By Oana Lungescu BBC correspondent in Brussels

As the European Union prepares to admit 10 new countries in an unprecedented expansion, it faces the moment of truth in relations with the longest-standing candidate, Turkey.

In an interview with the Belgian daily Le Soir this week, the EU enlargement commissioner Guenter Verheugen said a date for Turkey joining the EU remained an open question.

Admitting Turkey now would be like Mexico becoming the 51st state of the US overnight

Brussels diplomat

"Bulgaria and Romania, in 2007 perhaps," Mr Verheugen is quoted as saying. "After that, there are only question marks. Turkey? The Balkans? After that it will be finished for a while."

The European Commission upset Turkey with its latest recommendations - to be put to heads of state at a summit in Brussels next week - that no date be set for beginning membership talks with Ankara.

The commission's report welcomes Turkey's recent abolition of the death penalty, and the new language and cultural rights extended to the Kurds, but says the country still fails to meet the political criteria for entry.

Turkey sees itself as a modern, western-looking nation

Paradoxically, given the two countries' troubled history, Greece has suddenly emerged as Turkey's biggest champion within the EU.

As Ankara expressed its disappointment with the report, Greek Foreign Minister George Papndreou telephoned hisTurkish counterpart, Sukru Sina Gurel, to pledge his support for a "positive message" to be sent to Turkey at the EU's December summit in Copenhagen.

But despite Greece's desire to make a grand political gesture to Turkey, diplomats say that the most the Copenhagen summit will be able to offer Ankara is a "date for a date" at which membership talks might begin.

Apart from Greece, Britain and, more discreetly, Italy, are the only other EU members supporting this idea.

This is not like Nato expansion - it's a decision that goes far beyond foreign policy considerations

Brussels diplomat

A senior British diplomat pointed to Turkey's key strategic position which, he said, may become even more important in the next few months.

As talk of a war against Iraq intensifies, the United States has also been pressing EU leaders to give Turkey the green light, in view of its pivotal position in Nato. Officials said the commission's report showed a "lack of respect" to the Turks.

This has not gone down well in Brussels.

"This is not like Nato expansion," one diplomat said, "it's a decision that goes far beyond foreign policy considerations."

The EU is not a club of Christian peoples

European official Eneko Landaburu

"The Americans just don't understand the complexities of EU membership," said another. "Admitting Turkey now would be like Mexico becoming the 51st state of the US overnight."

The commission's director general for enlargement, Eneko Landaburu, points out that the main objection to Turkey is political, not cultural or religious.

"The EU is not a club of Christian peoples," Mr Landaburu says. "If a country shares the EU's democratic values and is European, there should be no obstacle to it joining the family."

But there are some dissenting voices even within the European Commission.

During a closed door debate on enlargement, one commissioner pointed out that only 4% of Turkey's territory actually lies in Europe.

Second thoughts

We should think of the limits of Europe, the commissioner said, comparing the Bosphorus with the Straits of Gibraltar.

Privately, EU officials admit to second thoughts about Turkey when they look at the map. Is the EU ready to have a border with countries like Iraq and Syria, one asked, especially when immigration is such a sensitive issue?

Some in Brussels hope that, in the end, Turkey will get tired of waiting and opt for stronger ties with the EU, short of full membership

And what about Turkey's 68 million people? Is the EU ready to have Turkey as itss second-biggest member after Germany, or even the biggest sometime around 2025?

In August, EU foreign ministers held a three-hour debate on enlargement at a meeting in the Danish city of Elsinore, mostly concentrating on Turkey.

Brain-storming

"It was a brain-storming session on the current situation," a diplomat said. "Everyone agreed we must keep all options open."

The optimistic scenario is that, by the end of the year, a new, reformist Turkish government will help achieve a settlement on Cyprus and solve a dispute with Greece that is currently blocking agreement on the EU's Rapid Reaction Force. That would pave the way for a clear political signal to Turkey at the EU summit in Copenhagen.

The pessimistic scenario is that the EU will invite a divided Cyprus to be one of its 10 new members, prompting Ankara to make good a threat to annex the northern part of the island. The Copenhagen summit would then mark the start of a serious crisis with Turkey.

And there is a third scenario. Some in Brussels hope that, in the end, Turkey will get tired of waiting and opt for stronger ties with the EU, short of full membership.

Turkish sources say that's just wishful thinking.