A policy department of the European Parliament has published a study on the legal implications of Brexit.

The study addresses the implications of several scenarios of the UK withdrawing from the EU in relation to the EU Customs Union, the Internal Market law for goods and services (excluding financial services), and on consumer protection law, identifying the main cross-cutting challenges that have to be addressed irrespective of the policy choices that will be made in due course.

In relation to the forward-looking agreement which deals with the future relationship between the UK and the EU the study notes, among other things, the following:

• comprehensive free trade agreements are considered mixed agreements, thereby requiring ratification by all Member States in accordance with their respective constitutional requirements; and
• the EU Treaties and protocols may also need to be amended in order to take stock of the post-Brexit reality.

In terms of the withdrawal agreement the study notes, among other things, that:

• the withdrawal agreement does not need to be ratified by the national Parliaments of Member States;
• the Council of the EU (Council) needs to obtain the consent of the European Parliament, which requires a simple majority of at least one third of the total number of MEPs. Throughout the Brexit negotiations, the European Commission and the Council have to inform the committee responsible regularly and fully on the progress of the negotiations, if necessary on a confidential basis. At any stage of the negotiations, the European Parliament may adopt recommendations and require that these be taken into account before the conclusion of the withdrawal agreement. When the negotiations are completed, the draft withdrawal agreement must be submitted to the European Parliament;
• there is disagreement between commentators as to whether British MEPs may still participate in the vote on the withdrawal agreement in the European Parliament once the agreement is concluded. Article 50 is silent on this issue, but it is argued in the study that British MEPs will be participating in the vote as they represent the citizens of the EU and not just their hone Member State; and
• there is some ambiguity concerning the UK constitutional requirements on the role of the UK Parliament in the process leading to Brexit. Though it was clarified by the UK courts in the case of Miller that the UK Parliament’s approval was required before triggering Article 50, it is not yet clear what would be required for the ratification of the withdrawal agreement once it is concluded. The Constitutional Reform and Governance Act 2010 requires that the agreement be submitted for review by the UK Parliament, acting separately, under the negative resolution procedure. However, the regime under this Act may not be held to be applicable if some greater Parliamentary involvement is required, with some commentators arguing that an Act of Parliament may be needed;

View Legal implications of Brexit: Customs Union, Internal Market Acquis for Goods and Services, Consumer Protection Law, Public Procurement, 9 August 2017