Regionalism is the creation of political, economic, or social structures loyal to a detailed analysis of a Geographic area with a similar population in terms of ideology and culture. Capitalism and state-to-state diplomacy are fundamentally based on regional integration. The ideas emphasize how interdependent and geographically significant states are. These nations are widely acknowledged as a single commercial bloc and are pursuing more ambitious political and economic goals. To accomplish this, member states' capitalism and intergovernmental systems come together. The European Union (EU) is Europe's attempt to become a regional organization, the most significant effort to establish regionalism in markets in the 20th century. The United Kingdom (UK) will leave the European Union on March 29 2019, leading to a new course in the world. When on June 23 2016, a majority voted in favour of the United Kingdom leaving the European Union (EU), it generated a host of unknowns. Over to the referendum, all are focused on anticipating the impact and implications of Britain's withdrawal from the European Union. This paper will add another piece to Brexit and its emergence. This paper tries to explain regionalism in Europe and European integration, the UK's Withdrawal referendum, and its Exit and also traces the importance of the political parties in Britain. Afterwards, it briefly introduces Britain's historically fractious relationship with the EU. In light of Britain's historical role, the remaining part of this paper goes on to estimate the background and impact of Brexit on the regional organization like European Union, which members and institutions within the organization emerges (the EU 27) will be best able to benefit from the strategic vacuum created the Brexit in the Globalized era.