Soon after the British embassy in Dublin's Merrion Square was burned by demonstrators enraged at the Bloody Sunday massacre, the Irish electorate made two fundamental changes to its expression of national identity. On a wet day in 1972, constitutional referendums paved the way for joining the EEC, while altering the special status of the Catholic Church in Ireland.

The church's official constitutional spree had lasted only 35 years, but what a time it had been. Years when owning the image of being a daily communicant won you social status far beyond your economic power; when, however threadbare the moral fibre within your mohair suit, a quick trip to Confession guaranteed you the spiritual grooming of a newly-baptised baby.

This week's Prime Time/MRBI survey confirmed what the dogs in the streets had known for quite some time: the hegemony of the Catholic Church is gone for good, and no one seems the worse for it. Within the past four years weekly Mass attendance, a spiritual mustdo for Catholics, has dropped by 17 per cent, and Confession is now a practice confined mainly to older people.

A la carte Catholicism, that contemptuous phrase so often used to suggest spiritual deviancy, is the order of the day for most Catholics: the majority disagree with official church teaching on contraception, divorce, priestly celibacy and women priests. Some 60 per cent still attend weekly Mass, but if Ireland follows European trends, not to mention that of other Christian churches in Ireland where church attendance is not mandatory, weekly congregations will drop even more during the next decade.

Ireland is becoming a nation of protestants. In an age when virtually every human experience is mediated by some class of professional, the religious experience alone is increasingly exercised one-to-one.

The surprise is not that it is happening, but that the Catholic Church itself predicted such a phenomenon long ago. Even the ultra-conservative Bishop Jeremiah Newman prophesied the move from a widespread public spirituality to a more private devotional form. But so assumed was the church's place within the culture at large that few foresaw the speed with which mass appeal would become mass exit.

Irish identity itself seemed umbilically tied to Catholicism: a 1973 survey showed weekly congregations of 91 per cent, and throughout the 1970s, the charismatic movement breathed tongues of fire on prayer groups all over the country. Some loosening of the bonds between church and State could therefore be allowed, it may have seemed, on the assumption that Catholic consciences would continue to express their citizenship within the grammar of Canon Law.

Thus, as control over the State waned, controls over individuals increased by the day. Ignoring messages expressed by such various movements as liberation theology and feminism, the official church sought to recolonise its membership by articulating legalistic behaviour codes which did little to resolve the messy ethical dilemmas now becoming part and parcel of each individual life. Fertility rates halved within a generation: few ascribed the lower birth rate to natural causes.

In a sense, Pope John Paul's 1979 visit was the last-ditch attempt to retain Ireland as a Catholic society with Catholic values, a revision of Padraig Pearse's ambition that Ireland be "the saviour of idealism in Europe". But the theological tension between the Pope's interpretation of Catholicism in the world and that of nuns and priests in front-line ministries, such as Africa and South America, soon came to a head.

Writing months before the papal visit in 1979, the Rev Prof Liam Ryan had argued that the church's role was increasingly seen as "the conscience of society", as "an instrument of social renewal".

Yet, by the time of the Pope's visit to South America in 1980, it was clear that the social action demanded by liberation theologians, who believed that nothing short of world transformation could honour the message of Jesus Christ, had been beaten into submission by the old-style, Euro-centred strategies of the Vatican.

It worked for a while. In the claustrophobic 1980s, church opposition to divorce and abortion won it some major victories, but the electorate's eventual response to human crises like marriage breakdown and the X case gave the lie to any prospect of individual Catholics blindly translating their religious convictions to a civic context.

Irish Catholics, like Irish Protestants, were increasingly able to distinguish the implications of making a pluralist society from the individual choices which followed membership of an institutional church.

But with the safety net gone, what replaces those old notions of public spirituality? Already, Catholic commentators are associating the decline in Mass attendance with massively increased prosperity, as if to argue that Catholicism is the opium of the poor, or to imply that people can be bought off by economic factors.

But so easy an equivalence masks the historical association of prosperity with increased devotional practice which to date marks Irish history. Only with the rise of the Catholic middle class in the late 19th century did Mass attendance leap from its mid-century rate of approximately 35 per cent to its turn-of-the-century total of some 90 per cent.

And as the Prime Time report by Tamsin Fontes and Michael Ronayne discovered, the worst attendance rates seem to be in the most economically deprived communities.

To ascribe changes demonstrated in the survey to a lethal combination of prosperity spiced by clerical scandals, like the Brendan Smyth and Bishop Eamonn Casey circuses, is to ignore the survey's real civic implications. So far, a separation of church and State has blurred many lines, not least of which is the question of who, how and where responsibility for identifying and acting on social injustice now lies.

Although the belief that religious institutions are best equipped to start the process still finds considerable support, so, too, does its counter that secular protections are enough to guarantee social justice.

Meanwhile, there's a black hole gaping while the arguments go on, bringing casualties already, communities dispossessed because of unemployment and drug abuse. We also see a laissez-faire attitude to the treatment of refugees best demonstrated by the failure to implement new legislation, based, it would seem, on administrative convenience; off-shore banking of much on-shore generated new wealth.

Perhaps the Catholic Church will become a kind of spiritual undertaker to Irish society, there for rites of passage like birth, marriage and death. That sheer neighbourliness of going to Mass each Sunday now finds other expressions, sharing soap opera, chatting on the Internet.

The Prime Time survey confirms yet again what everybody now realises: when Irish society changes, it does so faster than you can say "intercommunion".