Résumé:
Brexit, is the United Kingdom’s withdrawal from the European Union, which it has been inextrically for four decades. Eurosceptists motivated by strong sense of nationalism and soveignty, have long expressed reservations about UK’s participation in the EU and the impact of the latter on their way of life, citing security, defence, terrorism, immigration and nuclear power technologies. The UK has crucial role in EU, through its contribution to the EU budget. It gives significant financial support to EU security efforts, Defence and Security issue will be a major element of any EU-UK framework agreement. The Exit was not easy for both policies in which they have to prospect for the future security cooperation between EU and UK.