Article 50 of the Treaty on European Union

Provisions

Article 49A of the Treaty of Lisbon, which came into force on 1 December 2009, introduced for the first time a procedure for a member state to withdraw voluntarily from the EU. This is specified in Article 50 of the Treaty on European Union, which states that:

1. Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements.
2. A Member State which decides to withdraw shall notify the European Council of its intention. In the light of the guidelines provided by the European Council, the Union shall negotiate and conclude an agreement with that State, setting out the arrangements for its withdrawal, taking account of the framework for its future relationship with the Union. That agreement shall be negotiated in accordance with Article 218(3) of the Treaty on the Functioning of the European Union. It shall be concluded on behalf of the Union by the Council, acting by a qualified majority, after obtaining the consent of the European Parliament.
3. The Treaties shall cease to apply to the State in question from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification referred to in paragraph 2, unless the European Council, in agreement with the Member State concerned, unanimously decides to extend this period.

Member state invocation

Article 50 of the Treaty on European Union provides that: "Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements." Once a member state has notified the European Council of its intent to leave the EU, a period begins during which a leaving agreement is negotiated setting out the arrangements for the withdrawal and outlining the country's future relationship with the Union. A withdrawal agreement would then be negotiated between the Union and that State.

Coverage in The Guardian explained that Article 50 could be invoked only by EU member countries although negotiations did not need to be entered into until invocation.

Remaining members of the EU consequently would need to undertake negotiations to manage change over the EU's budgets, voting allocations and policies brought about by the withdrawal of any member state.

Post invocation process

The treaties cease to apply to the member state concerned on the entry into force of the leaving agreement, or in the absence of such an agreement, two years after the member state notified the European Council of its intent to leave, although this period can be extended by unanimous agreement of the European Council. The two-year period of time in which the terms of the withdrawal agreement are negotiated is known as the sunset period.

The agreement is concluded on behalf of the Union by the Council and must set out the arrangements for withdrawal, including a framework for the State's future relationship with the Union. The agreement is to be approved by the Council, acting by qualified majority, after obtaining the consent of the European Parliament. For the agreement to pass the Council of the European Union it needs to be approved by at least 72 percent of the continuing member states representing at least 65 percent of their population.

This system gives a negotiated withdrawal, due to the complexities of leaving the EU (particularly concerning the euro). However it does include in it a strong implication of a unilateral right to withdraw. This is through the fact the state would decide "in accordance with its own constitutional requirements" and that the end of the treaties' application in said state is not dependent on any agreement being reached (it would occur after two years regardless).

The remaining members of the EU would also need to undertake negotiations on how to make the necessary changes to the EU's budgets, voting allocations and policies.

Should a former Member State seek to rejoin the European Union, it would be subject to the same conditions as any other applicant country.

This provision does not cover certain overseas territories which under TFEU Article 355 do not require a full treaty revision.

Pre-Lisbon situation

Before the Treaty of Lisbon entered into force on 1 December 2009 no provision in the treaties or law of the EU outlined the ability of a state to voluntarily withdraw from the EU. The European Constitution did propose such a provision and, after the failure to ratify it, that provision was then included as Article 50 of the Lisbon Treaty.

The absence of such a provision made withdrawal technically difficult but not impossible. Legally there were two interpretations of whether a state could leave. The first, that sovereign states have a right to withdraw from their international commitments; and the second, the treaties are for an unlimited period, with no provision for withdrawal and calling for an "ever closer union" – such commitment to unification is incompatible with a unilateral withdrawal. The Vienna Convention on the Law of Treaties states where a party wants to withdraw unilaterally from a treaty that is silent on secession, there are only two cases where withdrawal is allowed: where all parties recognise an informal right to do so and where the situation has changed so drastically, that the obligations of a signatory have been radically transformed.

There is no precedent for a sovereign member state leaving the European Union or any of its predecessor organisations. However, three territories of EU member states have withdrawn: Algeria (1962, independence from France), Greenland (1985) and Saint Barthélemy (2012), the latter two becoming Overseas Countries and Territories of the European Union.

Situation in the United Kingdom

After a referendum on the United Kingdom's membership of the European Union in June 2016 supported exiting the European Union, the Prime Minister Theresa May announced in October that Britain was going to invoke Article 50 by the end of March 2017. A quick invocation is widely seen as the preferred route for European institutions and member governments. On 26 January 2017, in a court case, the UK Supreme Court decided that an act of Parliament was required before this could be done.

Until Article 50 is invoked, the UK remains as a member of the EU continuing to fulfill all EU-related treaties and must legally be treated as a member and there is no official negotiation between the UK and the other states until Article 50 is invoked, although there have been unofficial contacts and negotiating positions have been publicly laid out by parties such as the European Council (of heads of national governments).