The idea of a united Europe dates back several centuries, but in the years following the Second World War, it seemed more necessary to the European countries.
The reasons for having a European supranational organization lay in political and economic motives. The political motive was based on the idea that only a supranational organization could eliminate the threat of war between European countries. And the economic motive rested on the belief that larger markets would promote competition and thus lead to greater productivity and higher standards of living. In short, the principal goal is to promote and expand cooperation among member states in economics and trade, social issues, foreign policy, security and defense, and judicial matters.
While the European countries viewed this Community as a favorable place for achieving more cooperative goals, not all European states did fully join it – the UK, which is neither a member of the Euro zone nor of the Schengen Agreement, is an outstanding example.
The British government initially refused to participate in the negotiations leading to the setting up of the European communities in the 1950s, then applied to join in the 1960s and was twice rebuffed. Entry was finally negotiated in 1971 and Britain became a member in 1973.
The story of how the UK's relationship with Europe has played a major role in British politics and that the relationship between Britain and the European Union has been, and remains, controversial shows the nature of British ambivalence towards the integration process which became apparent soon after it was introduced.
Chris Gifford believes the UK-EU relationship has always been a “matter of intense political debate since the Macmillan government first proposed British membership in 1961”. 
Researchers believe Britain was not willing to join the negotiations related “to the establishment of a Common Market of six leading western European powers” held in 1957. Britain was just interested in being “involved in free trade initiatives”. 
British uncertainty over staying in the EEC even led to a referendum being held in 1975. This referendum was important, because it was the first time the population “had been asked to decide a specific issue” and also because entering the EEC shifted the center of power from British laws to “Brussels and European law” which had priority over the former wherever they may have conflicted. 
Interestingly, issues such as sovereignty loss, European budget and how the UK and EU should cooperate are still problematic after about more than two decades since the second half of Thatcher's tenure which raised an enduring controversy over Britain's relationship with the European Union.
It is said that what made British parliamentary sovereignty more important than those of other European states is that, unlike other European states which went through some political upheavals or revolutions, Britain enjoyed a long political stability.
Public opinion about British national sovereignty should also be considered important and that, from the beginning, it was thought that if the Westminster parliament had conceded its power to the European Parliament, it would have been regarded as the loss of national power.
Euroscepticism believes that, as Stuart McAnulla mentions, treaties like “the Single European Act (1986) and the Maastricht Treaty (1993)” have meant to ‘Europeanize’ British politics. 
The question of whether Britain would give more power to Brussels rather than to its own national parliament is what different administrations dealt with in various eras and it is no different under Mr. Cameron. While Mrs. Thatcher made it clear in her Bruges speech given on Tuesday, 20 September 1988, that she was against how the European Community was being run and she opposed the idea of “European super-state exercising a new dominance from Brussels” , Mr. Cameron said in a statement to MPs: “over time” we will “take the opportunities for Britain to shape its relationship with Europe in ways that advance our national interest in free trade, open markets and co-operation….that should mean ... less Europe not more Europe. Less cost, less bureaucracy, less meddling in issues that belong to nation states.” 
As it is seen, the context for debates on the relationship between the UK and the EU has not changed much. A few days ago, almost 100 Tory backbenchers signed a letter to the Prime Minister asking him to give the British people a say on Europe after the next general election. They believe that Britain’s current relationship with the EU does not serve its interests. Mr. Cameron was told that the EU “meddles too much in our ordinary lives and has changed fundamentally from the institution the UK joined in 1973”. 
Clearly, the British have always tried to protect their interests and if the case was European Community’s budget in Mrs. Thatcher’s era and that she found out that about 70 percent of the budget was used for agricultural subsidies, while as Berlinski says “British agriculture sector was smaller and more efficient than those of its European counterparts,” and the economy of Britain did not depend on the agriculture, so Thatcher disagreed with the issue that the British people be asked to subsidize “European farmers to the tune of a billion pounds a year” , the case for Mr. Cameron is rather the same. While the European Commission is demanding a rise in spending that would mean an extra payment of £1.4 billion a year for Britain to the EU, Mr. Cameron told the summit that Britain’s budget rebate is “not up for renegotiation”. 
He also refers to Britain’s dissatisfaction with the European banking system and that Britain would not take part in any bail-out fund: “At Friday’s summit we ensured that the key parts of the banking union would be done by the European Central Bank for Euro zone members and not for us. We won’t stand behind Greek or Portuguese banks, and our banks will be regulated by the Bank of England, not the ECB.” 
Economics has always been of vital importance to Britain’s relationship with the EU and Charles Grant claims that “in addition to geography and history, economics helps to explain British euroscepticism”. 
Questions of whether to pursue European economic and political purposes have always played a role in Britain in dividing the country, splitting cabinets and toppling prime ministers, as in Mrs. Thatcher's case; though she won a majority of the vote in the following ballot in 1990, many cabinet colleagues left her due to her opinions on Europe and she had to resign.
Generally speaking, it can be considered understandable why Britain is not going to share power with the European Parliament – this means a loss of national sovereignty and less parliamentary power for Britain. The issue of national sovereignty has always been of a fundamental importance for the British government and public. As Mr. Cameron says, “for those of us outside the Euro zone, far from there being too little Europe, there is too much of it. Too much cost; too much bureaucracy; too much meddling in issues that belong to nation states or civic society or, indeed, individuals”. 
It is also interesting that while Mrs. Thatcher tried to have “my money back” for British interests, Mr. Cameron said he was looking for a “better balance of powers between Britain and Europe, because I would like to see some powers returned.” 
1. Gifford, Chris. The Making of Eurosceptic Britain: Identity and Economy in a Post-Imperial State. UK: Ashgate Publishing Limited, 2008. p:1
2. Evans, Eric. Thatcher and Thatcherism. 2th ed. UK: Routledge, 2005. pp: 78-79
3. McAnulla, Stuart. British Politics: A Critical Introduction. New York: Continuum International Publishing Group, 2006. p:166
4. ibid. pp: 40-41
5. Archer, Clive. Global Institutions: The European Union. UK: Routledge, 2008.p: 27
6. Prince, Rosa. “David Cameron: referendum on Europe may be necessary”. telegraph.co.uk. 02 Jul 2012.
7. Kirkup, James. “Cameron's backbenchers demand EU referendum”. telegraph.co.uk. 28 Jun 2012.
8. Berlinski, Claire. Why Margaret Thatcher Matters: "There Is No Alternative". New York: Basic Books, 2008. p: 316
10. Cameron, David. “David Cameron: We need to be clear about the best way of getting what is best for Britain”. telegraph.co.uk. 30 Jun 2012.
11. Grant, Charles. "Why Britain is eurosceptic?" Center for European Reform. 2008. (in pdf format) p: 2
12. Hennessy, Patrick. “EU: New Tory battle lines drawn”. telegraph.co.uk. 30 Jun 2012.
13. Prince, Rosa. “David Cameron: I'm not afraid to veto future EU integration to protect single market”. telegraph.co.uk. 03 Jul 2012.