UK Constitutional Law Association

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Ewan McGaughey: What Is Needed in Our Constitution to Revoke Article 50?

Professors Gavin Phillipson and Alison Young have argued on this blog that an Act of Parliament is needed to revoke article 50. An alternative view is that, while an Act may be desirable, it is not necessary. This is still an important issue because on Wednesday 27th of March 2019, 184 votes in the House of Commons were cast in favour of revoking article 50 before ‘exit day’ if no agreement had been reached, 293 votes were cast against, and 164 MPs abstained. By contrast, 400 MPs voted against ‘no deal’. Mathematically the question of revocation remains in play, because in an emergency a positive majority of the Commons may emerge. Because an Act takes longer than executive action, the question of the legal mechanism to revoke article 50 must be scrutinised.

Arguments that revocation of article 50 would frustrate statute

One possible starting point is that Advocate General Campos Sánchez-Bordona at [145] of his opinion in Wightman v Secretary of State for Exiting the EU (2018) C‑621/18 said that because triggering article 50 required Parliament’s authority, it was ‘logical, in [his] view, that the revocation of that notification also requires parliamentary approval’. This appears to have misunderstood R (Miller) v Secretary of State for Exiting the EU [2017] UKSC 5, which decided that triggering article 50 risked depriving citizens of rights guaranteed by Acts of Parliament. Deprivation of rights requires a new Act. But revoking article 50 threatens nobody’s statutory rights: it protects them. On that basis alone an Act is not needed.

Professors Gavin Phillipson and Alison Young make a different, forceful argument that ‘using the prerogative to revoke Article 50 would frustrate [the] purposes’ of the European Union (Withdrawal) Act 2018. First, it is argued following Lord Browne-Wilkinson in R v Home Secretary, ex parte Fire Brigades Union [1995] UKHL 3 that prerogative powers cannot ‘be validly exercised by the executive so as to frustrate the will of Parliament as expressed in a statute’. Second, Phillipson and Young say Miller (even if one disagrees with its result) has reaffirmed the principles set out in FBU (at [35] and [51]). Third, they say the ‘whole purpose of the Act is to facilitate the UK’s actual exit’ and it is unpersuasive to say the Act merely expresses an incomplete ‘intention’ to that effect. Fourth, they say this ‘conclusion is reinforced when we examine’ sections 8 to 12, which enable Ministers to write delegated legislation upon withdrawal for any ‘deficiency’, to implement the withdrawal agreement, and to change the restrictions of devolved legislatures to not act incompatibly with the Act rather than EU law. Fifth, the power of a Minister in section 20(4) to ‘amend the definition of “exit day”’ to ‘the day and time that the Treaties are to cease to apply to the United Kingdom’ would, they say, ‘be rendered devoid of purpose’ and ‘meaningless’.

Reasons that revocation of article 50 would not frustrate statute

The arguments of Professor Phillipson and Young must respectfully be rejected for at least five reasons. First, in the FBU case, on which Phillipson and Young rely heavily, the Home Secretary (Michael Howard) had a statutory duty to introduce a criminal injury compensation scheme, and it was this duty that would have been frustrated if the scheme was never introduced. According to Lord Browne-Wilkinson it was ‘of central importance’ that this duty was ‘itself in force’. But section 1 of the EUWA 2018 is not in force.

Second, even if section 1 of the EUWA 2018 were in force nobody has a duty in relation to exit day. Parliament gave ministers the power to ‘amend the definition of “exit day”’ to ‘the day and time that the Treaties are to cease to apply to the United Kingdom’. But if ‘the day and time’ never comes, Parliament said nothing further about it. This was wise because, as Lord Nicholls said in the FBU case, the ‘range unexpected happenings is infinite’, a ‘serious flaw… might come to light. An economic crisis might arise. The government might consider it was no longer practicable, or politic’ to continue.

Third, the language of the Act ensures that the UK can change its mind. If ‘exit day’ is never commenced the preparations and arrangements to be made under sections 8 to 12 never come into play because there is never any agreement by the House of Commons of ‘the withdrawal agreement’. Everything in the Act is ‘contingent and prospective’ (to adopt a phrase from insolvency law) upon a withdrawal agreement actually being agreed.

Fourth, the better view is that ‘Parliament has retained ultimate control over the UK’s withdrawal’, and this must include the possibility that ‘exit day’ could be indefinitely delayed. Section 13 says there must be ‘Parliamentary approval of the outcome of negotiations with the EU’. Any drafter of this legislation must have therefore envisaged that Parliament would simply say ‘no’. In any event, revocation would not mean there would never be exit day, because there is always the possibility that article 50 could be triggered again.

Fifth, upon revocation of article 50, exit day could simply be delayed pending a political decision to repeal the Act. In this situation, revocation could not be reasonably considered to frustrate the Act. Just as no referendum can rule the living forever from its grave, the keystone of our constitution is that no Parliament can bind a future Parliament.

Despite these reasons, it does not follow that an Act, though unnecessary, is undesirable. An Act of Parliament could be useful to remove the power of the executive with regard to the timetable of withdrawal and negotiations, and therefore the potential for its abuse. For this reason alone, the discussion of legislation, which Phillipson and Young have highlighted, is a valuable one.

Executive action to revoke article 50

If there is no question of frustration, this means that under the European Union (Notification of Withdrawal) Act 2017 section 1, the Prime Minister can revoke article 50. The popular view in the media appears correct that this is ‘a unilateral act that could be done in minutes by [the Prime Minister] via an email to Donald Tusk’. Section 1 is framed in the style of international law negotiations, which on the pathbreaking analysis of Sir Hersch Lauterpacht QC function like any ordinary contractual dealing. Indeed, the right to revoke an intention to negotiate for a deal (or an invitatio ad offerendum) is codified in the Vienna Convention on Treaties, article 68. Because pausing Brexit has become the majority will of the British public (a fact that seems to compound with demographic change) the orthodox legal position that the executive may revoke article 50 also appears politically sound.

Dr Ewan McGaughey (@ewanmcg) is a senior lecturer at the School of Law, King’s College, London, and a research associate at the Centre for Business Research, University of Cambridge.

(Suggested citation: E. McGaughey, ‘What Is Needed in Our Constitution to Revoke Article 50?’, U.K. Const. L. Blog (2nd Apr. 2019) (available at

3 comments on “Ewan McGaughey: What Is Needed in Our Constitution to Revoke Article 50?

  1. Pingback: Brexit Highlights 1 – 7 April 2019 | Middle Temple Library Blog

  2. Tony
    June 25, 2019

    I agree that executive action alone is sufficient to revoke the Article 50 notification because revocation is governed by international law. If this happened the next question would be the status of the European Union (Withdrawal) Act 2018 [EUWA]. Would the European Communities Act 1972 [ECA] still be automatically repealed by section 1 of the EUWA if “exit day” came to pass even though the UK was still a party to TEU/TFEU due to the revocation?

    Section 2(4) of the ECA states that “any enactment passed or to be passed… shall be construed and have effect subject to the foregoing provisions of this section”. This makes the effect of all future legislation (including the EUWA) subject to the “rights, powers, liabilities, obligations and restrictions from time to time created or arising by or under the Treaties” defined in section 2(1) of the ECA. Therefore section 1 of the EUWA cannot have effect if this would result in the dis-application of EU law because of the primary obligation under TFEU 291(1): “Member States shall adopt all measures of national law necessary to implement legally binding Union acts”.

    This means that section 1 of the EUWA would be dis-applied by section 2(4) of the ECA if the UK was still a party to TEU/TFEU after “exit day”. This would be the case even if the UK government did not amend the definition of “exit day” in section 20(4) of EUWA.

  3. Paul W
    June 26, 2019

    The author states that “.. R (Miller) v Secretary of State for Exiting the EU[2017] UKSC 5, … decided that triggering article 50 risked depriving citizens of rights guaranteed by Acts of Parliament. Deprivation of rights requires a new Act. But revoking article 50 threatens nobody’s statutory rights: it protects them. On that basis alone an Act is not needed.”

    Whilst the ‘deprivation of rights’ argument was the beginning of the Supreme Court’s decision in Miller, it was not the end of it. The Supreme Court held that the Royal prerogative was ousted generally in relation to the UK’s membership of the European Union, not just in relation to withdrawal.

    Some of the Supreme Court’s remarks are as follows. Of course they were directed to the question of the decision to withdraw. But by and large they apply as much to a decision to revoke that withdrawal decision to leave.

    “86. Accordingly, the Royal Prerogative to make and unmake treaties, which operates wholly on the international plane, cannot be exercised in relation to the EU Treaties, at least in the absence of domestic sanction in appropriate statutory form…”

    “82. We cannot accept that a major change to UK constitutional arrangements can be achieved by ministers alone; it must be effected in the only way that the UK constitution recognises, namely by Parliamentary legislation.”

    “88. In addition, there is the fact that the 1972 Act required ministers not to commit the United Kingdom to any new arrangement, whether it increased or decreased the potential volume and extent of EU law, without first being approved by Parliament – by statute in the case of a new EU Treaty and by an approved Order in Council in the case of a treaty ancillary to any existing EU Treaty.”

    “83. More centrally, … section 2 of that Act [ECA 1972] envisages domestic law, and therefore rights of UK citizens, changing as EU law varies, but it does not envisage those rights changing as a result of ministers unilaterally deciding [that the United Kingdom should withdraw from the EU Treaties].”

    Whilst the Supreme Court’s remarks are naturally directed towards a decision to withdraw from the EU, they are equally applicable to revoking such a decision, especially the reference in paragraph 86 to ‘make and unmake treaties’ and paragraph 86 to any arrangement that ‘increased or decreased’ the volume of and extent of EU law.

    At present the UK is committed to leave the EU with the authority of Parliament under the EU (Notification of Withdrawal) Act. Parliament has therefore determined that EU law pursuant to the EU Treaties will cease to apply when the withdrawal takes effect.

    Revocation will reverse that position, so that EU law under the EU Treaties will continue in effect beyond the date that Parliament authorised that it should cease to have effect. That falls within the dicta of paragraphs 86, 82, and 88. The Supreme Court in Miller would seem to demand that a further Act of Parliament be passed to authorise revocation. The Royal Prerogative has been ousted.

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