thumb|At the time of the referendum in June 1975 the UK was just one of nine member states that made up the [[European Communities.]]
The 1975 United Kingdom European Communities membership referendum, also known variously as the Referendum on the European Community (Common Market), the Common Market referendum and EEC membership referendum, was a non-binding referendum that took place on 5 June 1975 in the United Kingdom (UK) under the provisions of the Referendum Act 1975 to ask the electorate whether the country should continue to remain a member of, or leave, the European Communities (EC) also known at the time as the Common Market — which it had joined as a member state two-and-a-half years earlier on 1 January 1973 under the Conservative government of Edward Heath. The Labour Party's manifesto for the October 1974 general election had promised that the people would decide through the ballot box whether to remain in the EC.
In a 1975 pamphlet, Prime Minister Harold Wilson said: "I ask you to use your vote. For it is your vote that will now decide. The Government will accept your verdict." The pamphlet also said: "Now the time has come for you to decide. The Government will accept your decision — whichever way it goes." The electorate expressed significant support for continued EC membership, with 67% in favour on a national turnout of 64%.
This was the first national referendum ever to be held throughout the United Kingdom but due to the ancient principle of parliamentary sovereignty the result could not be binding on either the Government or Parliament, and would remain the only UK-wide referendum until the 2011 referendum on the Alternative Vote system was held thirty-six years later. It was also the only national referendum to be held on the UK's relationship with Europe until the 2016 referendum on continued EU membership.
The February 1974 general election had yielded a Labour minority government, which went on to win a very small overall majority in the October 1974 general election. Labour pledged in its February 1974 manifesto to renegotiate the terms of British accession to the EC, and then to consult the public on whether Britain should remain in the EC on the new terms, if they were acceptable to the government. The Labour Party had historically feared the consequences of EC membership, such as the large differentials between the high price of food under the Common Agricultural Policy and the low prices prevalent in Commonwealth markets, as well as the loss of both economic sovereignty and the freedom of governments to engage in socialist industrial policies, and party leaders stated their opinion that the Conservatives had negotiated unfavourable terms for Britain. The EC heads of government agreed to a deal in Dublin on 11 March 1975; Wilson declared: "I believe that our renegotiation objectives have been substantially though not completely achieved", and said that the government would recommend a vote in favour of continued membership. On 9 April, the House of Commons voted by 396 to 170 to continue within the Common Market on the new terms. Along with these developments, the government drafted a Referendum Bill, to be moved in case of a successful renegotiation.
The referendum debate and campaign was an unusual time in British politics and was the third national vote to be held in seventeen months. During the campaign, the Labour Cabinet was split and its members campaigned on each side of the question, an unprecedented breach of Cabinet collective responsibility. Most votes in the House of Commons in preparation for the referendum were only carried after opposition support, and the Government faced several defeats on technical issues such as the handling and format of the referendum counts.
The referendum did temporarily achieve Harold Wilson's ambition to bring the divided Labour Party together on the European issue; however, eight years later, Labour's 1983 general election manifesto pledged withdrawal from the Communities. It also significantly strengthened the position of the pro-marketeer (later pro-Europe) politicians in the UK Parliament for the next thirty years; however, the issue of continued membership, despite the outcome of the referendum, was ultimately never resolved and remained contentious.
In the decades that followed, successive UK governments integrated further into the European project by ratifying subsequent European treaties (in particular Maastricht and Lisbon) through Parliament but without any further public approval. The UK Government did however decide against adopting the euro after the pound was forced to withdraw from the European Exchange Rate Mechanism in 1992, in what became known as Black Wednesday. Despite this, increasingly Eurosceptic politicians believed that the principle of parliamentary sovereignty was being eroded, and called for a second referendum on Britain's membership of what by now had become the European Union (EU), which resulted in a narrow majority in favour of the UK leaving the EU.
Background
When the European Coal and Steel Community was instituted in 1952, the United Kingdom decided not to become a member. The UK was still absent when the Treaty of Rome was signed in 1957, creating the European Economic Community (the "Common Market"). However, in the late 1950s the Conservative government of Harold Macmillan dramatically changed its attitude, and appointed Edward Heath to submit an application and to lead negotiations for Britain to enter the Common Market. The application was made at a meeting of the European Communities (EC) in January 1963, but the French president Charles de Gaulle rebuffed and vetoed Britain's request. Despite the veto, Britain restarted talks with the EC countries in 1967; and in April 1970, shortly before the 1970 general election campaign, Heath — who by this time was the Conservative Party leader — said that further European integration would not happen "except with the full-hearted consent of the Parliaments and peoples of the new member countries".
1970 Conservative manifesto commitment
The 1970 general election saw all the major political parties commit to either membership or to negotiate with the European Communities. The Conservative manifesto for the election on the issue was committed to negotiating membership but not at any price.
thumb|left|upright|[[Edward Heath led the UK into the European Communities in 1973.]]
The Conservatives won a total of 330 seats (out of a total of 630) on 46.6% of the national vote share, gaining 77 seats, which gave them an unexpected overall majority of about 30 seats. Edward Heath became Prime Minister, and personally led many of the negotiations which began following the election; he struck up a friendship with the new French president Georges Pompidou, who oversaw the lifting of the veto and thus paved the way for UK membership.
Negotiations and accession
Negotiations on joining the EC first began on 30 June 1970 which was also the same day that the Common Fisheries Policy was first adopted and in the following year a UK Government white paper was published under the title of "The United Kingdom and the European Communities" and Edward Heath called for a parliamentary motion on the white paper. In a ministerial broadcast to the nation on 8 July 1971, ahead of the debate in Parliament, he said:
The debate itself took place between 21 and 28 October 1971, with the House of Commons debating directly whether or not the United Kingdom should become a member of the EC. Conservative MPs were given a free vote, Labour MPs were given a three-line whip to vote against the motion, and Liberal MPs were whipped into voting in favour of the motion. Prime Minister Edward Heath commented in the chamber just before the vote:
The House of Commons voted 356–244 in favour of the motion, a substantial majority of 112. Throughout this period, the Labour Party was divided, both on the substantive issue of EC accession and on the question of whether accession ought to be approved by referendum. In 1971 pro-Market figures such as Roy Jenkins, the Deputy Leader of the Labour Party, said a Labour government would have agreed to the terms of accession secured by the Conservatives. the bill passed its second reading in the House of Commons by just eight votes. In October 1972 the bill completed the legislative process in both the Commons and the House of Lords and was given Royal Assent completing ratification of the Accession Treaty and became the European Communities Act 1972 which was one of the most significant constitutional statutes ever to be passed by the UK Parliament in time for the accession entry date. The United Kingdom joined the European Communities as a member state on 1 January 1973, along with Denmark and Ireland. The EC would later become the European Union.
1974 general elections & Labour manifesto commitments
thumb|left|upright|Labour Prime Minister [[Harold Wilson]]
thumb|left|upright|The support of the Conservative Party, under [[Margaret Thatcher, was essential to the passage of the Government's European business in the House of Commons.]]
The initial euphoria and initial expectations of British membership after joining was very short lived as events in the Middle East would cause impacts which would be particularly felt within Britain. The Yom Kippur War would lead to an Oil embargo by Arab counties which would lead to the "Three Day working week" being introduced and would eventually lead to Edward Heath to call a snap election which would ultimately end his time as Prime Minister.
At the February 1974 United Kingdom general election, the Labour Party manifesto promised renegotiation of the UK's terms of membership, to be followed by a consultative referendum on continued membership under the new terms if they were acceptable. Labour would become the largest party but were without an overall majority but managed to form a minority government.
Within one month of coming into office, the minority Labour Government started the negotiations promised in its February manifesto on the basis set out in that document.