Article 50 of the Lisbon Treaty
The right of a Member State to withdraw from the European Union was introduced for the first time with the Lisbon Treaty; the possibility of withdrawal was highly controversial before that. Article 50 TEU does not set down any substantive conditions for a Member State to be able to exercise its right to withdraw, rather it includes only procedural requirements. It provides for the negotiation of a withdrawal agreement between the EU and the withdrawing state, defining in particular the latter’s future relationship with the Union. If no agreement is concluded within two years, that state’s membership ends automatically, unless the European Council and the Member State concerned decide jointly to extend this period.
The legal consequence of a withdrawal from the EU is the end of the application of the EU Treaties (and the Protocols thereto) in the state concerned from that point on. EU law ceases to apply in the withdrawing state, although any national acts adopted in implementation or transposition of EU law would remain valid until the national authorities decide to amend or repeal them. A withdrawal agreement would need to address the phasing-out of EU financial programmes and other EU norms.
Experts agree that in order to replace EU law, specifically in any field of exclusive EU competence, the withdrawing state would need to enact substantial new legislation and that, in any case, complete isolation of the withdrawing state from the effects of the EU acquis would be impossible if there is to be a future relationship between former Member State and the EU. Furthermore, a withdrawal agreement could contain provisions on the transitional application of EU rules, in particular with regard to rights deriving from EU citizenship and to other rights deriving from EU law, which would otherwise extinguish with the withdrawal.
Article 50 – Treaty on European Union (TEU)
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.
4. For the purposes of paragraphs 2 and 3, the member of the European Council or of the Council representing the withdrawing Member State shall not participate in the discussions of the European Council or Council or in decisions concerning it. A qualified majority shall be defined in accordance with Article 238(3)(b) of the Treaty on the Functioning of the European Union.
5. If a State which has withdrawn from the Union asks to rejoin, its request shall be subject to the procedure referred to in Article 49.
To read more on Article 50 see: Article 50 TEU: Withdrawal of a Member State from the EU (PDF)