BRUSSELS: Where does Europe end and should the European Union go on expanding indefinitely? That is one key argument of opponents of Turkey's bid to win agreement next week to open European Union membership talks.

While Turkey's supporters see an opportunity to extend the EU's mantle of stability and prosperity to a dynamic Muslim democracy and Nato ally, adversaries fear the 25-nation grouping will over-extend itself and choke on such a giant morsel.

They see a precedent that will change the EU from a close-knit community into an unwieldy "regional United Nations" sprawling into central Asia and North Africa. If the EU says "yes" to Turkey, how could it say "no" to Ukraine, Belarus, Georgia, Armenia and eventually Russia and Morocco, the critics ask.

"Turkey is an Asian country with a small bridgehead in Europe, with the elite looking to Europe ... but the vast majority rooted in Asia," former EU farm chief Franz Fischler said in a letter to his colleagues this year.

The EU would be unable to sustain its two main spending policies, agricultural support and regional development aid, even if Turkish membership were phased in over a decade, and it would open "a geo strategic Pandora's box", the Austrian warned.

The man who drafted the EU constitution, former French President Valery Giscard d'Estaing, was even more blunt. Turkey was not geographically or culturally European, and its accession would be "the end of the European Union", Giscard told the French daily Le Monde in November 2002.

Furthermore, those pushing Turkish membership most strongly were the enemies of European integration, Giscard asserted - a reference to Britain and the United States. Rising French political star Nicolas Sarkozy, leader of the ruling UMP party, last month rejected Turkish entry and said the indefinite expansion of the EU was "an American vision".

DIFFERENT EUROPE: Turkish accession in a decade or so would certainly create a very different EU, shifting the balance of power still further away from its original Franco-German axis - hence French alarm.

By the time it joined, Turkey would be the most populous nation in the EU, overtaking Germany's 80 million. That would give it the most voting power under the largely population-based voting system established by the constitution, and the biggest block of seats in the European Parliament.

The EU would no longer be able to afford to subsidise farmers and poor regions on the current scale. To some critics, notably in France, that would reduce it to a vast free trade area with little or no redistribution of wealth.

Countries such as Britain and Sweden make little secret of their delight at such a prospect. Turkey's supporters argue that the EU is already evolving with the admission of 10 mainly poor east European countries this year, and its farm and regional policies will have to change anyway due to world trade talks and budget constraints.

They also argue that the accession of a country with a surplus of eager young workers could boost Europe's dwindling, ageing workforce and help defuse a looming pensions crisis.

But European Commission economists say an influx of Turkish labour, likely to be long delayed by transition arrangements, would do little to ease the pensions shortfall.

Then there is the cultural argument - a euphemism for religion in some eyes, or for a history of enmity in others. Dutch former EU commissioner Frits Bolkestein articulated an often unspoken fear of Europe being overrun by Islam.

In a speech in September, he suggested that Ankara's accesion would reverse the 1683 defeat of the Turks at the gates of Vienna, which marked the limit of the westward expansion of the Ottoman empire in Europe.

Jean-Louis Bour langes, a centre-right French member of the European Parliament and leading European federalist, said the EU's extension into eastern Europe was a natural reunification with "the kidnapped east". But admitting Turkey would be quite different.

"(Turkish Prime Minister Tayyip) Erdogan says the EU should be a crossroads of civilizations. We consider it is the home of a civilization. European identity shouldn't be a department store," Bourlanges said. -Reuters