Blog of the International Journal of Constitutional Law

Legal Uncertainty Surrounding the Approval of the Brexit Agreement

Antonios Kouroutakis, Assistant Professor, IE University

The referendum of June 23rd 2016 and the majority vote in favour of Brexit led British constitutional law into uncharted territories as Paul Craig has accurately said.[1] The constitutional order of the United Kingdom is being overwhelmed by a paradox. Although it is governed by the principle of parliamentary sovereignty rather than by the rule of popular sovereignty, the outcome of the referendum, as an expression of the principle of popular sovereignty, reveals unprecedented legal issues.

The first question raised was whether the executive had the power to activate Article 50 of the Treaty of the European Union (TEU) or whether there is a need to adopt a law according to which the Prime Minister will be empowered to activate Article 50 TEU. The UK Supreme Court resolved that issue [2] holding that the activation of article 50 TEU falls within the power of the legislative body, and therefore a parliamentary law is necessary.[3]

Since the withdrawal procedure under Article 50 TEU is triggered, the question is the following: what is the procedure for approving the possible agreement between the United Kingdom and the Member States of the European Union (henceforth Brexit Agreement)? Does a parliamentary procedure suffice? Or there is need for a new referendum?  And most importantly, in case the UK Parliament – or the popular will in a referendum – rejects the Brexit Agreement, what is the legal effect? Does the rejection of the Brexit Agreement automatically activate a hard Brexit?

Before the official launch of Article 50 TEU and during the parliamentary discussions on the European Union (Notification of Withdrawal) Bill that aimed to confer on the Prime Minister the power to give the notice required under Article 50, the Lords amended the bill adding the following provision:[4]

“Parliamentary approval for the outcome of negotiations with the European Union (1) The Prime Minister may not conclude an agreement with the European Union under Article 50(2) of the Treaty on European Union, on the terms of the United Kingdom’s withdrawal from the European Union, without the approval of both Houses of Parliament. (2) Such approval shall be required before the European Parliament debates and votes on that agreement.”

With this provision, the Lords first clarified the issue of the approval process explicitly granting to the parliament the competence to approve the Brexit Treaty and second they placed this procedure before the conclusion of the approval process from the European Parliament in order to avoid any fait accompli.

But, the House of Commons rejected the amendment “because it [was] not a matter that need[ed] to be dealt with in the Bill.”[5] On the approval process, the Government before the elections, in a white paper published in March 2017 argued that “any new treaty that we agree with the EU will also be subject to the provisions of the Constitutional Reform and Governance Act 2010 before ratification.”[6]

Indeed, the Constitutional Reform and Governance Act regulates this issue and specifically article 20 stipulates the default rule that any international treaty must be submitted to Parliament prior to any ratification.[7] On the other hand, the European Union Law of 2011[8] that provided for the obligation to hold a referendum for new treaties amending of replacing EU Treaties, from a teleological point of view, is not applied given that the agreement on Brexit, in theory, reverses this transfer of powers from the EU back to the UK. Furthermore, article 4 explicitly mentions cases according to which a referendum is necessary.[9]

While prima facie, new legislation on the issue is not necessary, in the case of the replacement of European treaties with a new agreement recognizing the United Kingdom’s remain in the single market, the so-called soft brexit version, like Norway and Switzerland, it can be argued that this kind of agreement will trigger a new referendum.

In particular, Article 9 (1) (i) of European Union Law 2011 expressly states that a new referendum is necessary, if a new treaty that amends or replaces the EU Treaties involves the “conferring on an EU institution or body of power to impose a requirement or obligation on the United Kingdom, or the removal of any limitation on any such power of an EU institution or body.”[10] Having said that, the case of a soft brexit according to which the UK remains the single market but without its participation in the decision-making process, in essence it confers to the European Union institutions the power to impose requirements and obligations to the UK.

As a result, the existing legal framework is far from being clear, and in order to remove legal uncertainty there is a need for legislative intervention that will clearly define the procedure for the approval of a possible agreement between the EU and the UK. Otherwise, the Supreme Court once again will be called upon to resolve the issue.

Regardless the approval and ratification process, another issue, more puzzling is looming. If Parliament – or the majority of the popular will in case of a referendum – rejects the agreement on Brexit, what is the legal effect?[11] Does a rejection automatically mean no agreement and hard brexit? Or does it mean that the whole negotiation shall rewind and repeat? But this difficult equation has another factor. What if the European Parliament rejects the Brexit Agreement?[12]

Article 50 TEU does not provide any guidance on the issue, and given the parallel approval process, both at a national level from the UK institutions and at EU level from the EU Parliament, this issue is not to be solved unilaterally by the constitutional order of the United Kingdom. What makes more sense is the drafting of a pre agreement, during the initial stages of negotiations, to clarify the framework for every eventuality.

Suggested Citation: Antonios Kouroutakis, Legal Uncertainty Surrounding the Approval of the Brexit Agreement, Int’l J. Const. L. Blog, June 28, 2017, at:

[1] Paul Craig, ‘Brexit: A Drama in Six Acts’ (2016) 41 European Law Review 447.

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

[3] Accordingly the European Union (Notification of Withdrawal) Act 2017 was enacted.

[4] European Union (Notification of Withdrawal) Bill] 2017 HL 109 , art 2.

[5] European Union (Notification of Withdrawal) Bill] 2017 HL 111 [1A].

[6] Department for Exiting the European Union “Legislating for the United Kingdom’s withdrawal from the European Union” (CM 9446) March 2017 [1.19].

[7] Constitutional Reform and Governance Act 2010 c 25 art 20. For further discussion on the topic see Paul Craig, ‘Brexit: A Drama in Six Acts’ (2016) 41 European Law Review 447, 460 ff and Menelaos Markakis, Legal Issues Arising from Brexit Referendum: A UK and EU Constitutional Analysis (2017) 45 International Journal of Legal Information 14, 22.

[8] European Union Act 2011 c 12 art 2.

[9] European Union Act 2011 c 12 art 4 (1).

[10] European Union Act 2011 c 12 art 4 (1) (i).

[11] Craig discussed another relevant issue, which is the case of non-agreement after the expiration of the two year sunset clause set in article 50 TEU. See Paul Craig, ‘Brexit: A Drama in Six Acts’ (2016) 41 European Law Review 447.

[12] The last second of Article 50, paragraph 2 provides that “[The Agreement] shall be concluded on behalf of the Union by the Council, acting by a qualified majority, after obtaining the consent of the European Parliament.” See Treaty Functioning the European Union, Article 50 (2).


One response to “Legal Uncertainty Surrounding the Approval of the Brexit Agreement”

  1. Antonios Kouroutakis Avatar
    Antonios Kouroutakis

    As a follow up, on the first issue pertaining the conflict between the Constitutional Reform and Governance Act and the European Union Act, the European Union (Withdrawal) Bill, currently debated, explicitly repeals the European Union Act. See European Union (Withdrawal) Bill, Schedule 9.

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