Complex negotiations to follow any UK referendum on EU membership

If David Cameron returns as prime minister after the UK general election next month, he will embark on a politically torturous, legally complex and diplomatically fraught effort to negotiate a new settlement for Britain in Europe - ideally enshrined in a new EU treaty.

Almost all EU leaders want to avoid serious treaty change, a big rewrite of the club's primary rule book. It carries huge political risks and can trigger unwanted national plebiscites.

Mr Cameron's dilemma is that eurosceptic Tory MPs see the ultimate proof of a new UK-EU relationship as being a new, revised treaty. This legal document has almost hallowed status for some.

Yet for fully-fledged treaty change, the two-year deadline before a 2017 referendum would involve EU institutions moving at light-speed. The current Lisbon treaty emerged from a bumpy decade-long process. Downing Street knows a more creative legal option may be required.

What does David Cameron want?

The Tory manifesto sets out a shopping list of reforms including protecting Britain's position in the single market against a powerful eurozone bloc, a return of powers from Brussels, a role for national parliaments to block unwanted EU legislation and excluding the UK from the ideal of "ever closer union".

The Tory manifesto also calls for a raft of proposals to limit the access of migrants to the British welfare system. Mr Cameron acknowledges some of these measures require "proper, full on treaty change" agreed unanimously by all 28 member states.

Can David Cameron deliver an EU referendum if he doesn't win an outright Commons majority?

Both Labour and Liberal Democrats have effectively ruled out a referendum in the next parliament, saying it would only be desirable in the unlikely event of a transfer of new powers from Westminster to Brussels.

While Labour will stick to that position, the pro-European Lib Dems might end up supporting the Tories in a hung parliament and could let Mr Cameron hold his referendum in exchange for other policy concessions.

In that event Nick Clegg, the Lib Dem leader, would insist on having a say on the negotiating strategy and would demand that 16 and 17 year olds - who tend to be pro-European - be given a vote.

What is Tory plan A on treaty change?

Mr Cameron believes the eurozone must integrate to survive, a process that will trigger treaty change. Such a fundamental overhaul would give Britain good reason - and leverage through its veto - to push through its own priorities. The trouble is that, for now, ambitious eurozone reform seems off the cards.

For the past three years, various EU institutions have floated ideas for eurozone common budgets, mutualisation of debt, stricter fiscal rules, integrated tax systems, harmonised welfare. Yet the proposals have all stalled. There has been little appetite to embark on such contentious changes amid an anti-EU backlash in many member states.

This political inertia is likely to be reflected in a report - co-ordinated by Jean-Claude Juncker, the European Commission president - to a summit of EU leaders in June. Ambitious reforms will be set out as a goal for the next ten years, not a matter for immediate action.

Does that mean eurozone-driven treaty change is ruled out?

No. A Greek exit from the eurozone is an ever growing risk and would deliver a political jolt to the EU. It could reawaken German Chancellor Angela Merkel's appetite for deeper integration, or kill off the prospect of any closer union that even hints at greater mutualisation between the creditor north and debtor south.

The mood over treaty change can also change quickly. Revisions were forced through when necessary during the eurozone crisis, for instance to create a common bailout fund. Britain's referendum may provide that impetus. Indeed Mr Cameron can make a treaty revision proposal that would be formally discussed if he has the backing of 14 other member states.

Does David Cameron need a full treaty change to deliver his objectives?

For most of his renegotiation, no. However he told the FT last month that for some proposals - for example extending the length of time a migrant must work in Britain before being eligible for benefits - his legal advice is that a treaty change is required.

But the prime minister then admitted that "legal advice in the EU is a strange beast" and that lawyers in Brussels had an uncanny knack of working their way around tricky issues.

One option is a small-scale, fast-tracked revision to the EU treaty that includes some UK specific demands. Even Francois Hollande of France has hinted at being open to more limited, surgical treaty change.

What is the fallback option?

Mr Cameron could secure a collective promise of EU leaders to include an agreed UK package of reforms whenever the treaty is next changed.

The model for this is the so-called "Edinburgh Decision" of 1992, which followed a Danish referendum rejecting the Maastricht treaty.

This has one big advantage: unlike full treaty change, it would not require referendums in other member states, which could see French or Irish voters scuppering a new UK-EU deal even after it has won approval of the British people in an in-out vote.

© The Financial Times Limited 2015. All rights reserved.
FT and Financial Times are trademarks of the Financial Times Ltd.
Not to be redistributed, copied or modified in any way.
Euro2day.gr is solely responsible for providing this translation and the Financial Times Limited does not accept any liability for the accuracy or quality of the translation