The agreement between the EC (as it was at the time) and Turkey, according to which the EU-Turkey customs union works, is set out in a 1995 decision of the EC-Turkey Association Council. Its provisions are very unilateral, as is apparent from its final interpretative article: prior notification is required in all cases, except Norway and Switzerland. Norway and the EU, as well as Switzerland and the EU, constitute a kind of common security area with regard to import risk assessment. Both parties no longer require prior notification for goods from the other country. Goods from third countries are preclassified only in the first country and the results of the risk analysis are transmitted to the customs authorities of the other country if the goods continue to travel. These agreements are the result of bilateral agreements between these countries and the EU. Finally, Turkey is also a member of the Euro-Mediterranean Partnership and, as such, interested in concluding free trade agreements with all other Mediterranean partners in order to create a Euro-Mediterranean free trade area, initially envisaged until 2010. The obligation for member states not to conclude individual trade agreements with third countries has been enshrined in EU treaties since the original Treaty of Rome, which gave the European Commission „exclusive competence“ to negotiate external trade agreements. An overview of existing free trade agreements between the EU and third countries can be found on the EU website. It should be recognised that those restrictions on the rights of individual members of a customs union are inherent in the very nature of a customs union. They cannot be renegotiated, otherwise it will cease to be a functioning customs union.
However, some EU regions do not participate in the customs union: the Union Customs Code (EIP), which aims to modernise customs procedures, entered into force on 1 May 2016.  Implementation will take place over a specified period of time and full implementation is scheduled for 31 December 2020 at the latest.  The European Commission has stated that the objectives of the UZK are simplicity, service and speed. One of the ideas that emerged right after the Brexit referendum was to move the customs border inland, either by moving infrastructure inland or by changing when/where customs declarations are deposited. . . .