The European Union

Britain joined the European Union have six advantage: Firstly, the possibility of increased specialization. To achieve economics od scale, that economy brings the EU companies in the international market to complete more effectively.
Secondly, in a larger market, greater competition to produce greater efficiency.
Thirdly, the EU countries to enjoy economies of scale and increased competition, it can produce faster growth.
Fourth, there are important political interests.
Fifth, the UK is the European Union, and a stable political background, it can attract investment, especially the US and Japan.
Sixth, it can the poorer of EU regions or the world's least developed countries to help.

While the disadvantages are direct contribution to the EU budget, the Common agricultural policy duo to rising food prices, the increased cost of manufacturing goods, services lack of competitiveness, and cumbersome procedures.

Overall, the UK joining the EU have advantages and disadvantages