In this section
Our European Union membership is a divisive topic; it was when we entered in 1973, and has remained the case ever since the membership referendum two years later.
Ironically, according to the EU's own research in 2011, "the vast majority of Britons (82%) said that they knew either little (68%) or nothing (14%) about the EU's institutions and policies".
When the United Kingdom joined the European Economic Community (EEC) in 1973, the institution was primarily economic in nature, although aimed in principle at "ever closer union". Britain's accession, along with Ireland and Denmark, took the number of EEC member states to nine—all Western European.
Since 1973, the EEC has continued to expand in size. There are now 28 member countries, spanning Europe from Finland to Malta and from Ireland to Cyprus.
As the Community—subsequently Union—has grown, its political and economic powers have expanded too. This expansion came in the form of five major amendments to the original Treaty of Rome (1957)— with the last being the Treaty of Lisbon (2009). All of these were agreed by the government and ratified by Parliament.
All kinds of claims are made about our membership of the EU, from the number of laws that come from 'Brussels' to the jobs supported by trade with fellow members. But in today's debate, one issue stands out above all: immigration.
In 2013, 77% of British people said that they wanted to see a reduced number of immigrants. But EU Treaties, and the legislation fleshing them out, allow EU citizens to work and live in any member country.
With the EU's expansion in 2004, 10 new states joined the Union, including eight former members of the Eastern Bloc and Yugoslavia. The government's low estimates of how many migrants would come to the UK to find work were wide of the mark: EU immigration to the UK increased dramatically after 2004, and has almost reached non-EU levels of immigration in the latest figures (the figures are on page 32).
Focus on the manifestos and campaign statements of the Conservatives, Labour and Liberal Democrats, as we have in this report, and you'll find that much of this debate is muted. The relative scarcity of claims means that we don't have many EU claims to tackle—yet.
What is clear from the party manifestos is that a campaign on the single issue of EU membership—in or out—is likely to follow this election. The Liberal Democrats will advocate a Yes vote "when that referendum comes", and are committing to hold one when there is a Treaty change involving a "material transfer of sovereignty from the UK to the EU". Labour makes a similar pledge of a "referendum lock", while the Conservatives say they'll hold a vote by the end of 2017.
The occasional flawed sample aside, national polls on voting intentions in a hypothetical EU referendum rarely show that a majority of those asked want to leave the EU. Recent polls from YouGov, Populus and Opinium show (to varying degrees) that more people wish to stay than leave, but polls occasionally produce narrow 'Brexit' outcomes. If we do have a referendum in 2017, polls consistently suggest that there are enough undecided voters to make the outcome unpredictable at this stage.
We'll be on hand throughout, armed with the evidence.