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Territorial Differentiation in EU Law: Can Scotland and Northern Ireland Remain in the EU and/or the Single Market?

Published online by Cambridge University Press:  08 November 2017

University of East Anglia


In the Brexit referendum of 23 June 2016, voters in England and Wales voted to leave the EU, while in Scotland and Northern Ireland they voted to remain. Following that, there has been a debate about how it would be possible to achieve the continuing presence in the single market of the UK constituent nations that do not want to be taken out against their will. This paper explores two pathways for Scotland and Northern Ireland to remain in the EU and/or the single market. The first entails the achievement of Scottish independence and the reunification of Ireland through democratic referendums. To this effect, the paper reviews the right of secession of those two constituent nations under UK constitutional law. It revisits the debate on the appropriate legal basis regulating Scotland’s future EU accession and discusses the Irish reunification from an EU law perspective. The second pathway explores how it would be possible for Scotland and Northern Ireland to remain in the EU and/or the single market even without seceding from the UK. In order to do that, the paper points to the remarkable flexibility of the EU legal order as evidenced in numerous cases of differentiated application of Union law. The paper shows that the EU possesses the necessary legal instruments to accommodate the divergent aspirations of the UK constituent nations.

© Centre for European Legal Studies, Faculty of Law, University of Cambridge 

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I would like to thank Profs M Cremona, C Kilpatrick, KA Armstrong and the anonymous reviewers for their comments in earlier drafts and Dr C Ní Ghiollarnáth for language editing. Special thanks to Ion Skoutaris Gonzalez for his encouragement. The usual disclaimers apply. An earlier version of this paper was published by the Academy of European Law (EUI) as part of its Working Papers series under the title ‘From Britain and Ireland to Cyprus: Accommodating ‘Divided Islands’ in the EU Political and Legal Order’.


1 In Scotland 62% voted to remain in the EU, and in Northern Ireland 56%. In England, 53% voted to leave and in Wales 52.5%.

3 Ibid.

5 See G Gatehouse, ‘Brexit: Gibralter in talks with Scotland to stay in EU’ (BBC News, 27 June 2016)

6 See Scottish Government, Scotland’s Place in Europe

11 See House of Lords, European Union Committee, Brexit: Devolution, HL Paper 9, para 6,

13 ‘Prime Minister’s letter to Donald Tusk triggering Article 50’ (29 March 2017); see also ‘Prime Minister’s Commons statement on triggering Article 50’ (29 March 2017) See para 14 of the EU Negotiating Directives

14 See above note 11 above, para 7.

16 Such a right is not unilateral. As we shall see in the following section, Schedule 1 of the Northern Ireland Act 1998 provides that a referendum for the reunification of Ireland can only be organised if ‘it appears likely to [the UK Secretary of State] that a majority of those voting would express a wish that Northern Ireland should cease to be part of the United Kingdom and form part of a united Ireland.’

17 The acquis does not apply to almost 40% of Cypriot territory.

18 The people of the Irish Republic should also agree to this in a separate referendum.

19 Imperial Tobacco Limited v The Lord Advocate (Scotland) [2012] UKSC 61, para 15.

20 E Smith and A Young, ‘That’s how it worked in 2014, and how it would have to work again’ (UK Constitutional Law Association, 15 March 2017)

21 Ibid.

22 For an analysis of the debate, see McHarg, A et al (eds), The Scottish Independence Referendum: Constitutional and Political Implications (Oxford University Press, 2016)Google Scholar; Armstrong, KA, ‘The Reach and Resources of European Law in the Scottish Independence Referendum’ in C Closa (ed), Secession from a Member State and Withdrawal from the European Union: Trouble Membership (Cambridge University Press, 2017)Google Scholar.

23 For a view in favour of Holyrood’s powers to organise such a referendum see eg Barber, N, ‘Scottish Independence and the Role of the United Kingdom’ (UK Constitutional Law Association, 11 January 2017)Google Scholar Contra see eg Tomkins, A, ‘The Scottish Parliament and the Independence Referendum’ (UK Consitutional Law Association, 12 January 2017)Google Scholar For an analysis of the legal nature of the Edinburgh Agreement, see Bell, C, ‘The Legal Status of the Edinburgh Agreement’ (Scottish Constitutional Futures Forum, 5 November 2012)Google Scholar

25 Sec 30(2) Scotland Act 1998 provides that ‘Her Majesty may by Order in Council make any modifications’ of the reserved matters ‘which She considers necessary or expedient.’ The Scotland Act 1998 (Modification of Schedule 5) Order 2013.

27 R (on the application of Miller and another) v Secretary of State for Exiting the European Union [2017] UKSC 5, para 146.

28 C Mac Amhlaigh, ‘Scotland Can Veto Brexit (sort of…)’ (Verfassungsblog, 28 June 2016) According to this argument, Westminster would not normally legislate in areas devolved to Scotland without the consent of the Scottish Parliament. This is known as the ‘Sewell Convention’. Since its inception, the scope of the convention has evolved so as to require the consent of the Scottish Parliament, not only where the UK Parliament seeks to legislate in devolved policy areas, but beyond that where a UK bill seeks to vary the legislative competence of the Scottish Parliament or the executive competence of the Scottish Ministers. So, given the way the European Communities Act 1972 (ECA) and EU law in general are embedded in the Scotland Act (see eg sec 29 Scotland Act 1998), ‘a repeal of the ECA to give legal effect to Brexit would trigger the Sewell Convention’.

30 Scottish Government, ‘Amendments to UK Brexit will be proposed’

31 McGarry, J, ‘Asymmetrical Autonomy in the United Kingdom’ in M Weller and K Nobbs (eds), Asymmetric Autonomy and the Settlement of Ethnic Conflicts (University of Pennsylvania Press, 2010), p 156 Google Scholar.

32 Other examples of constitutional provisions that provide for a right of secession include Art 39(1) of the Ethiopian Constitution according to which ‘every nation, nationality or people in Ethiopia shall have the unrestricted right to self determination up to secession’ and; Art 4(2) of the Constitution of the Principality of Liechtenstein according to which ‘[i]ndividual municipalities shall be entitled to secede from the union. The decision on whether to initiate a secession procedure shall be made by a majority of the Liechtenstein citizens eligible to vote who reside there. Secession shall be regulated by a law or, as the case may be, by an international treaty. If secession is regulated by a treaty, a second vote shall be held in the municipality after the treaty negotiations have been concluded.’

33 There is nothing in the Irish Constitution (see text of revised Arts 2, 3) that explicitly states that the Taoiseach is obliged by the Constitution, and the duties of his office, to pursue a United Ireland.

34 H McDonald, ‘Northern Ireland secretary rejects Sinn Féin call for border control’ (The Guardian, 24 June 2016)

35 For the different views on this debate, see S Douglas-Scott, ‘Scotland and the EU: eleventh hour thoughts on a contested subject’ (Verfassunglsblog, 17 September 2014)

36 For a brief analysis, see Hillion, C, ‘EU Enlargement’ in P Craig and G de Búrca, (eds), The Evolution of EU Law, 2nd ed, (Oxford University Press, 2011)Google Scholar; Hillion, C, ‘Accession and Withdrawal in the Law of the European Union’ in A Arnull and D Chalmers (eds), The Oxford Handbook of European Union Law (Oxford University Press, 2015)Google Scholar.

37 Art 49(2) TEU.

38 K Hughes, ‘Brexit transition, Scotland and independence: has a new route opened up?’ (Scottish Centre on European Relations, 28 July 2017)

39 President JM Barroso’s letter of 10 December 2012 to the House of Lords Economic Affairs Committee regarding the status of EU membership for Scotland in the event of independence. In fact, this letter follows almost verbatim a similar position expressed by a previous President of the Commission, R Prodi in 2004. According to it, ‘[w]hen a part of the territory of a member-state ceases to be a part of that state, e.g. because the territory becomes an independent state, the Treaties will no longer apply to that territory. In other words, a newly independent region would, by the fact of its independence, become a third country with respect to the Union and the Treaties would from the day of its independence, not apply anymore …’ If the new country wished them again to apply there would need to be ‘a negotiation on an agreement between the applicant state and the member-states on the conditions of admission and the adjustments to the Treaties which such admission entails. This agreement is subject to ratification by all member-states and the applicant state.’ (President R Prodi to the European Parliament Official Journal of the European Union, C84E/422 (3 April 2004)).

40 See Scottish Government, Scotland’s Future: Your Guide to an Independent Scotland, pp 216224, Google Scholar.

41 Ibid, p 221.

42 See note 38 above.

43 Ibid.

44 K Starmer, ‘No “constructive ambiguity”. Labour will avoid Brexit cliff edge for UK economy’ (The Guardian, 26 August 2017)

45 Commission v Council, C-300/89, EU:C:1991:244.

46 Equally unconvincing from a public international law perspective is the suggestion that Scotland could also be seen as representing the continuing UK membership; A O’Neill ‘England’s difficulty; Scotland’s opportunity’ (Verfassungsblog, 28 June 2016) To this effect, see J Crawford and A Boyle, Opinion: Referendum on the Independence of Scotland – International Law Aspects,

48 The EFTA Member States in the Council are Iceland, Liechtenstein, Norway and Switzerland.

49 Art 56(3) of the EFTA Convention requires a new member of EFTA to ‘apply to become a party to the free trade agreements between the Member States on the one hand and third states, unions of states or international organisations on the other.’ Despite the language, it seems that the legal framework of EFTA is flexible enough to allow Scotland not to ‘sign up to those trade agreements with third countries that would be incompatible with its customs relationship with rUK’, Lock, T, ‘Scotland’s Place in Europe After Brexit: Between a Rock and a Hard Place? A Legal Scoping Exercise’ (2017) 2 European Papers 183, p 190 Google Scholar.

50 For an analysis of the Community law implications of the German reunification see generally C Tomuschat, ‘A United Germany within the European Community’ (1990) 27 Common Market Law Review 415; CWA Timmermans, ‘German Unification and Community Law’ (1990) 27 Common Market Law Review 437. Special Meeting of the European Council, Dublin, 28 April 1990,

51 D Schiek, ‘“Hard Brexit”-How to address the new conundrum for the Island of Ireland?’

52 The relationship of the DDR with the then Community was clarified in the judgment of the Court of Justice in Case 14/74, EU:C:1974:92. In that decision, the Court held that the relevant rules exonerating West Germany from applying the rules of EEC law to German Internal Trade ‘does not have the result of making the German Democratic Republic part of the Community, but only that a special system applies to it as a territory which is not part of the Community’.

54 The European Council agreed the following statement in the minutes to the agreement on the Brexit negotiating guidelines on 29 April 2017: ‘The European Council acknowledges that the Good Friday Agreement expressly provides for an agreed mechanism whereby a united Ireland may be brought about through peaceful and democratic means; and, in this regard, the European Council acknowledges that, in accordance with international law, the entire territory of such a united Ireland would thus be part of the European Union’ European Council, Minutes of Special Meeting of the European Council (Art.50) held on 29 April 2017 (23 June 2017)

55 Art 1 of Protocol No 10 on Cyprus of the Act of Accession 2003 [2003] OJ L236/955.

56 Council Decision 95/1/EC, Euratom, ECSC of the Council of the European Union of 1 January 1995 adjusting the instruments concerning the accession of new Member States to the European Union [1995] OJ L1/1.

57 For a comparative approach of the suspension of the acquis in Northern Cyprus see generally Skoutaris, N, ‘The Status of Northern Cyprus Under EU Law. A Comparative Approach to the Territorial Suspension of the Acquis ’ in D Kochenov (ed), On Bits of Europe Everywhere. Overseas Possessions of the EU Member States in the Legal-Political Context of European Law (Kluwer Law International, 2011)Google Scholar.

58 For a comprehensive analysis of the application of Union law to Overseas Countries and Territories (OCTs) and to Outermost Regions see generally D Kochenov (ed), ibid; Kochenov, D, ‘Substantive Procedural Issues in the Application of European Law in the Overseas Possessions of European Union Member States’ (2008) 17 Michigan State of International Law 195 Google Scholar; Kochenov, DThe Impact of European Citizenship on the Association of the Overseas Countries and Territories within the European Community’ (2009) 36 Legal Issues of Economic Integration 239 Google Scholar; Murray, F, EU and Member State Territories, The Special Relationship under Community Law (Sweet & Maxwell, 2004)Google Scholar; Ziller, J, ‘Flexibility in the Geographical Scope of EU Law: Diversity and Differentiation in the Application of Substantive Law on Member States’ Territories’ in G de Búrca and J Scott (eds), Constitutional Change in the EU: From Uniformity to Flexibility (Hart Publishing, 2000)Google Scholar; Ziller, J, ‘Les collectivités des outre-mer de l’Union européenne’in JY Faberon (ed), L’ Outre-mer Français: La nouvelle donne institutionelle (Documentation Française, 2004)Google Scholar; Ziller, J, ‘L’ Union européene et l’outre-mer’ (2005) 113 Pouvoirs 145 Google Scholar; Ziller, J, ‘The European Union and the Territorial Scope of European Territories’ (2007) 38 Victoria University Wellington Law Review 51 CrossRefGoogle Scholar.

59 The Outermost Regions are: French Guadeloupe, French Guiana, Martinique and Réunion, Saint-Barthélemy, Saint-Martin, the Spanish Canary Islands, and the Portuguese Azores and Madeira. Mayotte became an Outermost Region of the European Union on 1 January 2014, following a 2009 referendum with an overwhelming result in favour of the department status.

60 Art 349 TFEU. In June 2001 the Council adopted two sets of Regulations based on the priorities identified in the Commission Report on the measures to implement Art 299(2) TEC: the Outermost Regions of the European Union, COM(2000) 147, 14 March 2000. The first set of Regulations (Council Regulations 1447/2001, 1448/2001, 1449/2001, 1450/2001, 1451/2001, [2001] OJ L198/1) aimed to take fuller account of the specific nature of the Outermost Regions, under the Structural Funds, as defined in Art 349 TFEU, while the second set (Council Regulations 1452/2001, 1453/2001, 1454/2001, [2001] OJ L198/11) aimed to amend the CAP in order to take greater account of the specific local conditions of the region.

61 For a comprehensive analysis of the application of the acquis in the Outermost Regions, see generally Kochenov, ‘Substantive and Procedural Issues in the Application of European Law in the Overseas Possessions of European Union Member States’, see note 58 above, pp 227–244, 268–286.

62 Act concerning the condition of accession of the Kingdom of Norway, the Republic of Austria, the Republic of Finland and the Kingdom of Sweden and the adjustments to the Treaties on which the European Union is founded [1994] OJ C241/21.

63 Art 355(6)(c) TFEU.

64 Council Regulation (EEC) No 2211/80 of 27 June 1980 on the conclusion of the Agreement on fisheries between the European Economic Community and the Government of Denmark and the Home Government of the Faroe Islands [1980] OJ L226/1. Council Decision 97/126/EC of 6 December 1996 concerning the conclusion of an agreement between the European Community, on the one part, and the Government of Denmark and the Home Government of the Faroe Islands, on the other [1997] OJ L53/1.

65 The UK has 12 OCTs: Anguilla, Cayman Islands, Falkland Islands, South Georgia and the South Sandwich Islands, Montserrat, Pitcairn, Saint Helena and the Dependencies, British Antarctic Territory, British Indian Ocean Territory, Turks and Caicos Islands, British Virgin Islands, and Bermuda (Bermuda, although formally an OCT listed in Annex II, does not benefit from the EU-OCT Association); France has 5 OCTs: New Caledonia and Dependencies, French Polynesia, French Southern and Antarctic Territories, Wallis and Futuna Islands (known collectively as ‘Territoires d’outre mer’) and Saint Pierre and Miquelon; the Netherlands has 2: Aruba and the Netherlands Antilles (Bonaire, Curaçao Saba, Sint Eustatius and Sint Maarten); and Denmark: Greenland.

66 Arts 198, 202, 199(5) TFEU.

67 Art 200(1), (3), (5) TFEU.

68 Art 355(2) TFEU.

69 See Eman and Sevinger v College van Burgemeester en Wethouders van Den Haag, C-300/04, EU:C:2006:545.

70 Art 3 Council Regulation (EEC) No 2913/92 of 12 October 1992 establishing the Community Customs Code [1992] OJ L302/1; Art 6 Council Directive 2006/112/EC of 28 November 2006 on the common system of value added tax, [2006] OJ L347/1.

71 Treaty Amending, With Regard to Greenland, the Treaties Establishing the European Communities, [1985] OJ L29/1; Weiss, F, ‘Greenland’s Withdrawal from the European Communities’ (1985) 10 European Law Review 173 Google Scholar.

72 See for instance T Lock, ‘A European Future for Scotland?’ (Verfassungsblog, 26 June 2016); A Ramsay, ‘A reverse Greenland: the EU should let Scotland stay’ (openDemocracyUK, 24 June 2016)

73 See note 6 above, para 118.

74 Doherty, B et al, Northern Ireland and Brexit: The European Economic Area Option (European Policy Centre, 7 April 2017)Google Scholar Discussion Paper,

75 Protocol 40 on Svalbard of the Agreement on the European Economic Area [1994] OJ L1/208.

76 For an analysis of the EU status of the Faroe Islands, see J Hartmann, ‘The Faroe Islands: Possible Lessons for Scotland in a New Post-Brexit Devolution Settlement’ Edinburgh Law Review, forthcoming,

77 The government’s negotiating objectives for exiting the EU: PM speech, 17 January 2017,

78 The Common Travel Area (CTA) is a special travel zone between the Republic of Ireland and the UK, Isle of Man and Channel Islands. It dates back to the establishment of the Irish Free State in 1922. Nationals of CTA countries can travel freely within the CTA without being subject to passport controls.

79 See note 55 above.

80 Council Regulation (EC) No 866/2004 of 29 April 2004 on a regime under Art 2 Protocol 10 to the Act of Accession [2004] OJ L206/51. For a comprehensive analysis of the Green Line Regulation regime see Skoutaris, N, ‘The application of the acquis communautaire in the areas not under the effective control of the Republic of Cyprus: The Green Line Regulation45 Common Market Law Review (2008) 727 Google Scholar.

81 See UK Government Position Paper, note 15 above, para 42. For an analysis see N Skoutaris, ‘Footnotes in Ireland’

82 Art 2(1) Green Line Regulation

83 Art 2(2) Green Line Regulation.

84 McGuiness, T and Gower, M, The Common Travel Area and the special status of Irish nationals in UK law (House of Commons Library, 9 June 2017)Google Scholar Briefing Paper 7661, p 18.

85 The analogy between the post-Brexit situation in the Irish border and the territorial border between England and Scotland if the latter remains in the single market were also underlined by the Scottish Government. In their 2016 blueprint on Scotland’s Place in Europe (see note 6 above) they suggested that whatever instruments are used for the Northern Ireland/Republic of Ireland border should be applied mutatis mutandis between Scotland and England.

86 Art 4(5) Green Line Regulation; Commission Decision 2004/604/EC of 7 July 2004 on the authorisation of the Turkish Cypriot Chamber of Commerce according to Article 4(5) of Council Regulation (EC) No 866/2004, [2004] OJ L272/12.

87 Art 4(2) Green Line Regulation.

88 Council Regulation (EEC) No 2913/92 establishing the Union Customs Code [1992] OJ L302/1. A similar arrangement applies to goods originating in Northern Cyprus, Art 4(2) Green Line Regulation.

89 See notes 6, 74 above.

90 See, for instance, note 6 above, para 163.

91 E Posner and T Ginsburg, ‘Subconstitutionalism’ (Law School, University of Chicago, 2010) John M Olin Law and Economics Working Paper 507, See M Elliott, ‘A “blatant power grab”? The Scottish Government on the EU (Withdrawal) Bill’ (Public Law for Everyone, 10 August 2017)

92 I would like to thank Prof Cremona for pointing this out to me.

93 Council of the European Union, Seville European Council 21 and 22 June 2002, Presidency conclusions (13463/02), para 24.

94 Art 15 TEU.

95 For different models of representation at the various institutions see Skoutaris, NThe Role of Sub-State Entities in the EU Decision-Making Processes: A Comparative Constitutional Law Approach’ in E Cloots et al (eds), Federalism in the European Union (Hart Publishing, 2012)Google Scholar.

96 For some suggestions of how this can happen see B O’Leary ‘Detoxifying the UK’s exit from the EU: a multi-national compromise is possible’

97 Seville European Council conclusions (see note 93 above), para 24.

98 Costa v ENEL, 6/64, EU:C:1964:66. Internationale Handelsgesellschaft mbH v Einfuhr- und Vorratsstelle für Getreide und Futtermittel, 11/70, EU:C:1970:114; Commission v Luxembourg, C-473/93, EU:C:1996:263.

99 Germany (Art 23 German Basic Law) and Italy (Art 11 Italian Constitution) have interpreted their respective constitutional provisions, relating to the EU or international relations, as embodying the supremacy of EU law by a ‘material change’ of the constitution. France (Arts 54, 55 French Constitution) requires a formal change of the specific constitutional provisions before ratifying a Treaty that would otherwise entail obligations that are not compatible with those provisions. Art 29(5) of the Irish Constitution has expressly incorporated the principle of supremacy to the Constitution.

100 Scotland Act 1998, sec 29(2)(d); Northern Ireland Act 1998, sec 24.

101 Commission v Spain, C-107/96, EU:C:1997:286; Commission v Belgium, C-323/97, EU:C:1998:347.

102 Letter from David Davis, note 7 above.

103 K Hayward, ‘The origins of the Irish border’