economic-political union of 28 member states. Initially it came about as a way to bring

together a collection of nations that had, on and off for centuries, been at war.

Germany and France entered a series of negotiations following the Second World War to ensure that

the two countries would never again be at odds. In 1952 a European coal and steel Community

agreement was signed between Germany and France and also included Belgium, Italy, Luxumbourg

and the Netherlands. In 1957 this was turned into the EEC or European

Economic Community through the Treaty of Rome. This founding group brought about the common

market. The first wave of EU expansion was in 1973

when Britain, Ireland and Denmark signed up. Since then Greece entered the group in 1981.

Spain and Portugal joined in ’86. Eastern Germany was absorbed in the year of German

unification in 1989 and then Austria, Sweden and Finland signed up in 1995.

The biggest single enlargement came in 2004 with Estonia, Latvia, Lithuania, Poland, Czech

Republic, Slovakia, Hungary, Slovenia, Malta and Cyprus, all signing into the EU.

Romania and Bulgaria signed up in 2007 and the most recent enlargement came in 2013 when

Croatia became a member. The EU, as we know it today, was formally

established in 1992 with the Maastricht Treaty. This document paved the way for the creation

of a single currency and the euro formally replaced banknotes of 12 member states in 2002.

In 2009 the current structure of the EU was

formulated through the Lisbon Treaty which reformed many aspects of the union and created

a permanent president of the European Council. While no EU member has ever left the union,

Greenland, which gained membership through its association with Denmark, withdrew because

of a dispute over fishing rights. Withdrawal from the European Union is a right

of EU member states under the Treaty on European Union (Article 50) which says "Any Member

State may decide to withdraw from the Union in accordance with its own constitutional requirements."

This is not the first time that the UK has

held a referendum on its membership of what is now the EU. In 1975 Britain voted by a

margin of two-to-one to stay in the European Economic Community, as the European Union

was then known. But will things change on the 23rd June?