The withdrawal procedure from the EU is outlined in Article 50 of the Consolidated version of the Treaty on European Union:
- Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements.
- 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.
- 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.
- 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.
- If a State which has withdrawn from the Union asks to rejoin, its request shall be subject to the procedure referred to in Article 49.
The two referenced articles of the Treaty on the Functioning of the European Union are:
(ex Article 300 TEC)
3. The Commission, or the High Representative of the Union for Foreign Affairs and Security Policy where the agreement envisaged relates exclusively or principally to the common foreign and security policy, shall submit recommendations to the Council, which shall adopt a decision authorising the opening of negotiations and, depending on the subject of the agreement envisaged, nominating the Union negotiator or the head of the Union’s negotiating team.
(ex Article 205(1) and (2), TEC)
3. As from 1 November 2014 and subject to the provisions laid down in the Protocol on
transitional provisions, in cases where, under the Treaties, not all the members of the Council participate in voting, a qualified majority shall be defined as follows:
(a) A qualified majority shall be defined as at least 55 % of the members of the Council representing the participating Member States, comprising at least 65 % of the population of these States. A blocking minority must include at least the minimum number of Council members representing more than 35 % of the population of the participating Member States, plus one member, failing which the qualified majority shall be deemed attained;
(b) By way of derogation from point (a), where the Council does not act on a proposal from the Commission or from the High Representative of the Union for Foreign Affairs and Security Policy, the qualified majority shall be defined as at least 72 % of the members of the Council representing the participating Member States, comprising at least 65 % of the population of these States.