Why is Britain in the European Union? It is a question asked by many Europeans. The continent increasingly wants to advance the construction of European and is constantly hampered by the reluctance of its British partner. The British Prime Minister, David Cameron, explained very clearly on Friday in Berlin: “Britain is in Europe because it is a nation dedicated to trade. This is the largest single market in the world. The single market is in part a British creation. We are proud of this creation.” In other words, Britain is not as interested in the political construction of Europe, it is only interested in the commercial advantages of being inside. And so the pound is not the euro. Not because the British thought that 20 years ago the euro would be a failure, as they say now, but for the opposite: they feared that it would have been so successful that it would eventually lead to greater political integration. And that loss of sovereignty is what they fear most. They want Westminster, in the end to always decide. And that is incompatible with a movement that is to make decisions. That is the element that shines behind the opposition of Margaret Thatcher to the single European currency. On October 20, 1990, The Economist published an editorial critical of Thatcher’s opposition which it stated is based “on prejudice and little else.” “Mrs. Thatcher objects because it would involve the European Monetary Union, she says that it is, ‘an unacceptable loss of sovereignty’. But this raises two questions: What kind of sovereignty and is it unacceptable for everyone, “the magazine wrote. The weekly downplayed the fact that London has lost its monetary sovereignty because of “an unmistakable lack of competence “, encouraging ups and downs of the economy. And, what is so shocking in the current debate is the criticism of opponents of the coin, “because they fear the loss of fiscal sovereignty, the power to take decisions on taxes and public spending.” “And to think that monetary union affects the fiscal sovereignty is a mistake, “he said. Thatcher’s successor, John Major, had no hostility to Europe and the single currency project. He who was in the Treasury, looked like a logical complement to internal market, but the divisions in his party caused him to distance himself from the project. First, he unsuccessfully proposed the creation of a common currency, but not only in parallel with national currencies. And then he tried to negotiate that Great Britain have the right to remain outside the European currency and choose when to enter. The famous opt-out. Labor would have suffered under Tony Blair if he had joined the euro if it was sure to win the referendum access, and if his rival Gordon Brown had took the euro as a hostage in their battles against him. Brown had doubts about the euro, but especially about the best time to enter, given the differences in the economic cycle and the British mainland. The critical techniques of monetary union have been particularly criticized by American academics, who stressed that Europe had no labor mobility, fiscal transfers, transfers, etc.