In this note we look at the procedure for the UK to withdraw from the EU under EU law. We do not focus in detail on the UK legal proceedings concerning the power of the UK Government to give notice under Article 50 of the Treaty on European Union (“TEU”), otherwise known as the Lisbon Treaty.

Executive summary

• The UK needs to trigger Article 50 TEU to commence the process of exiting the EU
• The EU might be able to veto the withdrawal agreement but not the UK’s exit
• Absent Treaty change, there is no legal mechanism for the UK to exit immediately
• Whether the withdrawal agreement requires ratification depends on its contents

The withdrawal process
The requirements governing the UK’s withdrawal from the EU are contained in Article 50 TEU. This is understood currently to be the only lawful route for the UK to voluntarily withdraw from the EU.

The formal withdrawal process will be initiated by a notification issued to the European Council stating the UK’s intention to withdraw from the EU pursuant to Article 50(2) TEU. The timing of the notification is the decision of the UK, and informal discussions on the withdrawal may take place before the notification is issued. Following the notification, the European Council will draw up negotiating guidelines without the UK’s participation. Negotiations will then take place between the EU negotiator and the UK over the terms of the withdrawal agreement.

Can the EU prevent the UK’s withdrawal?
There is debate over whether the UK could be prevented from leaving the EU in the absence of a withdrawal agreement. Under Article 50(2) TEU, the EU is under an obligation to negotiate a withdrawal agreement rather than the withdrawing Member State, the UK. However, a House of Commons briefing paper has given an interpretation of Article 50(3) TEU which states that “having no withdrawal agreement would not stop the UK from leaving the EU”^[1]. It seems that a Member State, or for example the European Parliament, could veto the withdrawal agreement, but not the withdrawal itself.

Can the UK exit the EU immediately?
There is also debate over whether the UK could exit the EU immediately upon giving notice. The two-year cut-off point under Article 50(3) TEU exists, among other things, to enable the parties to draw a line under exit negotiations. Article 50 TEU does not envisage a reduction in the two-year period in any circumstances, thus the only obvious way to alter this would be a Treaty change, which would be a significant process in its own right. In the recent High Court proceedings, it was common ground amongst the parties that a conditional notice under Article 50(2) TEU, for example that the notice is only effective if Parliament approves the terms of any withdrawal agreement, could not be given. It was interestingly, and perhaps more controversially, common ground that a notice under Article 50(2) TEU, once given, could not be withdrawn.

The EU Treaties and the laws flowing from them will cease to apply to the UK from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification given by the UK under Article 50(2), unless the European Council, in agreement with the UK, unanimously decides to extend this period.

In addition, the withdrawal agreement may need to be ratified by the European Parliament and all Member States depending on the precise areas that it covers. This is discussed further below.

Would a withdrawal agreement require ratification?
The extent to which the UK’s future relationship with the EU can be dictated by the mechanics of negotiating the withdrawal agreement is unclear from the terms of Article 50 TEU.

The Government has stated that any details of the UK’s future relationship with the EU are likely to be contained in a separate agreement that would have to be negotiated alongside the withdrawal agreement^[2]. Article 50 TEU does not clarify whether the negotiation of each agreement should occur consecutively or simultaneously.

The final withdrawal agreement will require approval from the European Parliament via a simple majority of its MEPs^[3], and Member States via an enhanced qualified majority^[4].

The content of the agreements will determine whether ratification is required by both the European Union (in the Council of Ministers and the European Parliament) and by the 27 Member States acting in accordance with their national procedures. Agreements that address policy areas within the preserve of Member States, such as free trade, will be classed as a ‘mixed agreements’ and subject to additional ratification locally by each Member State. An agreement that addresses only the practicalities of the UK’s withdrawal should not require ratification.

The process for ratification varies between Member States and in some cases requires the involvement of National Parliaments. If a Member State chooses to block a withdrawal agreement that requires ratification, the UK may leave the EU without an agreed arrangement in place unless an extension to the two-year time limit is granted. However, there is an argument that an agreement that requires ratification may be applied provisionally pending ratification by Member States in any event^[5].

The UK Parliament may also be required to ratify the withdrawal agreement and any agreements that are considered ‘mixed’^[6]. In the UK, ratification takes a minimum of 21 sitting days, and both the House of Commons and House of Lords have the power to delay ratification^[7].

Next steps
The ball is in the UK’s court, as it were. Only once the UK eventually gives its notice under Article 50 TEU, formal negotiations for the UK’s withdrawal from the EU can begin.

Notes 
[1] Brexit: how does the Article 50 process work? House of Commons Library Briefing Paper, 30 June 2016, Page 31.
http://researchbriefings.files.parliament.uk/documents/CBP-7551/CBP-7551.pdf 
[2] HM Government Policy Paper, The process for withdrawing from the European Union, Cm 9216, February 2016, Paragraphs 2.15 and 3.6. 
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/504216/
The_process_for_withdrawing_from_the_EU_print_ready.pdf 
[3] MEPs from the UK are likely to be able to participate in the vote as they will still be members of the European Parliament. 
[4] An enhanced qualified majority would require 20 out of the 27 remaining Member States representing 65 per cent of the population to vote in favour of the agreement in accordance with Article 238(3)(b) TFEU. 
[5] Professor Wyatt in evidence to the House of Lords Select Committee on the European Union inquiry on The Process of Leaving the European Union, 8 March 2016, Evidence Session Number 1, Question 12. 
http://data.parliament.uk/writtenevidence/committeeevidence.svc/evidencedocument/european-union-committee/the-process-of-leaving-the-eu/oral/30396.html 
[6] V Miller and A Lang, Brexit: how does the Article 50 process work?, House of Commons Library Briefing Paper, 30 June 2016, Page 30.
http://researchbriefings.files.parliament.uk/documents/CBP-7551/CBP-7551.pdf 
[7] Constitutional Reform and Governance Act 2010, Section 20.