on 1 January 1973. United Kingdom's European Communities membership, 1975 — 1975 United Kingdom European Communities membership referendum, 5 June 1975, 67.2% in favour, turnout 64.0% The Conservative government of Edward Heath did not hold a referendum before the United Kingdom joined the European Communities in 1973. The Labour Party's manifesto for the 1974 general election included a pledge for an in-out referendum after a renegotiation of its membership. Accordingly, after Labour won under Harold Wilson, the referendum was held on whether to remain in the Communities after a renegotiation of its membership. The result was in favour of remaining. Greenland's European Communities membership, 1982 — 1982 Greenlandic European Communities membership referendum, 23 February 1982, 53.0% against In 1973, Greenland joined the European communities as part of Denmark. However, after the establishment of home-rule and eurosceptic Siumut winning the 1979 Greenlandic parliamentary election, a referendum on membership was agreed upon, in which the voters rejected remaining part of the communities. This resulted in Greenland negotiating the terms of its separation from the EU, resulting in the Greenland Treaty, and Greenland's leaving the communities in 1985. Single European Act Two referendums were held in EU countries to permit them to ratify the Single European Act. — 1986 Danish Single European Act referendum, 26 February 1986, 56.2% in favour, turnout 75.4% — a referendum to approve the Tenth Amendment of the Constitution of Ireland, 26 May 1987, 69.9% in favour, turnout 44.1% Maastricht Treaty — 1989 Italian advisory referendum, 18 May 1989, 88.1% in favour, turnout 81.0% Before the negotiations on the treaty of Maastricht began, Italy held a consultative referendum to give the European Parliament a popular mandate to elaborate a future European Constitution. After the treaty was signed, three countries held referendums on its ratification. — a referendum to approve the Eleventh Amendment of the Constitution of Ireland, 18 June 1992, 69.1% in favour, turnout 57.3% — 1992 French Maastricht Treaty referendum, 20 September 1992, 51.0% in favour, turnout 69.7% — The 1992 Danish Maastricht Treaty referendum, 2 June 1992, 50.7% against, turnout 83.1% In Denmark, two referendums were held before the treaty of Maastricht passed. The first one rejected the treaty. — The 1993 Danish Maastricht Treaty referendum, 18 May 1993, 56.7% in favour, turnout 86.5% After the defeat of the treaty in the first referendum, Denmark negotiated and received four opt-outs from portions of the treaty: Economic and