In what ways and for what reasons did Britain's attitude to Europe change during the period 1945 to 1991?

Winston Churchill who was the strongest supporter of unified Europe when again became prime minister in 1951 ironically was less enthusiastic towards this cause. Later in 1957 Conservative government decided not to sigh Treaty of Rome. There were several reasons for Britain’s refusal. One of the main objection was that if they join European community they would lose their economic sovereignty to European Commission in Brussels. There were also apprehensions that British membership will damage their relationship with commonwealth and ‘special relationship’ with the USA. At the same, time Britain was also worried that their goods will become uncompetitive in EEC market due to unfavorable import duties. To offset this Britain organized a rival group, the European Free Trade Association (EFTA).
However, within four years of deciding not to join Treaty of Rome, Britain changed its mind and expressed their wish to join EEC. In 1980 when people were talking about the concept of United States of Europe the then Prime Minister Mrs. Thatcher upset them by speaking against any movement towards political unification of Europe. Later in 1991, Britain objected to the ideas of federal Europe, a common currency and a whole section known as ‘the social chapter’ of Maastricht Treaty.
Reasons for the change of attitude towards Europe are:

• By 1961, EEC was a success. Compared to Britain 30% rise in production, French production rose at 70% and German at 90%.
• The commonwealth though had the huge population but their purchasing power was no way near to EEC.
• By joining EEC, it was expected that it will increase efficiency in British industries.