An ‘opt-out’ is a technique used exceptionally where a majority of Member States wish to commit themselves to cooperate in a particular policy area within a Community framework, but one or more Member States refuse to join in the cooperation. To allow for progress in Community cooperation by those who wish to proceed, the reluctant Member States may ‘opt out’. The best-known example in the area of employment and industrial relations was when the United Kingdom obtained an ‘opt-out’ from the Agreement on Social Policy negotiated as part of the Maastricht Treaty in December 1991. There are other cases: the United Kingdom asked to be allowed not to take part in the third stage of Economic and Monetary Union (EMU), and similar clauses were agreed with Denmark as regards EMU, defence and European citizenship.
In an enlarged EU of 27 Member States, in the case of a requirement of unanimity, or even in the case of qualified majority voting, the function fulfilled by the ‘opt-out’ is likely to be more evident, as groups of Member States wishing to proceed to cooperate within the EU framework face resistance from a minority of Member States. A more sophisticated mechanism, providing a functional equivalent to the ‘opt-out’ is the ‘closer’ or ‘enhanced’ cooperation, envisaged by Articles 326 – 334 TFEU (originally introduced by the Treaty of Amsterdam). This allows the Council, acting by qualified majority on a Commission proposal, to authorise such closer cooperation within the Union framework, except for enhanced cooperation in the framework of the common foreign and security policy for which the authorisation is granted by a decision of the Council acting unanimously (Article 329 (1 and 2) TFEU.