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.

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 referendum debate and campaign was an unusual time in British politics and was the third national vote to be held in seventeen months.

[5] 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.

The UK Government did 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.

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.

[7] If we can negotiate the right terms, we believe that it would be in the long-term interest of the British people for Britain to join the European Economic Community, and that it would make a major contribution to both the prosperity and the security of our country.

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 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"[8] and Edward Heath called for a parliamentary motion on the white paper.

Prime Minister Edward Heath commented in the chamber just before the vote:[citation needed] But tonight when this House endorses this Motion many millions of people right across the world will rejoice that we have taken our rightful place in a truly United Europe!The House of Commons voted 356–244 in favour of the motion, a substantial majority of 112.

In April 1972, the anti-EC Conservative MP Neil Marten tabled an amendment to the European Communities Bill, which called for a consultative referendum on entry.

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.

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.

[9] The government produced a white paper on the proposed referendum on 26 February 1975: it recommended core public funding for both the 'Yes' and 'No' sides, voting rights for members of the armed forces and members of the House of Lords, and finally a proposed single central count of the votes for the whole country.

However, another amendment, tabled in the Commons by Labour MP Roderick MacFarquhar, sought to have separate counts for each administrative region (the post-1974 county council areas): this won cross-party support, and was carried by 272 to 155 votes.

[11] The question that would be put to the British electorate, as set out in the Act was: The Government has announced the results of the renegotiation of the United Kingdom's terms of membership of the European Community.

Do you think that the United Kingdom should stay in the European Community (the Common Market)?A simple YES / NO answer was permitted (to be marked with a single 'X').

In spite of this, one minister, Eric Heffer, was obliged to resign after speaking against EC membership in the House of Commons.

The influential Conservative Edward du Cann said that "the Labour party is hopelessly and irrevocably split and muddled over this issue".

According to the treasurer of the 'Yes' campaign, Alistair McAlpine, "The banks and big industrial companies put in very large sums of money".

"[22] Tony Benn said there had been "Half a million jobs lost in Britain and a huge increase in food prices as a direct result of our entry into the Common Market",[21] using his position as Secretary of State for Industry as an authority.

[citation needed] The referendum was held nationally across all four countries of the United Kingdom as a single majority vote in 68 counting areas under the provisions of the Referendum Act, for which the then administrative counties of England and Wales and the then newly formed administrative regions of Scotland were used, with Northern Ireland as a single counting area.

On Friday 6 June 1975 at 18:30 BST the Prime Minister, Harold Wilson, gave his reaction outside 10 Downing Street as counting continued, although by this point the result was clear:[citation needed] 'The verdict has been given by a vote with a bigger majority than has been received by any Government in any general election.

It means that all those who have had reservations about Britain's commitment should now join wholeheartedly with our partners in Europe, and our friends everywhere to meet the challenge confronting the whole nation.'

Tony Benn said: "When the British people speak, everyone, including members of Parliament, should tremble before their decision and that's certainly the spirit with which I accept the result of the referendum.

The result strengthened Harold Wilson's tactical position, by securing a further post-election public expression of support for his policies.

In the House of Commons, the referendum result settled the issue of Europe for two years, until the debate about direct elections to the European Parliament began in 1977.

For the next forty-one years, the result provided a major pro-European direction to politicians, particularly in the UK Parliament and later in the newly devolved establishments in Northern Ireland, Scotland and Wales, until the 2016 EU membership referendum was held on Thursday 23 June 2016, when the UK voted by 51.9% to 48.1% to leave the European Union.

This was the only major UK poll in which Alastair Burnet was not involved in the TV coverage as lead presenter as he was editing the Daily Express at the time of the referendum and was taking a break from broadcasting.