Europe is facing a social crisis like never before, and this comes just after an economical one. The huge flow of migrants that started crossing into Europe at the end of 2015 was just the straw that broke the camel for Great Britain, because the brits were threatening to leave the EU for some time. Prime Minister David Cameron has warned  his European counterparts that his country might leave if his demands are not met. He clearly affirmed that he wants to stay in the EU, but under different rules. He negociated a package of reforms, demanding concessions from a frightened Brussels, that has seen almost innevitable the change in some EU treaty terms. The PM used the 2011 European Union Act at the negociations, document which requires any EU treaty that passes new powers to Brussels to be put to an internal British referendum.  On June 23^rd these is set a referendum on the country’s membership to the EU. But this amount of incertainty led to the fall of the pound (reaching its lowest level since 2009), to fear for the investors and furious debates between the political parties. We shall further analyse the Lisbon Treaty, in order to better understand the legislation behind this european-wide tension, and to explain the implications of such an event.