Speaking at the launch of a Handbook on referendums, Alain Lamassoure, a conservative MEP and strong advocate of a European-wide referendum on the Constitution says there will be a "major crisis" if several countries turn down the new Constitution.

However, he also concedes: "We're not going to build a political union against the citizens' wishes".

Jürgen Meyer, German MP and Constitution expert said that it is "only through a referendum that you can get into peoples' heads and hearts".

But, the Constitution as it stands provides no definitive answer to what should happen if some countries, either via their national parliaments or via referendum, reject the Constitution.

Article *IV-8 simply states:

1. The Treaty establishing the Constitution shall be ratified by the High Contracting Parties in accordance with their respective constitutional requirements. The instruments of ratification shall be deposited with the Government of the Italian Republic.

2. The Treaty establishing the Constitution shall enter into force on ...., provided that all the instruments of ratification have been deposited, or, failing that, on the first day of the month following the deposit of the instrument of ratification by the last signatory State to take this step"

A big No and a little No

In any case, should one of the 25 member states say no - and this is very likely to happen as the recent examples in Sweden (on the Euro) and Ireland (on the Nice Treaty) already show - it will cause huge political turmoil.

Mr Lamassoure expresses what is on several diplomats' minds - especially from the larger more pro-integration member states - about what will happen if just one small member state turns the treaty down.

"A no from Malta is not going to have the same impact as a no from France", he says

Federalists and sceptics: uneasy bedfellows

For the moment, however, the aim is to get the European debate on the Constitution. And there both EU integrationists and euro-sceptics share the same uneasy platform.

Eurosceptics want the Constitution to be put to a referendum as they are aware of the high risk in it getting rejected; they also abhor the fact that Constitution, which will fundamentally alter the nature of the Union, has seen so little debate in the member states.

Federalists also worry about democratic legitimacy without a referendum. They believe, however, that if there is a European-wide referendum with the accompanying EU debate, then the risk of people voting No for internal political reasons will be reduced.

At the moment, Denmark, Ireland, France, Luxembourg, the Netherlands, Spain, Portugal and the Czech Republic are set to have referendums.

It is also looking very likely in Italy, Belgium and Slovenia.

*Please note that an earlier version of this article made reference to Art. IV - 7.4 which refers to amendments to the Constitution after it has been ratified. Art. IV - 8 refers to the initial ratification of the Treaty establishing a Constitution for Europe. The author would like to apologise for this error