Referendums that Have Shaped the EU

Britain will vote on whether to stay in the EU in a make-or-break referendum expected in June, after Prime Minister David Cameron sealed a reform deal in Brussels on Friday.

National referendums have often determined the direction taken by the European Union, whether by admitting new members, expanding its powers via treaty changes, or embarking on new projects:

- Enlargement -The then European Economic Community's first expansion was in 1973. Founding member France blocked British membership under President Charles De Gaulle, but in the end French voters agreed in April 1972 to admit Britain, Denmark, Ireland and Norway.

Danish and Irish voters then voted in referendums to join the bloc, while Norwegians voted to stay out. 

Britain did not hold a referendum on whether to join, but the Labour government of Harold Wilson organised one in 1975 on whether to stay in, to which Britons voted in favour.

In 1994 it was the turn of Austria, Finland and Sweden to vote to join what had become the European Union, bringing the bloc's membership to 15 on January 1, 1995. Norwegians voted for a second time to stay out.

Then, on May 1, 2004, 10 new countries, including eight members of the former communist bloc and two Mediterranean islands, joined the EU, taking its ranks to 25.

Nine of the incoming countries voted to join at referendums staged between March and September 2003: Czech Republic, Estonia, Hungary. Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia. Cyprus did not hold a referendum.

Croatia, which became the bloc's 28th member in July 2013, also voted to join in a January, 2012, plebiscite.

- Reforms and treaty changes -Under a series of reforms and new treaties, the EU has gradually expanded its powers and role.

Some EU member countries, such as Ireland and Denmark, are required under their constitutions to hold referendums to agree these changes, and the popular verdict has sometimes between negative.

- The Single European Act, which established a single market in the EEC from 1993, was agreed at referendums in both Denmark and Ireland.

- The Maastricht Treaty, establishing the European Union and laying the groundwork for European monetary union, did not go so smoothly.

On June 2, 1992, Danes sent shockwaves through Europe when they turned down the treaty.

They backed an amended version by a narrow margin in May 1993, but only after Denmark had secured greater autonomy in defence, currency, citizenship matters and judicial cooperation.

French voters, also consulted at a referendum, voted narrowly on September 20, 1992 to ratify the treaty. while Ireland also voted in favour.

- The Treaty of Amsterdam, which boosted the powers of the European Parliament, was approved by voters in Denmark and Ireland in May 1998.

- The Treaty of Nice contained key institutional reforms needed for the bloc's eastwards enlargement in 2004. It only faced a referendum in Ireland, where it was initially rejected in June 2001 after backers underestimated local opposition. After obtaining guarantees regarding Ireland's cherished neutrality, a second referendum was approved on October 19, 2002.

- The European Constitution: four countries held referendums. Spanish voters gave their approval in February 2005 and those in Luxembourg agreed in July of that year. Trouble broke out, however, when almost 55 percent of French voters said 'no' in late May 2005 and more than 61 percent of the Dutch rejected the document three days later. 

- Treaty of Lisbon: The treaty of reform to replace the doomed constitution. Once again, Irish voters initially said 'no' in June 2008 before changing their minds in October 2009.

- The European Budgetary Pact: This introduced the notion of the "golden rule," of balanced budgets was approved by an Irish referendum on the first try in mid-2012. Ireland was the only country to submit the pact to a referendum. 

- The euro -Two countries have held referendums on joining the euro since it was created in 1999, and in both cases Nordic voters rejected Europe's single currency.

In September 2000, just over 53 percent of Danes snubbed the euro, while in September 2003, neighbouring Sweden also held a referendum on the euro, which was rejected by 55.9 percent of those who voted.

- Switzerland -  Non EU-member Switzerland voted in 1992 against joining the European Economic Area agreement linking the EU and other Western European countries and in 2001 voted against applying to join the EU. It voted in favour of joining the EU's Schengen border-free zone in 2005.