In graphics: Britain's referendum on EU membership

Title: In graphics: Britain's referendum (in Spanish, referendo or [blank_start]consulta popular[blank_end]) 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 [blank_start]protracted[blank_end] (prolongada, extensa) renegotiation of the current conditions of Britain's membership at a [blank_start]summit[blank_end] (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 [blank_start]high-profile[blank_end] (notorios, prominentes, importantes) MPs, including [blank_start]justice secretary[blank_end] (Lord Chancellor), Michael Gove, and London's mayor Boris Johnson, have [blank_start]pledged[blank_end] (vowed) support for the "out" [blank_start]campaigners[blank_end] (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, [blank_start]crisis de refugiados[blank_end] o inmigratoria en Europa o [blank_start]el Mediterráneo[blank_end]) and the interminable euro mess, the [blank_start]polls[blank_end] (encuestas) have narrowed.

Mr Cameron is himself partly responsible. Although he has repeatedly urged his party to stop "[blank_start]banging on[blank_end] (talking insistently) about Europe", his Europsceptic [blank_start]backbenchers[blank_end] (parlamentarios), [blank_start]scared witless[blank_end] (sin palabras) by the rise of Nigel Farage's virulently anti-EU UK Independence Party (UKIP), have constantly [blank_start]hassled[blank_end] (insistido, molestado, incordiado) him to adopt a tougher line with Brussels. His response has generally been to [blank_start]appease[blank_end] (apaciguar) them. One early [blank_start]morsel[blank_end] (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, "[blank_start]fiebre púrpura[blank_end]").

Yet he was deliberately vague about what changes he wants, partly for fear that if his [blank_start]shopping list[blank_end] (the list of what he's going to do) [blank_start]leaks[blank_end] (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, [blank_start]se le escapa de las manos[blank_end]).

The two campaigns, "Britain Stronger in Europe" and "Vote Leave", that are likely to form the official lobby groups (in Spanish, [blank_start]grupos de presión[blank_end]) 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 [blank_start]uneasy[blank_end] (complicada, tensa) relationship with the European Union has a long history.

Instead, in 1960 Britains cajoled six much smaller European countries into forming the [blank_start]European Free-Trade Association[blank_end] (EFTA) (in Spanish, [blank_start]Asociación Europea de Libre Comercio[blank_end] ([blank_start]AELC[blank_end])).

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, [blank_start]laboratorio de ideas[blank_end]), 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 [blank_start]bugbear[blank_end] (caballito de batalla, cuco).

Broadly, there are five models to choose from. The first is to join the European Economic Area (in Spanish, [blank_start]Espacio Económico Europeo[blank_end]).

The fourth is simply to rely on normal [blank_start]World Trade Organisation[blank_end] (WTO) (in Spanish, [blank_start]Organización Mundial del Comercio[blank_end]) rules for access to the EU market.