It follows that a country withdrawing from the UNION must also withdraw separately from a mixed agreement in order to no longer be part of the contracting parties. `Agreement` means the Agreement on the European Economic Area signed in Porto on 2 May 1992 and the Protocol of Adjustment signed in Brussels on 17 March 1993; The European Economic Area (EEA) was established by the Agreement on the European Economic Area (hereinafter referred to as the EEA Agreement), signed in Porto (Portugal) on 2 May 1992 and entered into force on 1 January 1994. The EEA was originally intended to establish an economic association between two economic blocs in Europe: the European Economic Community (now better known as the European Union or the EU) and the European Free Trade Association (EFTA). In this case, one of the EFTA members, the Swiss Confederation, opposed the ratification of the EEA Agreement. Consequently, the EEA Agreement between the EU and its Member States and the other EFTA States (Republic of Iceland, Principality of Liechtenstein and Kingdom of Norway) entered into force. The EEA therefore includes all current EU Member States (numbering as of the date of letter 27), as well as Iceland, Liechtenstein and Norway. EFTA still exists. The EFTA States, which are also members of the EEA, are often referred to as the EEA-EFTA States, but the term “EFTA States” is used in the EEA Agreement itself and in similar texts. For the avoidance of confusion, this Chapter uses the term `EEA-EFTA States` to describe the EFTA States which have signed the EEA Agreement. As did the EFTA Court of Justice in E-9/97 Sveinbjörnsdóttir  EFTA Ct. Rep. 95, para.
59, `the EEA Agreement is an agreement of international law sui generis which contains its own legal order`. There are therefore two legal systems that form the basis of the EEA Agreement: EU and EEA law. Within the EU, the provisions of the EEA Agreement may have direct effect (see, inter alia, Case T-115/94 Opel Austria v Council  ECR II-00039, paragraph 102). The EEA Agreement was transposed into the national law of the United Kingdom by the European Economic Area Act 1993. Accession to the EEA/EFTA is a feasible possibility in the draft political declaration between the UK and the EU. As Michel Barnier, the EU`s chief negotiator, on 29 November 2017 said: “Only the combination of the internal market and the customs union allows for smooth trade between us”. As this author has already mentioned, the “deep and special” partnership agreement with the EU desired by the Prime Minister could perhaps be best achieved on the basis of an updated version of the EEA Agreement. The Common Market 2.0 proposal, published in January 2019 by Lucy Powell MP and Robert Halfon MP on behalf of the Norway Plus multi-stakeholder group, depends entirely on the UK becoming an EEA/EFTA state. In the House of Lords, Lord Lea called for the UK to remain a member of a “family of developing EEA nations”. Given the proximity and content of these relations, which would certainly require a withdrawal agreement (in accordance with Article 50(1) of the EC Treaty). 2 TEU), the content and organisation of such a withdrawal agreement would be very different from the withdrawal agreement concluded between the United Kingdom and the EU, and not only as regards the content of the political declaration.
. . .