Title: In graphics: Britain's referendum (in Spanish, referendo or ) on EU membership.

On february 20th David Cameron, Britain's prime minister, set June 23rd as the date for a referendum on the country's membership of the European Union. His announcement followed a (prolongada, extensa) renegotiation of the current conditions of Britain's membership at a (cumbre) in Brussels.

The move immediately prompted government ministers to declare their backing for either the "remain" or "leave" campaigns. Mr Cameron strongly believes in the benefits of continued EU membership, but a handful of (notorios, prominentes, importantes) MPs, including (Lord Chancellor), Michael Gove, and London's mayor Boris Johnson, have (vowed) support for the "out" (in Spanish, activistas).

In early 2015 the chances of "Brexit" —Britain departing from the European Union— seemed remote. Today, largely because of Europe's migration crisis (in Spanish, o inmigratoria en Europa o ) and the interminable euro mess, the (encuestas) have narrowed.

Mr Cameron is himself partly responsible. Although he has repeatedly urged his party to stop " (talking insistently) about Europe", his Europsceptic (parlamentarios), (sin palabras) by the rise of Nigel Farage's virulently anti-EU UK Independence Party (UKIP), have constantly (insistido, molestado, incordiado) him to adopt a tougher line with Brussels. His response has generally been to (apaciguar) them. One early (concesión) he threw them was the 2011 European Union Act, which requires any EU-wide traty that passes substantive new powers to Brussels to be put to a British referendum

"Purple phase" (in Spanish, "").

Yet he was deliberately vague about what changes he wants, partly for fear that if his (the list of what he's going to do) (se filtra) Eurosceptics in his own part will rubbish it as inadequate.

He did produce a list of demands but a deal still eludes him (in Spanish, ).

The two campaigns, "Britain Stronger in Europe" and "Vote Leave", that are likely to form the official lobby groups (in Spanish, ) for each side in the referendum have set out their positions on the main topics that will form the basis for the referendum.

Britain's (complicada, tensa) relationship with the European Union has a long history.

Instead, in 1960 Britains cajoled six much smaller European countries into forming the (EFTA) (in Spanish, ()).

The effects of EU membership of trade patterns are difficult to measure, but John Springford of the Centre for European Reform, a London-based think-tank (in Spanish, ), and colleagues have carried out a modelling exercise which concluded that Britain's trade with the rest of the EU was 55% greater that it would have been if outside.

Regulation is perhaps the Eurosceptics' biggest (caballito de batalla, cuco).

Broadly, there are five models to choose from. The first is to join the European Economic Area (in Spanish, ).

The fourth is simply to rely on normal (WTO) (in Spanish, ) rules for access to the EU market.