BREXIT: All you need to know about Britain's EU referendum

Britain holds a referendum on Thursday on whether it should remain in the European Union, following an often troubled relationship over recent decades.

What is the EU, why was it created and when was it formed?
British voters head to the polls on Thursday to decide if the country should stay in the European Union or leave it. With the stakes high and the issues complex, here are the ins and outs of the UK-EU relationship.

What is a referendum?
A referendum is basically a vote in which everyone (or nearly everyone) of voting age can take part, normally giving a "Yes" or "No" answer to a question. Whichever side gets more than half of all votes cast is considered to have won.
Why is a referendum being held?
Prime Minister David Cameron promised to hold one if he won the 2015 general election, in response to growing calls from his own Conservative MPs and the UK Independence Party (UKIP), who argued that Britain had not had a say since 1975, when it voted to stay in the EU in a referendum. The EU has changed a lot since then, gaining more control over our daily lives, they argued. Mr Cameron said: "It is time for the British people to have their say. It is time to settle this European question in British politics."
What is the European Union?
West Germany, France and four other nations formed the European Economic Community in 1957, determined to banish forever the bloodshed of two world wars. The grouping became the EU in 1993 and has grown into a 28-nation bloc of more than 500 million people stretching from Ireland to the Aegean Sea, with substantial powers over member states' laws, economies and social policies. It has its own parliament, central bank and 19 EU members use a common currency, the euro.

Why is Britain considering leaving?
Britain joined the bloc in 1973, but many Britons feel their island nation - a former imperial power with strong ties to the United States - is fundamentally different to its European neighbors. Anti-EU Britons resent everything from fishing quotas to fruit sizes being decided in Brussels.
The anti-EU view is especially strong in the Conservative Party of Prime Minister David Cameron. It was partly to appease his party that Cameron promised to hold a referendum on EU membership by the end of 2017. The prospect of Britain leaving the EU is known as "Brexit" - short for British exit.
Why do some Britons want to stay?
Supporters say Britain's economy and security are enhanced by EU membership. They argue that membership makes it much easier for British companies both large and small to import and export goods to other member countries with minimum hassle. Supporters say being part of the 28-nation bloc gives them many more options and makes it easy for them to live and work in other countries.

Labour Party leaders also argue that European rules and regulations and European courts have improved the way British workers are treated. They say removing these protections could lower living standards.
What issues are shaping the campaign?
The "remain" side, headed by the prime minister, argues that Britain's economy would suffer a tremendous blow if the country leaves the trading bloc. This position has been backed by many prominent business leaders who warn of a possible catastrophe.
The "leave" side has focused on concerns about immigration from other parts of the EU since membership in the bloc gives residents of other countries the right to live and work in Britain. They argue that by leaving, Britain can take total control of its borders and set up its own entry rules.
EU leaders have refused to compromise on the EU principle that citizens may live and work freely in other member states. But they have offered Britain an "emergency brake" that will allow it to restrict social welfare benefit payments for a period if it can show its welfare system is under pressure.
What happens next?
The referendum's outcome is hard to predict, because there is little precedent - Britain hasn't had a referendum on Europe since 1975. Opinion polls were notoriously inaccurate about Britain's 2015 election, and vary widely. Some show a lead for the "remain" side, while others put "leave" ahead.
 

Ahead of the vote, here are some key dates in Britain's relationship with the EU:
August 9, 1961: Britain makes its first formal application to join what was then the European Economic Community (EEC) under Conservative prime minister Harold Macmillan.
January 14, 1963: France's then-president Charles de Gaulle vetoes the application for the first time. He says 'Non' again on November 27, 1967 after Britain reapplied.
January 1, 1973: Britain finally enters the EEC at the same time as Ireland and Denmark, after De Gaulle has left office.
June 5, 1975: In a referendum on membership of the EEC, Britain votes "Yes" by slightly more than 67 percent.
November 30, 1979: Prime minister Margaret Thatcher demands a rebate on Britain's contribution to the European budget in a speech which became best known for a phrase attributed to her as: "I want my money back!"
September 20, 1988: Thatcher gives a landmark speech in the Belgian city of Bruges which became a rallying cry among eurosceptics for less European political integration.
November 22, 1990: Thatcher is forced to resign. Her growing euroscepticism was seen as a contributing factor as many felt it was lowering Britain's influence in Europe.
February 7, 1992: The Treaty of Maastricht, which underpinned the next stage of European integration, is signed. Britain secures an opt-out from joining the single European currency.
July 23, 1993: Prime minister John Major holds a confidence motion in his government over the Maastricht Treaty after serious infighting in his Conservative Party over Europe. He is caught on camera calling eurosceptic ministers plotting against him "bastards".
April 20, 2004: Labour prime minister Tony Blair, a europhile, announces his intention to hold a referendum on the European constitution. It is never held, after France and Denmark rejected it.
January 23, 2013: Conservative Prime Minister David Cameron promises a referendum on EU membership if his party wins the next general election.
May 22, 2014: The anti-EU UK Independence Party tops the polls in European Parliament elections with more than 26 percent of the vote, securing 24 seats.
May 7, 2015: Cameron's Conservatives win a surprise outright majority in the general election, clearing the way for a referendum to be held.
 
February 20, 2016: Cameron announces a date for the referendum after negotiating key reforms at a summit in Brussels.
April 15, 2016: Referendum campaign begins.