In the context of the pan-European accumulation, it may be necessary to determine the original character of goods which are in free practice in the customs union but which are exported or used in the production of products for export to other countries under the pan-European cumulative system. To this end, Decision 1/1999 of the CE-Turkey Customs Cooperation Committee of 28 May 1999 (OJ L 199 of 20.12.1999) 204, 04.08.1999, p. 43), a “supplier statement” submitted to the exporter and used by the exporter as evidence of origin under preferential agreements with other countries under the pan-European coordination system. By decision 1/2001 of the CE-Turkey Customs Cooperation Committee of 28.03.2001 (JO L 200 of 20.12.2001, p. 1). The provisions for the application of Decision 1/95 are agreed for the exchange of goods between the two parties of the customs union and with third countries (modified by Decision 1/2003 of 30.01.2003, JO L 155 of 16.12.2001, p. 1). JO L 28, 4.02.2003 – Corrigendum JO L 28, from 4.02.2003 JO L 74, 20.03.2003). Critics of a post-Brexit customs union have expressed the same concern and warned that a customs union could undermine Britain`s hopes of concluding individual trade deals and securing lucrative concessions in sectors such as services. Thirdly, the EU should send a clear message to Turkey that it is ready to deepen the existing trade agreement only if certain conditions are met.
Turkey should tackle and repair the growing number of trade irritations in recent years under the current agreement. This situation has been reported without exception by all the countries that participated in the joint research. Ankara should also honour its commitments to cooperate with Europe on migration management. Thirdly, Turkey should once again establish itself as a reliable partner for European security. This is only possible if the interest in multilateralism and diplomacy is sincere. Ankara should put an end to military threats in the eastern Mediterranean and act in the common interest of the transatlantic alliance. The customs union has increased both imports and exports to Turkey and its GDP per capita.  Turkey`s accession to the customs union has played an important role in the transition of its economy from agriculture to industry.
 The EU countries studied, such as Spain, Poland, Italy, Greece, France and Germany, have strong economic interests in deepening the somewhat obsolete 1995 trade agreement. Whether it is the economy or the ministries of trade, the major economic players in each of these six countries are aware of the significant potential for the trade benefits that an enlarged UC could offer. The panoply includes joint ventures in the fields of defence, renewable energy, the financial system and construction. A new agreement could facilitate access to public tenders and the country`s huge internal market. It could exploit Turkey`s potential as a tourist country and allow cabotage. Turkey is still seen as a promising hub for Central Asian and Middle East markets. A deeper size would ensure existing value chains and underline Turkey`s credibility as an investment objective. The EU and Turkey are bound by a customs union agreement that came into force on 31 December 1995.
The “final phase” under the Ankara agreement was to complete the creation of a customs union between the EC and Turkey. On 6 March 1995, the Association Council adopted a “decision on the customs union (Decision 1/95) ” on the implementation of the final phase of the customs union between Turkey and the EC. Thus, 22 years of “transition” were completed in the Additional Protocol on 1 January 1996 and the final phase of Turkey`s accession to the EU was launched.