ROME, October 29 (IslamOnline.net & News Agencies) - Leaders of the European Union (EU) signed Friday, October 29, a historic constitution for the expanding bloc in a fanfare ceremony on the spot where the EU was born half a century ago, but doubts remain over whether it will ever come into force.

Putting aside for a few hours at least an institutional row over the European Union's incoming executive, the leaders trumpeted the pact as a “new beginning” for Europe.

But the assembled leaders were also urged to press ahead speedily with ratifying the constitution, which must pass referenda in at least 10 EU countries over the next two years to enter into force.

“Those decisions we cannot take for granted,” said outgoing European Commission chief Romano Prodi in a series of speeches ahead of the signing itself.

Host Silvio Berlusconi added: “The constitution that we are signing today will therefore need to be backed up by a continually renewed commitment on the part of both citizens and governments.”

The signing ceremony took place in the ornate Orazi and Curiazi hall, where the Rome Treaty which established the European Economic Community -- the EU's predecessor -- was launched by six countries March 25, 1957.

The constitution, agreed in June after two years of haggling, aims to streamline EU institutions and prevent decision-making gridlock in a bloc which grew from 15 to 25 members this year, with several more waiting in line, according to Agence France-Presse (AFP).

It notably foresees a longer-term EU presidency to replace the current six-month musical chairs system, while streamlining the executive Commission and creating a new post of EU foreign minister.

But its agreement has been accompanied by a surge of questions over whether the EU has not reached the limits of its expansion -- and question marks over whether the constitution will ever enter into force.

The constitution has still to be ratified by all 25 EU member states to come into force. The trouble is, at least one or two “no” votes are feared in the referenda to be held over the next 48 months.

Analysts say the scale of the political problem will depend on the number of no votes and, inevitably, where they occur.

A thumbs-down by Britain for example would fuel talk about sidelining some countries; a negative result in France could lead to a full-blown EU crisis or even implosion.

British Foreign Secretary Jack Straw said Friday that Britain was likely hold its referendum on the EU constitution early in 2006.

Security was ratchet-right, with some a 7,000-security force surrounding the historic centre of Rome and a squadron of F16 jet fighters enforcing a temporary no-fly zone over the city.

Even as the constitution was signed the Vatican renewed its criticism of the lack of a reference to Christianity in the pact. The Vatican's top diplomat said it enshrined anti-Christian prejudice and “cultural myopia.”

Around 100 demonstrators rallied in central Rome early Friday to protest the lack of a Christian reference.

The EU includes different ethnic and religious communities, including 20 million Muslims of the overall 200 million population.

The historic ceremonies were held on the spot where the EU was born half a century ago (AFP)

But of more immediate concern to the EU leaders is the Commission standoff.

The Rome gathering comes just two days after the European Parliament forced the embattled head of the European Commission Jose Manuel Barroso to withdraw his proposed team after protests over Italy's EU nominee for the sensitive EU justice portfolio, Rocco Buttiglione.

Berlusconi's government immediately said it will not drop the cigar-chomping Catholic, but both the Italian leader and Buttiglione are expected to come under growing pressure to “do the honorable thing.”

Italy has so far resisted pressure to withdraw Buttiglione, a conservative with outspoken views on gays and women, as its Brussels nominee. Foreign Minister Franco Frattini says Rome hopes for a speedy solution to the problem.

An earlier EU summit aimed at hammering out constitution ended in failure  with the member states battling to break a deadlock over the power-charged issue of voting rights.