LONDON • A potent force in British politics for decades, euroscepticism forced Prime Minister David Cameron to call a referendum on leaving the EU - and could still thwart his efforts to stay in.
Should Mr Cameron secure a deal at a Brussels summit yesterday and today to reform Britain's relationship with the European Union, the "remain" and "leave" camps will immediately begin the battle to win voters over for a referendum likely to be held in June.
Despite Mr Cameron's own support for staying in, some of his senior ministers, including Work and Pensions Secretary Iain Duncan Smith, look poised to come out in favour of the out campaign.
Many Britons, encouraged by an often hostile popular press, share their anti-EU views.
"I'm English and not European," said 80-year-old Fred Varley in the seaside town of Clacton-on-Sea, a hotbed of euroscepticism.
"I believe Germany has tried in two world wars to overtake this country and they've failed and they're doing it legally now through the European thing."
Some 51 per cent of Britons want to remain in the EU compared to 49 per cent who want to leave, according to an average of opinion polls by the What UK Thinks research project - though this average does not count the many voters who are still undecided.
"The most difficult thing about the referendum is that the arguments in favour are complicated, economic, numerical and rational," said Mr Charles Grant, director of the Centre for European Reform think-tank. "The arguments against are simple, emotional and romantic: do you want to be ruled by foreigners or not?"
Mr Cameron first promised an in-out referendum on EU membership in 2013 in a bid to placate powerful eurosceptics in his centre- right Conservative Party who harboured suspicions about the European project and were increasingly concerned by the rise of the anti- EU UK Independence Party.
The word euroscepticism seems first to have been used by The Times newspaper in 1986, but its roots go back further.
Britain had its bids to become part of the European single market vetoed twice by France in the 1960s, finally joining in 1973, and has since negotiated significant opt-outs. It does not use the euro, is not a member of the Schengen passport-free movement area and receives a significant rebate from yearly budget contributions.
"From Britain's perspective, it has never been totally committed to European integration as an end in itself because it always felt it has other options," such as ties with the US, said Mr Tim Oliver of the London School of Economics.
Eurosceptics face their own hurdles. With experts believing up to 20 per cent of voters are undecided, they must make a convincing case for a jump into the unknown by leaving the EU.
"The aim of the out campaign is to portray Europe as a burning building with an exit," Mr George Eaton, political editor of the New Statesman, wrote this month. "But like a cartoon character who succumbs to gravity in mid-air, voters fear a painful landing."