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David Cameron does not, according to his closest friends, “do dark nights of the soul”.
Which is just as well, since he has put his country’s future in the EU, the unity of his Conservative party and his own career on the line in a referendum that he admits will be “very close”.
“Nobody knows what is going to happen,” he says, sipping coffee from an “In” mug in his Downing Street study. But he insists he is not losing sleep ahead of Thursday’s vote. “I hope I look lively and alert,” he says. “I am working bloody hard.”
Mr Cameron, without tie and with a light tan, insists he has no regrets about calling the EU referendum back in 2013, although in reality his hand was forced by increasingly restive Tory MPs anxiously looking over their shoulder at Nigel Farage’s United Kingdom Independence party.
“In the end you have got to ask and answer this question,” he tells the Financial Times in an interview. “Europe has changed a lot since the 1970s. If not now, we would have to have this [vote] in the future.”
Nor does the prime minister regret not delaying the moment until later in his second term in Number 10. “I wanted to get on with it because there was always going to be a Brexit chill,” he says, referring to economic uncertainty over the result.
Mr Cameron insists he will stay on as prime minister if he loses on Thursday although many Tory MPs share the view of Ken Clarke, the former Tory chancellor, that “he wouldn’t last 30 seconds” if the country voted Leave.
He says the result is “in the lap of the people” but unsurprisingly wants to focus on what happens after a Remain vote, when he hopes to quickly reassert his authority both at Westminster and in Europe.
“As far as I am concerned this referendum should settle the matter,” he says, in a clear warning to Eurosceptic Tory MPs to accept the verdict of the people, not carry on fighting the same war.
“I believe it will one way or another be decisive. Britain will not want to go through this again. On the other hand if we vote to leave, this really is irreversible.”
In the event of a Remain vote he will try to bolster his position, shaken by months of Tory infighting on Europe, with a promise that he will be magnanimous in victory.
“Political parties are teams, broad churches,” he says. “You have to put your best players on the pitch, you have to bring parties together. It has been very hard and very tough. But referendums are always difficult.”
He has a “life chances strategy” — a series of policies to boost social mobility — ready to roll out and is planning a vote to renew the Trident nuclear deterrent that will unite the Tory party. His message to his MPs is: “Get on with it.”
Mr Cameron will also travel to Brussels next Tuesday for an EU summit to examine the referendum’s entrails. He claims a Remain vote will make him a “strengthened” figure in Europe, better able to promote a British agenda.
He says he would push for new trade deals and new co-operation in fighting terrorism — Britain holds the EU presidency next year — as well as for wider economic reform.
“We are the reformers,” he says. “Reform ends if we leave, not just for us but also our friends in Europe who want our voice heard in Europe.”
If Mr Cameron keeps Britain in the EU, he may still be greeted warily in Brussels; some fear other countries could demand their own special deals and hold their own referendums. If he loses, the atmosphere will be glacial.
The prime minister insists a Brexit vote would not lead to the unravelling of the EU. “I do not think if we were to leave we would suddenly see Denmark or the Netherlands doing the same thing,” he says.
But he adds: “I think us leaving would have an enormous and bad effect on the rest of the EU.” The EU would respond by deepening integration and becoming more of a “political project”. “It would not only be damaging ourselves but also the kind of Europe we want,” he says.
Should the prime minister not take some of the blame for the fact that British voters are so resolutely unconvinced about the merits of EU membership? Hasn’t his recent enthusiasm for the European project come a bit late in the day?
UK’s EU Referendum: How people would vote
For a more detailed summary of opinion polling visit the FT’s Brexit poll tracker page
There are some in Brussels who wish Mr Cameron had started countering the problem at an earlier stage. Martin Selmayr, chief of staff to European Commission president Jean-Claude Juncker, recently joked that Mr Cameron’s recent speeches made him “a contender for the Charlemagne Prize”. Hasn’t his Euro-enthusiasm come a bit late in the day?
“I do not accept that,” he says. “I would say that my position has been the same throughout my political life. I always said the best outcome was for Britain to remain part of a reformed European Union. There have been no deathbed conversions.”
But he is now willing to admit that his view of the EU has changed during his time as prime minister in one respect: he now sees that the idea that 28 countries working together — for example, imposing sanctions on Russia — is an important part of Britain’s security.
“Nato is the cornerstone of our security but the EU has a growing and important and worthwhile role in exchanging information on terrorism, criminals and borders,” he says.
With that the prime minister is off to conduct a final round of interviews and to make a last-ditch television appeal to the British people, framed by the door of 10 Downing Street, his home for the past six years but perhaps not for much longer.
Mr Cameron’s team admit to being nervous, but one ally insisted the prime minister would prevail. “His legacy will be that he pulled the economy back from the brink, kept Scotland in the Union and kept Britain in the EU. Just you wait and see.”
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