The history of Great Britain and its integration into the European Union was always followed by huge interest and it regularly gave—and does even today—reason for the birth of a number of writings which contain either an historical or critical approach to the issue. My aim with the thesis is basically to provide a general historical description and also a story of evolution that started out from strong refusal and opposition to any idea of European integration, and ended in surrender as a result of serious changes in Britain’s attitude. For a start we must notice the fact that Britain has always been the one that colonised or occupied other countries and the other way round. This additional and quite unique piece of Britain’s history helps a lot in understanding the United Kingdom’s opposition to an organisation that is about merging countries into a unified whole and about the disintegration of borders. To a certain extent we may also consider integration as colonisation that takes away the independence of a country and from this aspect there is no wonder that Britain proved to be reluctant at the beginning. It must have a strange situation for Britain to get used to a kind of subordination where each country has to take responsibility and strive for equality. In case of Britain we cannot simply talk about physical isolation from the European continent but there are also significant factors in her history on the bases of which she has been considered an outsider for the participants of the integration. In the main parts of the thesis I would like to highlight the most relevant points in history that are inevitable to be considered for further analysis.