The draft constitution already mentions “religion”; just not explicitly the Christian (or any other specific) religion.
From the preamble
*“Drawing inspiration from the cultural, religious and humanist inheritance of Europe, the values of which, still present in its heritage, have embedded within the life of society the central role of the human person and his or her inviolable and inalienable rights, and respect for law, . . . *
The preamble doesn’t have any operative effect on its own, but it sets the context within which the operative provisions of the constitution will be interpreted and applied.
A reference to “the religious inheritance of Europe” is plainly a reference predominantly to Christianity, or at least it can easily be so interpreted. Some of the proposed amendments have sought to make this explicit. Others have been an attempt to <i>broaden</i> the reference, by explicitly including other religious traditions. Still other proposed amendments have sought to balance the reference to “religious heritage” with one to “lay (or secular) heritage” or to to Greek and Roman civilisations and/or the Enlightenment, or to refer to Greece, Rome, the Enlightenment and so forth but not to religion, or to drop the whole philosophical heritage bit altogether.
Dropping all reference to God or religion isn’t necessarily a neutral position; to mention some ethical values (or sources of ethical values) while overlooking others is not “neutral” with respect either to those mentioned or those overlooked. To mention none at all would be “neutral” as between the various value systems, but the courts and other institutions are going to bring <i>some</I> value system to bear in applying and interpreting the constitution; shouldn’t the drafters of the constution ignore that reality, and let the courts, etc, decide for themselves where to find their values?
The present draft is obviously a compromise; a non-specific reference to religion in a list of sources of ethical values. Like a lot of compromises, it probably dissatisfies more people than it satisfies, but there is no common ground among the dissatisified, and they criticise it for different reasons.
Brainglutton asks what the position of the UK government was on this issue. It doesn’t have a position; none of the member states governments do. The Constitition was drafted in the European Convention, a body which included members from all the member states (and candidate states). But the members of the Convention did not represent their national governments or national parliaments, and they did not vote in national blocs. They adopted individual positions, and were more likely to align with politically like-minded colleagues from other states than with colleagues from their own states.
The national governments will have to decide whether to ratify the Constitution or not, but they ratify it as a whole; they won’t have to adopt specific positions on this or that element of it.