The UK’s rocky relationship with the EU

The U.K. has spoken: It has decided to end its relationship with the European Union.

What the country decided in its June 23 referendum is crucial for the country and the EU — especially, as experts have suggested, a Brexit may encourage other EU members to hold their own referendums.

CNBC takes a look at the U.K.'s roller-coaster relationship with Europe.

—By CNBC's Alexandra Gibbs.

When the European Economic Community (EEC) was established in 1957 — there were only six members: France, Germany, Italy, Belgium, the Netherlands and Luxembourg.

The EEC was set up to create stronger economic ties, following the death and destruction seen during World War II; with Winston Churchill calling for a "kind of United States of Europe" in 1946.

The community's aim was to create a common market, where goods, services and people could move around with greater ease.

During 1961, the U.K., Ireland, and Denmark all applied to join the EEC. However, in January 1963, French president Charles de Gaulle expressed his country's concerns over the implications of a U.K. membership especially as it had close ties to the U.S. Within a matter of days, countries who'd submitted applications had their EEC negotiations suspended.

De Gaulle said he would veto Britain's entry again when it re-applied in 1967; however, the country's application gained momentum after de Gaulle resigned as President in 1969.

The European Economic Community welcomed three new members to it group: Ireland, Denmark and the United Kingdom; bringing its total up to nine.

Labour leader Harold Wilson followed up on his election pledge and renegotiated the U.K.'s terms of membership in the EEC, putting the outcome to a referendum. On June 5, 1975, the U.K. voted to remain in the EEC, with around 67 percent in favour of staying.

In 1984, Britain successfully negotiated a budget rebate with the EEC, after Prime Minister Margaret Thatcher threatened to halt payments. At the time, the U.K was set to become the budget's biggest net contributor—largely due to available access of farming subsidies—despite being one of the poorest members, according to the U.K. parliament's website.

In 2005, the country agreed to let go of some of its rebate, to help finance the EU's enlargement plans.

In 1979, the European Monetary System and its exchange rate mechanism (ERM) were introduced in the hope of achieving currency and exchange rate stability in Europe. Britain opted out of the ERM, but briefly joined in the early 1990s, only to unceremoniously leave it during the Black Wednesday currency crisis in 1992.

In 1992, the Maastricht Treaty was signed, highlighting how the bloc had grown from focusing solely on economic policy, to one that covered many topics. The treaty marked the name change and replacement of the EEC to the "European Union", while setting out rules for the EU's future currency: the euro.

The euro officially launched in 1999, and by 2002, 12 members had adopted the currency when coins and notes entered circulation. The U.K. opted out.

When the global financial crisis surfaced, many European countries who'd borrowed heavily for years were hit badly. The countries hurt most by the crisis received financial support from the IMF, European Central Bank and other EU countries.

In January 2013, Prime Minister David Cameron said if the Conservatives won the 2015 election, the government would work hard to renegotiate the country's membership with the EU, giving citizens a referendum to decide whether they wanted to remain in the bloc.

On May 27, 2015, Queen Elizabeth II set in motion the policies and proposed legislation set out by the new Conservative government, including the European Union Referendum Bill.

In mid-February, David Cameron managed to negotiate a reform deal with EU leaders on areas including competitiveness, financial protection, migration and the referendum, which had its date officially set that week as June 23, 2016.

From then on, the political rhetoric from both campaigns intensified and on April 15, Britain's official 10-week EU Referendum campaign kicked off.

After the polls closed and the votes were tallied, on June 24, 2016, the U.K. announced that it had voted to leave the European Union.

Results of the votes from the U.K. referendum on its EU membership showed 51 percent voted to leave the European Union. Prime Minister David Cameron, who pushed for the UK to remain part of Europe, announced his resignation.