BRUSSELS: The atmosphere in Brussels has been surreal for weeks- business goes on as usual, officials are barred from using the word "Brexit" and life proceeds as if Britain's EU referendum does not exist.

But this phoney calm belies the fact that, whether Britons vote to leave or remain on Thursday, the European Union will have to make some of the biggest changes in its history in order to survive.

If Britain becomes the first member state to leave the EU, it could trigger the beginning of the end for a beleaguered union mired in a migration crisis, economic woes and a growing threat of terrorism.

Even if it stays, the status quo will not be an option, with the questions raised by Britain's referendum reverberating around a continent that is losing faith in the post-war European dream.

"Whatever its result is going to be, we must take a long hard look at the future of the union. We would be foolish if we ignored such a warning signal as the UK referendum," EU President Donald Tusk warned this week.

The first problem the EU's fractious leaders will face after the vote is finding any agreement on the way forward, when they have found it so hard to make deals on other crises.

"There is all this sentiment that Europe must change in order to survive," Chris Bickerton, a lecturer at Britain's Cambridge University and author of The European Union: A Citizen's Guide, said.

"But if you go through the practical details you quickly come up against these difficulties."

A British exit will plunge the EU into years of bitter divorce negotiations between Brussels and London, although in some quarters at least there are hopes it will at least let the rest of the bloc get on with its work.

"It's very possible that the EU institutions will have this 'back to work, back to normal' reflex'," Vivien Pertusot, Brussels-based analyst with the French Institute of International Relations (IFRI), said.

That may be easier said than done.

France and Germany have discussed a joint plan for Europe after the British vote. French President Hollande said Wednesday he would launch "Europe-wide initiatives" whatever the result in Britain.

But Berlin and Paris are already at loggerheads over the integration of the eurozone, meaning any plan will "strictly adhere to security and defence", a senior eurozone official said on condition of anonymity.

- The Economic Times