Many will have heard talk of the requirement for the Prime Minister to "trigger" Article 50 in the event of a vote to leave the European Union but there has been very little discussion about how Article 50 actually works.
What is Article 50
The Article 50 being referred to by the commentators is Article 50 of the Lisbon Treaty. The Lisbon Treaty became law in December 2009 and gave many of the institutions of the EU new powers whilst removing national vetoes in a number of areas.
Article 50 states that "Any Member State may decide to withdraw from the Union". The process set out in Article 50 requires the Member State to notify the European Council of its intention to leave the Union. Upon receiving this notice the EU must negotiate and conclude an agreement with the relevant Member State (Agreement) in the light of guidelines provided by the European Council.
As the European Council is made up of the heads of government of the Member States of the EU, the guidelines given by the Council will be highly political in nature and may themselves be contradictory and contested. As the departing Member State, the UK is not entitled to participate in the European Council meetings which determine the guidelines for the negotiation.
How will the process of leaving operate?
Once the European Council has determined the general guidelines for negotiations with the departing Member State, Article 218 (3) of the Treaty for the Functioning of the European Union (TFEU) requires the Commission to submit recommendations concerning the Agreement to the European Council who must adopt a decision to authorise the commencement of negotiations and appoint the head of the EU's negotiating team.
The Agreement must set out the arrangements for the Member States's withdrawal. It is a requirement that the Agreement takes "account of the framework for [the Member States's] future relationship with the Union" but there is no requirement for any details of the future relationship between the EU and the departing Member State to be provided for in the Agreement.
The EU and the departing Member State must conclude their negotiations within two years of the date upon which the European Council has received notification that the Member State intends to leave the EU. The EU Treaties will automatically cease to apply after the two year period has expired, unless the European Council unanimously agrees to increase this period.
How will the agreement be concluded?
Once the negotiations between the EU and the departing Member State have been concluded, the Agreement must be agreed by a qualified majority of the European Council. This requires the Agreement to be accepted by Council members representing a minimum of 55% of Member States and at least 65% of the EU population. The UK will not be permitted to participate in the European Council which determines whether to accept the Agreement and presumably the UK's population will be deducted from the population of the EU in determining the votes required in the European Council. In addition, the European Parliament must consent to the Agreement.
Despite the apparently clear structure for concluding the Agreement, the process of negotiations and approval will be inherently political. Every Member State will be considering the future of the EU following the vote by the people of the UK to leave the EU and different Member States will take different views on how aggressive the EU should be in its negotiating stance, particularly in relation to the UK's right to access the EU single market after it leaves the EU. The use of qualified majority voting means that a small number of Member States can block any provisions with which they disagree.
The process for negotiating the Agreement is likely to be complex and it remains to be seen whether an adequate Agreement can be put in place within two years of the process set out in Article 50 being triggered.