enter the committee stage. This is the stage when amendments may be tabled. One which has been suggested is the retention of all existing EU rules on tax avoidance and evasion. It remains to be seen whether any amendments take root or are ruled out of scope. Report stage and third reading follow. The government intends these should be completed by 9 February. Passage through the House of Lords, to begin on 20 February, may be stormy given the absence of a government majority. It has the potential to provoke a constitutional crisis if the Lords reject the bill. Litigation has so far proceeded on the agreed basis that article 50 notice cannot be qualified or conditional and once given cannot be withdrawn. The Supreme Court, however, declined to express a view (para 26). Further Brexit challenges are in prospect: a case in the Irish courts on the interpretation of article 50; and an English judicial review based on article 127 of the European Economic Area Agreement. The claim is that leaving the EEA (a matter not covered by the referendum) requires primary legislation.

While the continuing uncertainty is nerve-racking for businesses and their advisers, some comfort can be drawn from the Supreme Court’s clear ruling that, while the UK remains a member of the EU, the rights and safeguards which EU law provides for individuals must continue to be recognised, available and enforced as an important source of UK domestic law. The court’s decision is a landmark ruling on the separation of powers between the legislature, the executive and the courts. It should be a cause for celebration by both sides in the Brexit battle. Those who pilloried the Divisional Court judges for their decision would do well to reflect that a main driver in the ‘Leave’ campaign was the demand to regain full Parliamentary sovereignty. The Supreme Court’s decision has affirmed that fundamental principle of our constitution.