An era of change is dawning in the European Union that will transform the western half of the continent as profoundly as the eastern half was transformed in 1989. That change is coming whether or not Britain chooses to be part of it, and the result will be an EU that looks very different from the present loose union of 15 countries.
The most important change will be the creation of a single currency and of supranational political institutions to accompany it. This is likely to happen not in 1997, the earliest date envisaged in the Maastricht treaty, but in 1999, the second target date, because two years from now not enough countries will meet the treaty's conditions for forming a single currency.
The new political institutions will not mean the emergence of a European super-state governed from Brussels, or a federal United States of Europe, but they will mean considerable pooling of sovereignty by those countries involved in monetary union.
One possibility is a council of ministers, and a parliamentary authority, made up of delegates from individual countries according to the size of their populations. They would supervise economic policy in the single-currency area, but leave important powers to national or local governments.
Inevitably, many EU states will be left out of these arrangements, because they lack either the economic strength or political will to be part of them. According to a senior French government source, France believes that seven countries - Austria, Belgium, Finland, France, Germany, Luxembourg and the Netherlands - will be able to go ahead with monetary and political union.
Some European Commission officials say Ireland is a likelier candidate than Finland. But they agree that Britain and Denmark will not initially take part, having secured opt-outs under the Maastricht treaty, and that economic weakness will exclude Greece, Italy, Portugal, Spain and Sweden for the time being.
The EU may therefore have an inner core, dominated by France and Germany; a middle section, led by countries such as Italy and Spain that aspire to the inner core but must wait for economic reasons; and an outer skin, possibly consisting of Britain alone. By 2001, a fourth and fifth layer will probably take shape, made up of new EU members - the Czech Republic, Hungary, Poland and Slovakia - and EU applicants such as Cyprus, Estonia, Latvia, Lithuania, Malta and Slovenia.
European central bankers, including Hans Tietmeyer of Germany's Bundesbank and Eddie George of the Bank of England, have warned that monetary union is a complicated process that could cause immense political upheaval and economic damage if not thoroughlyprepared in advance. The bankers insist that any country joining a single currency must fulfil the strict conditions on budget deficits, national debts, interest rates and inflation stipulated in the Maastricht treaty.
Mr George, speaking in Paris last week, added that the EU should not be deluded into thinking that monetary union was feasible in the long term just because Europe's current phase of economic growth was helping certain countries to meet the Maastricht conditions. Major structural differences separated Europe's economies, and "it would be very dangerous to move to monetary union in these circumstances", he said.
What this ignores, however, is the overwhelming will for monetary and political union among politicians in France and Germany. They take the view that this momentous project has become essential now that Germany is united and the EU is poised to admit a group of relatively weak countries on Germany's eastern borders.
French politicians, in particular, say that containment of German power and of national European rivalries - two of the motives behind the foundation of the original European Economic Community in 1957 - cannot be guaranteed if EU institutions are left as loose as they are now. The only answer is monetary and political union among those countries with the necessary political commitment and economic strength.
Any British attempt to veto the project, and to turn the EU into a simple free-trade area, is doomed to failure, EU officials say. It would merely prompt the "inner core" countries to sign a new contract among themselves for monetary and political union.
However, the EU's evolution into an onion-like organisation of cores and skins will not occur without arguments. One serious flashpoint may be Belgium.
Perhaps the most ardently integrationist country in Europe, Belgium is virtually guaranteed a place in the "inner core" for political reasons. But economists say it is unlikely that Belgium will meet the Maastricht criteria for a single currency even by 1999.
The treaty allows an exception for countries deemed to be approaching the Maastricht targets, but if Belgium receives favour-able treatment in this way then countries excluded from the "inner core", notably Italy and Spain, will be furious. They could seek to block internal EU reform on a host of other fronts - as Spain did recently, when threatening to delay the accession of Austria, Finland and Norway unless it won its way on fishing rights. The Bundesbank and German parliament may object if the Maastricht rules are bent too much to suit Belgium. In the end, however, the political momentum behind monetary union is so strong that, if the ecu fails to make its debut about 2000, it may be counted as the biggest political disaster of post-war western Europe.