The European Commission has warned that a future EU constitution can not give legal force to a statement of religious values.

Acknowledging that a row over calls for a religious reference to Christianity in a new blueprint for the European Union was "tricky", a Brussels spokesman said that the commission "had not taken a formal position".

But he would not "rule out" a statement of belief - including a spiritual component - in a non-binding preamble to a future European constitution.

Any reference to religion would not be in an EU treaty of fundamental values, he said. Such a document would deal with practical issues with "legal consequences".

Commission president Romano Prodi has previously indicated that European unity has a Christian aspect in terms of shared cultural heritage.

But speaking on Thursday, his spokesman told journalists that Brussels was seeking a "good wording that will take on board the whole of European civilisation".

"[The approach] is all on having a drafting that states out all values that bring Europeans together without going against any beliefs of the European population," he said.

As convention delegates gather in Brussels, UK MPs involved in the negotiations warned earlier this week that the Christian religious tradition has "no place" in a new constitution for Europe.Gisela Stuart and David Heathcoat-Amory, parliament's two delegates to the Convention on the Future of Europe, are opposed to a "religious reference" in any future statement of the political principles underpinning the European Union.

Behind the scenes moves by some of Europe's powerful centre-right politicians and the Catholic church to get a commitment to religious belief in a declaration of EU "values" have opened up deep divisions.But Stuart, a member of the convention's praesidium, argues that such a stance is out of step with today's secular and ethnically diverse European Union.

"Assertion of Christian religious belief clearly has no place in the constitution," she told ePolitix.com.

"EU values have grown out of Christian traditions but today we have huge Muslim communities and I think that would be the wrong direction."

Heathcoat-Amory has a fundamental objection to the whole idea of an EU constitution which "gives rise to these kinds of controversies".Calls for a "God" reference in any statement of European principles, he says, are meaningless outside a Christian context, which he claims would alienate Turkey.

"I am not in favour," he told ePolitix.com. "If it means anything it is the Christian God and what are the Turks to make of that?"

"It is one thing to have a constitution for a people like the Americans but raises issues in a diverse Europe."