On eve of defining British EU referendum, rivals race for final votes

By Guy Faulconbridge and Michael Holden

LONDON (Reuters) - British Prime Minister David Cameron and his euroskeptic opponents made final pitches for wavering voters on Wednesday on the eve of a defining referendum on European Union membership with the outcome still too close to call.

The vote, which echoes the rise of populism elsewhere in Europe and the United States, will shape the future of Europe. A victory for "out" could unleash turmoil on financial markets.

"It's very close; nobody knows what's going to happen," Cameron told Wednesday's Financial Times, with opinion polls showing the rival camps neck and neck.

European Commission chief Jean-Claude Juncker warned there would be no further renegotiation whatever the result on Thursday, after EU leaders reached a deal on a new settlement for Britain in February. French President Francois Hollande said a vote to leave would carry a "very serious" risk of ending British access to the EU's prized single market.

The referendum will take place a week after the murder of ardently pro-EU lawmaker Jo Cox shocked the country, raising questions about the tone of an increasingly bitter campaign.

Much of the heated debate has boiled down to two issues: the economy and immigration.

The City of London financial center, the International Monetary Fund and the majority of British business leaders back Cameron and his Remain camp's stance that to leave the EU would plunge Britain into recession, costing jobs and raising prices.

Supporters of a so-called Brexit have struck a chord with many voters by saying Britain would regain control of immigration if it cut itself loose from a bloc they see as domineering and out of touch.

In what has become an ugly and personal fight, both camps have been accused of using unfounded assertions and scare tactics. Remain campaigners accuse their opponents of resorting to the politics of hate; the Leave camp say their rivals have run a "project fear" to scare voters about the economic risks.

Both sides hit the road and the airwaves to appeal to the large number of undecided voters who will be decisive, along with the level of turnout.

"INDEPENDENCE DAY"

"It's our last chance to sort this out and take back control," said former London mayor Boris Johnson, the main leader of the Leave campaign and favorite with bookmakers to replace Cameron in the event of Brexit.

"If we don't vote to leave tomorrow we will remain locked in the back of the car, driven in an uncertain direction frankly to a place we don't want to go and perhaps by a driver who doesn't speak the very best of English," he said.

He was flying around Britain in a helicopter to spread the Brexit message, making an unashamed play to British patriotism by declaring Thursday could be Britain's "independence day".

The leader of the anti-EU UK Independence Party (UKIP), Nigel Farage, also played the nationalist card in an address to supporters in London.

"They (the EU) have an anthem, they are building an army, they have already got their own police force, and of course they have got a flag," Farage said.

"At the end of the day tomorrow when people vote they must make a decision - which flag is theirs? and I want us to live under British passports and under the British flag."

Cameron, who called the referendum under pressure from his own Conservative party and from the insurgent UKIP, urged voters to remain in the club Britain joined in 1973.

"If we leave, we will diminish our country and our ability to get things done in the world," he told a crowd in Bristol in western England. "We've got one day left to hammer out that message; stronger, safer, better off (in Europe)."

Standing alongside him, former Prime Minister John Major said the result would have to be respected but added: "If they vote to leave on the basis of half-truths, untruths and misunderstandings then ... the gravediggers of our prosperity will have to account for what they have said and done."

Opinion polls have depicted a deeply divided nation, with big differences between older and younger voters, and between pro-EU London and Scotland and euroskeptic Middle England. Some polls published since Cox's murder have suggested a swing towards Remain, though often within the margin of error.