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Legal Issues Arising from the Brexit Referendum: A UK and EU Constitutional Analysis

  • Menelaos Markakis

The dust has not yet settled after the referendum on Britain's relationship with the EU, which took place on 23 June 2016. UK voted to leave the EU by 51.9% to 48.1%, which is a winning margin of almost 1.3 million votes. However, it is not yet clear what ‘Brexit’ means or how it will come about – legally and constitutionally. This article seeks to answer the latter question from the standpoint of UK and EU law. The discussion begins with the domestic process before beginning the initial withdrawal negotiations, which is governed by UK constitutional law. The focus then shifts to the process of withdrawing from the EU, which is set out in Article 50 TEU. This article further examines whether ‘Brexit’ can be stopped once Article 50 has been triggered. The penultimate section of the article looks at the legal nature and substantive content of the agreements that might be concluded between the UK and the EU if ‘Brexit’ were to become a reality. The final section of the article examines the UK rules on ratification of such international agreements.

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1 See e.g. ‘EU Referendum Results’ <> accessed 18 August 2016. For a lucid account of the referendum debates, see Arnull, Anthony, ‘Broken Bats’ (2016) 41 European Law Review 473; ‘Set of Terms for Brexit Needs to Be Decided: Professor Weatherill’ (CNN-News18, 3 July 2016) <> accessed 21 August 2016. On the ill-fated UK's new settlement with the EU, see Amtenbrink, Fabian, Karatzia, Anastasia and Repasi, René, Renegotiation by the United Kingdom of its Constitutional Relationship with the European Union: Issues Related to the Economic Governance (Study for the AFCO Committee, Publications Office 2016); Paul Craig and Menelaos Markakis, ‘The Euro Area, its Regulation, and Impact on Non-Euro Member States’ in Panos Koutrakos and Jukka Snell (eds), Research Handbook on the Law of the EU's Internal Market (Edward Elgar, forthcoming).

2 Craig, Paul, ‘Brexit: A Drama in Six Acts’ (2016) 41 European Law Review 447, 462. On the royal prerogative, see e.g. Leyland, Peter, The Constitution of the United Kingdom: A Contextual Analysis (3rd ed., Hart Publishing 2016) 32, 8790 .

3 Laker Airways Ltd v Department of Trade [1977] Q.B. 643, 705 (Lord Denning) (concerning a discretionary power arising under a treaty).

4 Ibid. 705.

5 Case of Proclamations (1611) 12 Co. Rep 74, [75].

6 ibid [76].

7 See Select Committee on the Constitution, The Invoking of Article 50 (fourth report) (2016–17, HL 44) chapter 2, which argues that it would be constitutionally inappropriate to trigger Article 50 without consulting Parliament. See also Mark Elliott and Stephen Tierney, ‘The House of Lords Constitution Committee Reports on Article 50’ <> accessed 14 September 2016.

8 I am grateful to Professor Stephen Weatherill for this last point.

9 Alison Young, ‘Brexit, Article 50 and the “Joys” of a Flexible, Evolving, Un-codified Constitution’ in Pavlos Eleftheriadis (ed.) and others, ‘Legal Aspects of Withdrawal from the EU: A Briefing Note’ (14 July 2016) <> accessed 3 August 2016, 20–24.

10 Nick Barber, Tom Hickman and Jeff King, ‘Pulling the Article 50 “Trigger”: Parliament's Indispensable Role’ (U.K. Const. L. Blog, 27 June 2016) <> accessed 3 August 2016.

11 ibid.

12 Attorney General v De Keyser's Royal Hotel Ltd [1920] A.C. 508, 526 (Lord Dunedin).

13 Ibid. 526.

14 Ibid. 528.

15 R. v. Secretary of State for the Home Department, ex p. Fire Brigades Union [1995] 2 A.C. 513.

16 Ibid. 552.

17 Paul Craig (n 2) 463.

18 Ibid. 463.

19 Ibid. 463.

20 Ibid.463.

21 Ibid.463.

22 Alison Young (n 9) 21.

23 Paul Craig (n 2) 462; Alison Young (n 9) 21–23.

24 Dicey, Albert Venn, An Introduction to the Study of the Law of the Constitution (10th ed., Macmillan 1959) 24; Peter Leyland (n 2) 32–42.

25 Alison Young (n 9) 21.

26 Select Committee on the Constitution (n 7) 10.

27 Ibid. 12.

28 European Parliamentary Research Service, ‘Article 50 TEU: Withdrawal of a Member State from the EU’ (February 2016) <> accessed 17 August 2016, 3.

29 Article 238(3)(b) TFEU.

30 Article 231 TFEU; Rule 168(2) of the European Parliament's Rules of Procedure.

31 See, e.g., Articles 10(2) and 14(2) TEU. For a different opinion, see Łazowski, Adam, ‘Withdrawal from the European Union and Alternatives to Membership’ (2012) 37 European Law Review 523, 528, who argues that ‘[a]lthough art.50 TEU is silent on this, it seems reasonable to expect that the same rule will apply to the elected members of the European Parliament from the departing country’.

32 Rieder, Clemens M., ‘The Withdrawal Clause of the Lisbon Treaty in the Light of the EU Citizenship: Between Disintegration and Integration’ (2013–14) 37 Fordham International Law Journal 147, 159.

33 Article 20(2)(b) TFEU.

34 Clemens M. Rieder (n 32) 159.

35 See generally Virginia Mantouvalou, ‘EU Citizens as Bargaining Chips’ (U.K. Const. L. Blog, 14 July 2016) <> accessed 19 August 2016.

36 Darren Harvey, ‘What Role for the European Parliament Under Article 50?’ (EU Law Analysis Blog, 14 July 2016) <> accessed 3 August 2016.

37 European Parliamentary Research Service (n 28) 4.

38 See also Adam Łazowski (n 31) 530–31.

39 Paul Craig (n 2) 464.

40 Ibid. 464.

41 Ibid. 463–64.

42 Ibid. 465.

43 Ibid. 464.

44 See also European Union Committee, The Process of Withdrawing from the European Union (eleventh report) (2015–16, HL 138) chapter 2.

45 See, e.g., Jake Rylatt, ‘The Irrevocability of an Article 50 Notification: Lex Specialis and the Irrelevance of the Purported Customary Right to Unilaterally Revoke’ (U.K. Const. L. Blog, 27 July 2016) <> accessed 14 September 2016.

46 I am most grateful to Professor Stephen Weatherill for his comments on this line of argument.

47 I am grateful to Professor Stephen Weatherill for this point.

48 A constitutional statute is ‘one which (a) conditions the legal relationship between citizen and state in some general, overarching manner, or (b) enlarges or diminishes the scope of what we would now regard as fundamental constitutional rights’: Thoburn v Sunderland City Council [2002] EWHC 195 (Admin); [2003] Q.B. 151 (DC) [62]. On constitutional statutes, see e.g. Barczentewicz, Mikołaj, ‘“Constitutional Statutes” Still Alive?’ (2014) 130 Law Quarterly Review 557; Craig, Paul, ‘Constitutionalising Constitutional Law: HS2’ (2014) 29 Public Law 373.

49 I am grateful to Professor Paul Craig for this astute observation.

50 I am grateful to Professor Paul Craig for this comment.

51 Select Committee on the Constitution (n 7) 5.

52 Paul Craig (n 2) 465. For a view on this issue, see René Repasi and Anastasia Karatzia, ‘The Future Constitutional Relationship of the UK with the EU with a Special View to Economic Governance and the Internal Market’ (The Future Constitutional Relationship of the United Kingdom with the European Union workshop, EP Committee on Constitutional Affairs, Brussels, 5 September 2016) <> accessed 13 September 2016: ‘The withdrawal agreement has to cover aspects of the future relationship between the UK and the Union. Otherwise the withdrawal agreement could not take account of the framework relating to this future relationship. A position stating first the withdrawal and then negotiations about the future relationship appears against this background at least questionable.’ On the withdrawal agreement, see further Dashwood, Alan, ‘After the Deluge’ (2016) 41 European Law Review 469; De Witte, Bruno, ‘Near-Membership, Partial-Membership and the EU Constitution’ (2016) 41 European Law Review 471; Pavlos Eleftheriadis, ‘A New Referendum is a Constitutional Requirement’ in Pavlos Eleftheriadis (ed.) and others, ‘Legal Aspects of Withdrawal from the EU: A Briefing Note’ (14 July 2016) <> accessed 3 August 2016, 25–28.

53 Articles 216–219 TFEU, esp. Article 218 TFEU.

54 Article 218(1) TFEU; Article 207(3)–(5) TFEU.

55 See also European Parliamentary Research Service (n 28) 4–5. Further, René Repasi and Anastasia Karatzia (n 52) argue that: ‘If such future relationship is to be determined on the basis of tailor-made arrangements, Article 50 TEU won't serve anymore as a legal basis but Article 207 TFEU on the common commercial policy has to be exercised’.

56 Fabian Amtenbrink, Anastasia Karatzia and René Repasi, ‘What Happens Next? Legal Consequences of the Brexit Vote’ (24 June 2016) <> accessed 4 August 2016. The CJEU will soon decide whether the EU-Singapore Free Trade Agreement constitutes a mixed agreement – a decision which might have implications for the rules governing the conclusion of any future EU-UK comprehensive trade agreement (Opinion 2/15). For the fate of existing mixed agreements after ‘Brexit’, see Koutrakos, Panos, ‘Negotiating International Trade Treaties After Brexit’ (2016) 41 European Law Review 475.

57 Adam Łazowski (n 31) 529–30.

58 See generally Barnard, Catherine, ‘The Practicalities of Leaving the EU’ (2016) 41 European Law Review 484.

59 Steve Peers, ‘What Next After the UK Vote to Leave the EU?’ (EU Law Analysis Blog, 24 June 2016) <> accessed 3 August 2016.

60 Ibid.

61 See generally Moloney, Niamh, ‘Financial Services, the EU, and Brexit: An Uncertain Future for the City?’ (2016) 17 German Law Journal Brexit Special Supplement 75; René Repasi and Anastasia Karatzia (n 52).

62 John Armour, ‘Brexit to the EEA: What Would It Mean?’ in in Pavlos Eleftheriadis (ed.) and others, ‘Legal Aspects of Withdrawal from the EU: A Briefing Note’ (14 July 2016) <> accessed 3 August 2016, 33.

63 Ibid. 34.

64 Ibid. 34.

65 Follow the discussion by Robert Peston of ITV News: (16 August 2016) <> accessed 17 August 2016.

66 Constitutional Reform and Governance Act 2010, s 20.

67 Constitutional Reform and Governance Act 2010, Explanatory Memorandum, para.144.

68 Constitutional Reform and Governance Act 2010, s 23(1)(c).

69 European Union Act 2011, s 2.

70 See, e.g., Paul Craig (n 2) 466.

71 Pavlos Eleftheriadis (n 52) 25–29.

72 Paul Craig (n 2) 467.

73 Ibid. 467.

74 Ibid. 467.

* DPhil Candidate in Law, University of Oxford; Researcher, Erasmus University of Rotterdam. I am immensely grateful to Professor Paul Craig and Professor Stephen Weatherill for their comments on an earlier draft. All remaining errors are my own.

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