Britain's Prime Minister David Cameron Image Credit: REUTERS

Those who have witnessed David Cameron negotiating often contrast his style with Margaret Thatcher’s. Instead of swinging the metaphorical man-bag, he looks for common ground and enumerates the issues that remain controversial, striving to expand the former and resolve or defer the latter.

Like Tony Blair finalising the Good Friday agreement, he grasps the value of constructive ambiguity. The language of diplomacy is necessarily elastic, so things may be presented in different ways to different audiences.

In politics, as in life, the alchemy of deals has as much to do with momentum, linguistic creativity, impatience and exhaustion as it does with content. In a negotiating process, there is a point where everyone has been marched to the top of the hill, and the idea of marching back down again with nothing achieved remains conceivable — but no more.

Since launching this strategy four years ago, Cameron has played the part of the man wrapped in the union flag determined to squeeze a better deal from Europe, ready, if all else fails, to countenance departure. But that act is wearing thin. This prime minister is a clubbable man who relishes his seat at top table and does not happily leave any inner sanctum. He is also a master of the arts of political theatre, and knows that he must soon — perhaps very soon — change persona, adopting the mask of the campaign leader rather than the Brussels wheeler-dealer.

Brexit is but one of the dragons that the EU oligarchy must slay. Alongside the growing recognition that the EU’s institutions, as presently constructed, are failing to match the extraordinary challenge of 21st-century population mobility, elections loom next year for Angela Merkel and Francois Hollande. None of Cameron’s counterparts want the horse-trading to last much longer.

So there is now a clear timetable for the UK referendum, and one that weighs heavily on all the key protagonists in the negotiations. For Cameron, all else is now subordinate to this enterprise. On Friday, he held a hastily scheduled meeting with Jean-Claude Juncker, the European commission president (whose appointment he so vigorously opposed in 2014 ).

On Sunday Donald Tusk, the president of the European council, was his dinner guest at No 10: a private curtain-raiser for the proposals that Tusk is expected to publish shortly. If they provide an acceptable framework, the deal will be signed off (in theory) at the EU summit on February 18 and 19 — or possibly at a separate gathering, dedicated to the prevention of Brexit. The referendum itself would then be held on June 23.

Whatever Cameron squeezes out of his EU counterparts will be dismissed by the various “out” campaigns. Juncker could agree to copy out Magna Carta in his own handwriting, declare that the only good thing to come out of Brussels since the Schuman Plan in 1951 is sprouts, and apologise individually for every allegedly banned straight banana — and Nigel Farage would still say that the PM was “selling out” the nation.

More psychologically intriguing is the likely response to a deal of the in camp, presently gathered under the umbrella of Britain Stronger in Europe. There has been much coverage of the strong personalities engaged in the fight to leave the EU. But consider the oddity of the position in which most of the in camp’s leading figures, such as Danny Alexander, Peter Mandelson, and Brendan Barber, now find themselves. Many of them are lifelong champions of the EU, embattled defenders of common sense (as they see it) against the foghorn of the Eurosceptic press and the Tory party’s entrenched hostility to the EU. And now they await the return of a Conservative prime minister from the negotiations he himself forced so that he may lead the campaign to win a referendum some of them privately believe is a terrible mistake and a colossal gamble.

Never forget that Cameron, like almost every Tory of his generation, is a Eurosceptic to his fingertips, a Conservative who instinctively believes the EU to be (as he said in 2014) “ too big, too bossy, too interfering ”. Yes, he charged his party to stop “banging on” about Europe. But that was about winning votes, and sharing the electorate’s priorities, rather than a thaw in the Tory approach to the EU.

Indeed, Cameron’s trajectory led in precisely the opposite direction. In the 2005 leadership contest, he won the support of many on the right by promising to pull Tory MEPs out of the European People’s party (EPP), the principal centre-right grouping in the European parliament. Four years later he kept his promise, withdrawing his MEPs from the EPP and forming a new anti-federalist bloc, the European Conservatives and Reformists. In December 2011, to the fury of his coalition deputy, Nick Clegg, he “vetoed” a deal to reform the euro. In the same year his government passed the European Union Act, mandating that a national referendum be held whenever the EU threatened to encroach significantly upon UK sovereignty. Yet it was never enough for his querulous backbenchers. They hated coalition, and Clegg.

And they were furious that Cameron’s “cast-iron guarantee” to hold a referendum on the Lisbon treaty had been rendered null and void when it entered EU law. He and George Osborne had also concluded that the eurozone crisis was an opportunity to be exploited: as the third-biggest net contributor to the EU, Britain was in a decent position to demand renegotiation of its membership terms as the price for its cooperation with the institutional measures taken to safeguard the single currency. If the matter was to be put to people, the question had to be “in or out?”. All else would be evasion, so many years after the 1975 referendum. That, at least, was the logic that underpinned Cameron’s Bloomberg speech in January 2013 promising a vote on Brexit before the end of 2017.

We do not yet know which politician will lead the out campaign. But — barring a historic upset — it will be Cameron who heads the opposing team. Like a quick-change artist, he will ditch the outfit of a hard-nosed Eurosceptic negotiator and present himself afresh as an enthusiast for the new EU and Britain’s place in it. He has to persuade the voters that they absolutely must remain part of a continental alliance about which he has been at best extremely critical and at worst downright dismissive.

There are those who see this as a potential advantage to the in camp, on the basis that the default position of the British people is essentially that of an instinctive Eurosceptic who is nonetheless unwilling to risk exit from the EU fold. But there is also scope for confusion, not to mention cognitive dissonance: why is this pro-EU campaign being led by a politician who patently dislikes what he is defending? Will the in camp be a broad church or a Babel? We’ll know soon enough. Prepare to step through the looking glass.

Why is this pro-EU campaign being led by a politician who patently dislikes what he is defending?

— Guardian News & Media Ltd

Matthew d’Ancona is a visiting research fellow at Queen Mary University of London and author of several books including In It Together: The Inside Story of the Coalition.