“LET Europe arise!” Such was Winston Churchill’s exhortation at the conclusion of his 1946 speech in Zurich envisioning a “United States of Europe”. Britain would not be part of it; it had its own empire and Commonwealth. But Churchill said Britain, and others, “must be the friends and sponsors of the new Europe”.

There is something of this Churchillian loftiness in Britain’s call for the euro area to follow the logic of integration and save the single currency—as long as Britain is not involved. But whereas Churchill is sometimes claimed as a forefather of the European project, the interventions of David Cameron only seem to rankle.

In part, Mr Cameron comes across as annoyingly triumphalist even though Britain’s economy has worse debt and deficit figures than, for instance, France. Most exasperating is the prospect that Mr Cameron could seek to hold others hostage, blocking moves to integrate the euro zone unless, say, they agree to loosen Britain’s ties with the European Union.

All are aware of the Eurosceptics’ agitation for an in-out referendum on whether Britain should remain in the EU. Mr Cameron says he is not for leaving the union but does want to renegotiate the terms of membership, and then perhaps put the result to a popular vote. Amid the talk of repatriating powers, William Hague, the foreign secretary, this month launched an audit of the EU’s authority.

A separate reflection on the EU’s future, focusing on which powers to centralise in Brussels, is taking place among several foreign ministers convened by Germany’s Guido Westerwelle. Though Mr Hague is one of the EU’s “Big Three”, he is not invited. Moreover, Berlin is telling Britain bluntly that it “will not be blackmailed”. One worry is that Britain’s quest for renegotiation risks undoing decades’ worth of complex compromises that created today’s EU. A bigger concern is that it will hamper the euro area’s ability to respond decisively to its existential crisis.

The bust-up at last December’s European summit, when Mr Cameron vetoed the so-called “fiscal compact” to toughen budget rules, may have been a foretaste of rows to come. Though Britain would not have been bound by the pact, Mr Cameron demanded “treaty change for treaty change”. Specifically, he wanted a protocol to blunt the impact of EU financial regulation. In the end, Mr Cameron neither blocked the compact (25 of the 27 member-states signed a slightly messier version of it outside the EU treaties) nor got his safeguards for the City of London.

All sides have since tried to make up. British officials say their review of EU competences will serve as much to highlight the benefits of EU membership as to identify the powers to be repatriated. The review will make no recommendations and will not conclude until 2014, so its findings would probably only be acted upon after the next general election. For Nigel Farage, leader of the Eurosceptic UK Independence Party, it all smacks of “kicking the issue into the long grass”.

Events may redefine Britain’s relations with the rest of Europe rather sooner. A summit in June decided, with Mr Cameron’s assent, to create a single bank supervisor for the euro area, based on the European Central Bank (ECB), by the end of the year. Rescue funds could then be used directly to recapitalise ailing banks. This could be an important move towards greater risk-sharing. But there are many questions. How to distinguish between preserving financial stability (a matter for the 17 euro-area states) and preserving the single market in financial services (a question for all 27 EU members)?

Britain wants the ECB to take the supervisory role to ensure its remit extends only to the euro zone . Moreover, the legal instrument needed to create it gives Britain a veto. Yet the ECB only wants the job if it gets new powers, and access to funds, to restructure and wind down ailing banks, all backed by a credible system to guarantee bank deposits. Such matters fall under single-market rules that generally apply to 27 members, in which Britain has no veto.

Another conundrum is how to include those countries among the other nine non-euro “outs” that want to be involved. As the debacle over the fiscal compact shows, most “outs” would rather cleave to Germany than to Britain. Even if banking union can be enacted with existing powers, other forms of integration would require changes to the EU’s treaties. This includes “economic union” (to enforce common economic polices), “fiscal union” (with a path to joint Eurobonds) and “political union” (including boosting the European Parliament).

A big leap of integration?

A plan for all will be presented by senior EU figures in the coming months. Such changes could take years, but some of them could come sooner if the crisis takes a turn for the worse. The chronic problem of Greece will almost certainly return in the autumn. If euro-zone leaders refuse to give Greece more money, and push it out of the euro, a big leap of integration may be the only way of preventing a wider collapse.

Whenever the next treaty revision comes, Britain will still demand “treaty change for treaty change”. Yet another trigger for confrontation is the EU budget. Britain has support for its view that the seven-year budget for 2014-20 should be frozen in real terms. But it is a weak alliance, and many resent Britain’s long-standing budget rebate.

For now, everybody wants to avoid another blow-up with Britain. But an explosion can happen by mistake rather than by design. Britain is not the only country where anti-EU passions are stirring. Perhaps the euro will break up. Or perhaps it will consolidate. Both outcomes pose problems for Britain—and both will reshape its relations with the rest of Europe.

Economist.com/blogs/charlemagne