public law,

A symphony of parliamentary sovereignty

By Thomas Yeon Jan 21, 2019

– Case note: Case C-621/18 Wightman v Secretary of State for Exiting the European Union

Since the Supreme Court’s (“SC”) landmark judgement in R (on the application of Gina Miller) v Secretary of State for Exiting the European Union,1 the legal position and powers of the Westminster Parliament have been at the epicentre of the Brexit legal conundrum. The recent preliminary ruling given by the European Court of Wightman v Secretary of State for Exiting the European Union2 has added an extra layer of complexity to it by holding that te Parliament can unilaterally revoke the notification to withdraw from the European Union (“EU”) under Article 50 of the Treaty of Lisbon (“TEU”). Agreeing with Advocate General Sánchez-Bordona’s (“AG”) opinion,3 the ECJ held that certain constitutional requirements have to be satisfied for a member state to revoke the notification unilaterally. This Note analyses the AG’s opinion and ECJ’s judgement, suggesting that it is a prudent manifestation of the doctrine of parliamentary sovereignty. It will also briefly examine the constitutional implications of the judgement on the Brexit process in terms of any requirements for revocation. It will be argued that Wightman offers, in line with Miller, a second opportunity to shape and influence the Brexit process.

Advocate-General’s opinion and the European Court of Justice’s ruling

To begin with, the AG recognised that the right of a State to be no longer bound (withdrawal or denunciation) by a treaty is “a manifestation of that State’s sovereignty.”4 By corollary of principle, the unilateral nature of withdrawal is “conducive to the possibility of unilaterally revoking the notification of that decision;” unilateral revocation is also “a manifestation of the sovereignty of the departing Member State.”5 The intention of the sovereign state is, however, “not definitive and may change.”6 Any claims of such change, and therefore any revocation of the notification of withdrawal, must be expressed “in accordance with… [the sovereign state’s] constitutional requirements.”7 This may be manifested in, for example, “a political change that gives rise to a change in the will of the departing State…“8 This shows that the credibility of the notification of withdrawal is heavily dependent on its constitutional basis. Once any intervening political intervention undermines the credibility of the original notification, the parliamentary intention is also expected to change in order to reflect the latest public opinions.

The AG further strengthened the case for revocability when interpreting Article teleologically. He recognised that Article 50(1) is not a “fossilised concept,” and it respects “the national identities of the member states.”9 It also allows “a change in the sovereign will of the Member State…in order to halt a process of withdrawal from the EU which the Member State has decided to reverse.”10 When the public opinions and parliamentary intentions within the Member State do not evince a clear position, the doctrine of favour socieatias may be considered as a key element in reaching a solution which is the “most consonant with the survival…of the Union.”11 This is largely in line with the TEU’s objective of achieving “an ever closer union among the peoples of Europe.”12 This is a careful delineation of the position of the EU regarding political uncertainty in a Member State, as a teleological interpretation of Article 50 was not considered as strictly necessary and should only be considered if the Government cannot advance a credible stance in favour of withdrawal. Furthermore, it should be noted that the fundamental rights enjoyed by nationals of the departing Member State as EU citizens also play a significant role in favouring a teleological interpretation of Article 50 - that revocation is possible unless the Member State’s intention of departure is crystal clear. This reflects the majority of Miller in stating that any frustration of citizens’ rights as an EU citizen can only be done by parliamentary legislation.

The ECJ’s ruling is generally consistent with the AG”s opinion, emphasising the special status of the TEU and the constitutional character of the EU.13 The ECJ also explored the constitutional requirements of withdrawal. In the following sections, the ECJ’s judgement and its implications will be analysed. It will be argued that the judgement represents prudent respect for parliamentary sovereignty in the United Kingdom, and successfully protects the integrity of Article 50, despite any possible doubts over a teleological approach to interpreting it.

Analysis of the European Court of Justice’s judgement

The question posed to the ECJ was “where, in accordance with Article 50 [TEU], a Member State has notified by the European Council of its intention to withdraw from the European Union, does EU law permit that notice to be revoked unilaterally by the notifying Member State; and if so, subject to what conditions and with what effect relative to the Member State remaining within the European Union?”

Interpretation of EU law (in particular, Article 50)

The ECJ stated that when interpreting a provision of EU law, account should be taken “not only of its wording and the objectives it pursues, but also of its context and the provisions…as a whole.”14 From the outset, it is clear that the court is not limiting itself to the meaning of Article 50 itself, but adopting a teleological approach in attempting to unpack the meaning of the provisions in question. The emphasis on the need to consider the constitutional structure and purpose of the EU as a whole15 reflect what Eeckhout and Frantziou noted a “constitutionalist approach,” which is an opportunity to “affirm that the structures [of EU] have come to constitute a new mode of post-State organisation, premised on cooperation, genuine respect for common values and fundamental rights, and a supranational citizenship.”16 The revocability of the notification of withdrawal is thus not only a question surrounding the Parliament’s political will, but also the need to maintain the integrity and pursuit of objectives of the EU. Whilst a teleological approach may be criticised as giving excessive weight to the objective of European integration in the status of Article 50, it is submitted that such approach is justified as Article 50 is a key component in shaping the composition of EU membership under the TEU. To adopt a literal interpretation of Article 50 would ignore the political realities which public law responds to.

The intention of a departing Member State and the associated rights stripping implications

Having firmly established a teleological approach as its basis of approaching the question, the ECJ agreed with the AG’s opinion that the intention of a departing Member State is “neither definitive nor irrevocable.”17 Moreover, it was noted that the two objectives pursued by Article 50 are (i) “enshrining the sovereign right of a Member  State to withdraw from the EU” and (ii) “establishing a procedure to enable such a withdrawal to take place in an orderly fashion.”18 At this point, it is clear that Article 50 is not merely a matter of facilitating an expedient exit for a departing Member State, but more importantly, to respect the voluntary and flexible will of it. The sovereign will of the departing State is the most significant player in the Article 50 process. Given the absence of expression provision in EU law governing the revocation of notification to withdraw, the revocation should be “subject to the rules laid down in Article 50(1) TEU for the withdrawal itself…it may be decided upon unilaterally, in accordance with the constitutional requirements of the State concerned.” Revocation is, in essence, a “sovereign decision” by the State to retain its status as a Member State of the EU; the status is neither suspended nor altered by that notification.19

The ECJ then moved to consider implications of withdrawal. The decision to withdraw is “liable to have a considerable impact on the rights of all Union citizens, including, inter alia, their right for free movement, as regards both nationals of the Member State concerned…“20 Forcing a Member State to leave after it has triggered the Article 50 process, despite a wish to remain “as expressed through its democratic process in accordance with its constitutional requirements,” would be “inconsistent with the [TEU’s] purpose of creating an ever closer union…“21 The intention of the Parliament will always have the final say in determining whether United Kingdom shall remain a Member State of the EU. This also reflects the origins and intention of Article 50, which in its final draft upheld “the voluntary and unilateral nature of the withdrawal decision.”22

Constitutional requirements

Building on the AG’s recognition that any revocation must respect “national constitutional requirements,”23 the ECJ noted that any revocation must be made in an “unequivocal and unconditional manner….after the Member State concerned has taken the revocation decision in accordance with its constitutional requirements.”24 In the United Kingdom, given the judgement in Miller, this would suggest that the “constitutional requirement” in question would be passing primary legislation in the House of Commons revoking the notification of withdrawal as made under the European Union (Notification of Withdrawal) Act 2017. Noting that the sovereign State holds the final decision to revoke the notification to withdraw, the ECJ also correctly noted that any requirement of unanimous approval by the European Council would “transform a unilateral sovereign right into a conditional right subject to an approval procedure.”25 This also, prudently, confers the maximum respect for the Member State in deciding on revocation. Whilst revocation has to be made in accordance with its constitutional requirements and must be made in an “unequivocal and unconditional manner” (presumably meaning that the revocation should reflect popular will), it is the sovereign State alone that can construct the validity and credibility of the revocation. The European Council would have no democratic legitimacy in deciding on the revocation decision.

Implications of the Court’s judgement: the relationship between the European Union and the United Kingdom and parliamentary sovereignty

The unique status of this preliminary ruling is that it is also a matter of political importance and urgency. Whilst constitutional law litigation (especially in the field of human rights) may be seen as predominantly a matter of upholding principles and values, it is clear that the preliminary ruling is primarily aimed at providing an alternative gateway for the Government out of the Brexit conundrum. As the AG accurately noted, the Wightman litigation is “not merely a jurisprudential issue,”26 and the legal consequences of Brexit are drawing “inexorably closer.”27

Parliament’s position as delineated under Article 5

First and foremost, the judgement affirms the centrality of Article 50 in all questions regarding the notification of withdrawal and its revocation. As the Article concerns the structure and composition of the EU itself, any interpretation would “affect the Union’s very identity as a constitutional order committed to the values laid down in Article 2 TEU.”28 The constitutionalist reading adopted by the court reflects a cardinal principle underpinning the relationship between the EU and its Member States: the division of competence.29 The judgement resoundingly puts the competence to decide on revocation firmly in the hands of the Parliament. The Parliament is and will always be in control of the Brexit process in terms of the continuation of negotiations and any decision to revoke its withdrawal notification.

The judgement also reflects the overarching necessity to respect the Member State’’s constitutional process. Following Eeckhout and Frantziou’s analysis of a “constitutionalist reading,” the judgement affords prudent respect to the United Kingdom’s uncodified constitution as “a form of constitutional organisation inherently susceptible to change through politics.”30 Moreover, one must not ignore the distinction between the decision to withdraw (Article 50(1)) and the notification of the decision (Article 50(2)). It would be unrealistic to draw any formalistic distinction between them31 as a change in political realities (e.g. a shift of popular will under Article 50(1) to remain in the EU) would necessarily, as analysed above, undermine the credibility and legitimacy of the notification to withdraw (Article 50(2)). The validity of such change can, however, only be expressed by the Parliament in an unequivocal and unconditional manner.

The constitutional requirements of Article 50: a symmetry with Miller?

Under section 13(1)(b) of the European Union (Withdrawal) Act 2018 (“EUWA”), the House of Commons must approve a withdrawal agreement before the agreement can be considered as ratified. This provides for the implementation of the intention to leave the EU.32 Nowhere it is suggested that the Parliament’s intention before ratifying any withdrawal agreement must be fixed. Following the ECJ’s reasoning, a corollary of the Member State’s sovereign right to submit the notification to withdraw would be its sovereign right to revoke the notification. In terms of substance, the revocation decision has to be made in accordance with its constitutional requirements.33

Given the 2018 Act provides for the implementation to withdraw, revoking the notification as submitted under Article 50 would necessarily strip the Members of Parliament off their rights to implement the withdrawal decision. To revoke using prerogative power, however, would render both the withdrawal agreement and any future framework between the EU and UK otiose.34 This is because the Parliament will no longer be able to approve such instruments, once agreed. In both the AG’s opinion and the ECJ’s ruling, it is clear that the relationship between the criteria for triggering and revoking Article 50 is reciprocal: both triggering and revoking Article 50 must conform to the constitutional requirements of the Member State in question - in this case, the constitutional requirements of UK itself. At this point, the shadow of Miller flickers before us: the royal prerogative may not be exercised in a way that frustrates the intention of the Parliament as expressed in a statute.35 The Prime Minister would not be able to use the prerogative in a way that frustrates the Parliament’s intention of implementing the decision to withdraw from the EU, as evinced by the EUWA 2018.

Last but not the least, Phillipson and Young suggested that given the ECJ’s emphasis on reciprocity and the need to ensure the democratic legitimacy of revocation, the insertion of an option for a referendum under section 13 of EUWA 2018 would not be sufficient. This is an accurate observation of the essence of the Miller judgement, as the provision of a referendum option does not entail sufficient credibility for revocation. Even if a second referendum opted for remaining in the EU, the lack of fresh legislation would mean that, based on Miller, the “constitutional requirements” for revoking the notification would not be satisfied, and thus any attempt to revoke the notification via non-legislative means would be unconstitutional.


The Wightman preliminary ruling authoritatively confirms that the power to revoke the notification of withdrawal is vested solely in the hands of the Parliament. Forming a conclusive symmetry with Miller, it supplied a clear direction and the respective constitutional requirements for the Government to consider if it considers revocation should become a real option. The manifestation of parliamentary sovereignty shows at, at the end of the day, the status of the UK as a Member State of the EU is not affected - it still has full competence to decide whether to continue the negotiations or revoke its notification of withdrawal. The teleological approach to interpreting Article 50 has also provided a clear and definitive guide in approaching the question of withdrawing from the EU: the status of the UK as a Member State of the EU contributes to the composition of the EU constitutional structure, insofar as it has not left the EU yet. Ultimately, the decision to stay as a Member State of the EU or leave it, under the Article 50 framework, is a matter for and only for the Parliament to decide: a manifestation of parliamentary sovereignty.

[1] [2017] UKSC 5.

[2] Case C-621/18 Wightman and another v Secretary for Exiting the European Union [2018] 12 WLUK 94.

[3] Case C-621/18 Wightman and another v Secretary for Exiting the European Union [2018] 12 WLUK 94, Opinion of AG Sánchez-Bordona.

[4] Ibid [93].

[5] Ibid [94].

[6] Ibid [100].

[7] Ibid [104].

[8] Ibid [107].

[9] Ibid [131].

[10] Ibid [132].

[11] Ibid [134].

[12] Article 1 TEU.

[13] (n 3) [44].

[14] Ibid [47].

[15] (n 14).

[16] P Eeckhout and E Frantziou, “Brexit and Article 50 TEU: a constitutionalist reading” (2017) 54 Common Market Law Review 695, 696-697.

[17] (n 3) [49]. The AG made a similar suggestion in his opinion, at [99]-[102].

[18] Ibid [56].

[19] Ibid [59].

[20] Ibid [64].

[21] Ibid [67].

[22] Ibid [68].

[23] (n 4) [144].

[24] (n 3) [74].

[25] Ibid [72].

[26] (n 4) [41].

[27] Ibid [40].

[28] (n 17) 698.

[29] Ibid 702.

[30] Ibid 710.

[31] G Phillipson, “A dive into deep constitutional waters: Article 50, the Prerogative and Parliament” (2016) 79(6) Modern Law Review 1064, 1064-1069.

[32] G Phillipson and A L Young, “Wightman: What would be the UK’s constitutional requirements to revoke Article 50?” UK Constitutional Law Blog (10 December 2018): (last accessed 14 January 2019)

[33] (n 3) [75].

[34] (n 33).

[35] (n 1) [51].

Article by Thomas Yeon
PCLL Candidate (HKU)'2020 and Public Law Notes Editor of the LSE Law Review Summer Board 2019